研究者詳細 - 加茂　憲一

論文 - 加茂　憲一

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Selection Method for Height-Diameter Curves and Its Application to the Data of Sugi (<i>Cryptomeria japonica</i>) in Japan

Ken-ichi Kamo, Tetsuji Tonda, Masayoshi Takahashi, Naoto Matsumura

FORMATH ( FORMATH Research Group ) 22 n/a - n/a 2023年12月

DOI

Strength estimation for moving iodine-125 source for brachytherapy; application to source link loader”

K.Tanaka, T.Kajimoto, O.Asanuma, M.Hori, K.Kamo, T.Suzuki, I.Sumida, Y.Takahashi, G.Bengua, K.Sakata, S.Endo

Bulletin of Kyoto Pharmaceutical University 4 167 - 174 2023年12月 [査読有り]

DOI

Cost-effectiveness of preventive aspirin use and intensive downstaging polypectomy in patients with familial adenomatous polyposis: A microsimulation modeling study.

Eiko Saito, Michihiro Mutoh, Hideki Ishikawa, Kenichi Kamo, Keisuke Fukui, Megumi Hori, Yuri Ito, Yichi Chen, Byron Sigel, Masau Sekiguchi, Osamu Hemmi, Kota Katanoda

Cancer medicine 2023年08月 [査読有り] [国際誌]

OBJECTIVE: Although there is increasing evidence to suggest the cost-effectiveness of aspirin use to prevent colorectal cancer (CRC) in the general population, no study has assessed cost-effectiveness in patients with familial adenomatous polyposis (FAP), who are at high risk of developing CRC. We examined the cost-effectiveness of preventive use of low-dose aspirin in FAP patients who had undergone polypectomy in comparison with current treatment practice. DESIGN: We developed a microsimulation model that simulates a hypothetical cohort of the Japanese population with FAP for 40 years. Three scenarios were created based on three intervention strategies for comparison with no intervention, namely intensive downstaging polypectomy (IDP) of colorectal polyps at least 5.0 mm in diameter, IDP combined with low-dose aspirin, and total proctocolectomy with ileal pouch-anal anastomosis (IPAA). Cost-effective strategies were identified using a willingness-to-pay threshold of USD 50,000 per QALY gained. RESULTS: Compared with no intervention, all strategies resulted in extended QALYs (21.01-21.43 QALYs per individual) and showed considerably reduced colorectal cancer mortality (23.35-53.62 CRC deaths per 1000 individuals). Based on the willingness-to-pay threshold, IDP with low-dose aspirin was more cost-effective than the other strategies, with an incremental cost-effectiveness ratio of $57 compared with no preventive intervention. These findings were confirmed in both one-way sensitivity analyses and probabilistic sensitivity analyses. CONCLUSION: This study suggests that the strategy of low-dose aspirin with IDP may be cost-effective compared with IDP-only or IPAA under the national fee schedule of Japan.

DOI PubMed

Statistical Inference for Diameter-Height Curves using Varying Coefficient Model

Tetsuji Tonda, Ken-ichi Kamo, Masayoshi Takahashi

FORMATH ( FORMATH Research Group ) 22 n/a - n/a 2023年

DOI

How much can screening reduce colorectal cancer mortality in Japan? Scenario-based estimation by microsimulation.

Ken-Ichi Kamo, Keisuke Fukui, Yuri Ito, Tomio Nakayama, Kota Katanoda

Japanese journal of clinical oncology 52 ( 3 ) 221 - 226 2021年12月 [査読有り] [国際誌]

担当区分：筆頭著者 , 責任著者

BACKGROUND: Screening is one of the effective interventions for the reduction of colorectal cancer mortality. Though the Japanese government recommends faecal occult blood test and colonoscopy as a follow-up examination following a diagnosis, both participation rates have not been so high and the national mortality rate has not shown a clear decreasing trend. METHODS: Microsimulation models simulate the life histories of a large population of individuals under various scenarios. In this study, we applied a microsimulation model to estimate the reduction of colorectal cancer mortality based on screening scenarios. RESULTS: The effect of reducing the age-standardized mortality rate for colorectal cancer was estimated at 9.4% for men and 6.0% for women under the scenario which calls for 50% participation in faecal occult blood test and 90% participation of follow-up examination. This scenario corresponds to the goal setting for screening in the third-term of the Basic Plan to Promote Cancer Control Programs in Japan. CONCLUSIONS: Our microsimulation model was found to be useful in estimating the mortality reduction effect of cancer control policy. Such modelling techniques can be utilized to develop effective and optimal cancer control programs.

DOI PubMed

Ridge Estimate Application to Growth Function

Ken-ichi Kamo, Hirokazu Yanagihara

FORMATH ( FORMATH Research Group ) 20 n/a - n/a 2021年09月 [査読有り]

担当区分：筆頭著者 , 責任著者

DOI

Assessing the Immediate Impact of Surrounding Land Uses on the Extents of Freshwater Body over Time in Madagascar - A Demonstrative Case Study of Itasy Lake -

Masashi Konoshima, Tetsuji Tonda, Ken-ichi Kamo, Bam H.N. Razafindrabe

FORMATH ( FORMATH Research Group ) 20 n/a - n/a 2021年09月 [査読有り]

DOI

Gamma Regression Model with Nuisance Baseline for Tree Growth Data

Tetsuji Tonda, Ken-ichi Kamo, Masayoshi Takahashi

FORMATH ( FORMATH Research Group ) 20 n/a - n/a 2021年09月 [査読有り]

DOI

がん対策立案・評価における意思決定に寄与するマイクロシミュレーションの構築：大腸がんを事例に

加茂憲一, 福井敬祐, 坂本亘, 伊藤ゆり

計量生物学 ( The Biometric Society of Japan ) 41 ( 2 ) 93 - 115 2021年05月 [査読有り]

担当区分：筆頭著者 , 責任著者

DOI J-GLOBAL

A modified GAP model for East-Asian populations with idiopathic pulmonary fibrosis

Hirotaka Nishikiori, Hirofumi Chiba, Sang Hoon Lee, Shun Kondoh, Ken-ichi Kamo, Koshi Nakamura, Kimiyuki Ikeda, Koji Kuronuma, Man Pyo Chung, Yasuhiro Kondoh, Sakae Homma, Naohiko Inase, Moo Suk Park, Hiroki Takahashi

Respiratory Investigation ( Elsevier BV ) 58 ( 5 ) 395 - 402 2020年09月 [査読有り] [国際誌]

BACKGROUND: The easy-to-calculate gender, age, and lung physiology (GAP) model shows good predictive and discriminative performance in the prognosis of idiopathic pulmonary fibrosis (IPF). However, the GAP model was not effective in predicting the prognosis accurately in previous Japanese and Korean IPF cohort studies. Therefore, we developed a modified GAP model for the East-Asian populations by weighing the GAP variables. The validity of the modified GAP model was subsequently evaluated in East-Asian IPF patients. METHODS: The derivation cohort comprised 326 patients with IPF. Weights of the variables were adjusted on the basis of coefficients derived from Cox regression models. The total points were distributed to the three stages of the disease so that the number of patients included in each stage was appropriate. The validity of the modified model was analyzed in another Japanese cohort of 117 patients with IPF and a nationwide cohort of Korean patients with IPF. RESULTS: Predicted survival rates differed significantly in the derivation cohort using the modified GAP model for each stage of IPF (log-rank test: stage I vs. stage II, p < 0.001; stage II vs. stage III, p < 0.001). Model performance improved according to Harrell's C-index (at three years: 0.696 in the original GAP model to 0.738 in the modified model). The performance of the modified model was validated in the Japanese validation and Korean national cohorts. CONCLUSIONS: Our modification of the original GAP model showed improved performance in East-Asian IPF patient populations.

DOI PubMed

Lateral Position With Gantry Tilt Further Improves Computed Tomography Image Quality Reconstructed Using Single-Energy Metal Artifact Reduction Algorithm in the Oral Cavity

Maki Onodera, Kazunori Aratani, Takaharu Shonai, Keishi Ogura, Ken-ichi Kamo, Kazuhiro Ogi, Atsushi Kondo, Masamitsu Hatakenaka

Journal of Computer Assisted Tomography ( Ovid Technologies (Wolters Kluwer Health) ) 44 ( 4 ) 553 - 558 2020年07月 [査読有り]

DOI

Statistical inference for estimating the incidence of cancer at the prefectural level in Japan

Tanabe Ryunosuke, Kamo Ken-ichi, Fukui Keisuke, Imori Shinpei

JAPANESE JOURNAL OF CLINICAL ONCOLOGY 49 ( 5 ) 481 - 485 2019年05月 [査読有り]

担当区分：責任著者

DOI

A New Approach to Classify Growth Patterns Based on Growth Function Selection and K-means Method

Ken-ichi Kamo

FORMATH ( FORMATH Research Group ) 18 ( 0 ) n/a - n/a 2019年04月 [査読有り]

担当区分：筆頭著者 , 責任著者

DOI

Simulation Models in Gastric Cancer Screening: A Systematic Review

Ayako Matsuda, Kumiko Saika, Rina Tanaka, Yuri Ito, Keisuke Fukui, Ken-ichi Kamo

Asian Pacific journal of cancer prevention : APJCP 19 ( 12 ) 3321 - 3334 2018年12月 [査読有り] [国際誌]

担当区分：最終著者

Background: Together with such high-quality approaches as randomized controlled trials and large-scale cohort studies, simulation models are often employed to evaluate the effect of cancer screening methods and decide on their appropriateness. This study aimed to evaluate all effects of gastric cancer screening that have been assessed using simulation models, including cost-effectiveness, mortality reduction, and early-stage detection. Methods: We performed a systematic review using PubMed and Web of Science. We evaluated the effect of screening related to cost, such as incremental cost-effectiveness and incremental cost-effectiveness ratios; we also separately assessed effects other than cost, such as quality-adjusted life-years, number of deaths prevented, life-years saved, relative risk of mortality from gastric cancer, life expectancy, and incidence reduction. The methods targeted for evaluation were Helicobacter pylori testing or endoscopy. Results: We identified 19 studies dealing with simulation models in gastric cancer screenings: 14 examined H. pylori screening and 7 focused on endoscopy. Among those studies, two assessed both H. pylori and endoscopy screening. Most of the studies adopted a Markov model, and all the studies evaluated cost-effectiveness. Of the 14 H. pylori screening studies, 13 demonstrated cost-effectiveness and 11 also showed good results other than cost-effectiveness, such as extension of life-years and increase in early-stage detection. In three of the five endoscopy studies, the target population was patients; all five studies obtained good results for cost-effectiveness and four observed good results other than for cost-effectiveness. Conclusions: In this study, we showed that the H. pylori screening test was cost-effective in terms of simulation model investigations. However, the H. pylori screening test should not ordinarily be recommended since there is insufficient evidence that it reduces gastric cancer mortality. In Japan, simulation modeling should be employed to plan for cancer control, and the appropriate use of simulation models should be examined for future use.

PubMed

Long-term prognosis of patients with HHV-6 reactivation following allogeneic HSCT

K.Iesato, T.Hori, Y.Yoto, M.Yamamoto, N.Inazawa, K.Kamo, H.Ikeda, S.Iyama, N.Hatakeyama, A.Iguchi, J.Sugita, R.Kobayashi, N.Suzuki, H.Tsutsumi

Pediatrics International 60 547 - 552 2018年 [査読有り]

An in vitro verification of strength estimation for moving an 125iodine source during implantation in brachytherapy

K.Tanaka, T.Kajimoto, T.Hayashi, O.Asanuma, M.Hori, K.Kamo, I.Sumida, Y.Takahashi, K.Tateoka, G.Bengua, K.Sakata, S.Endo

Journal of Radiation Research 59 ( 4 ) 484 - 489 2018年 [査読有り]

A STUDY ON THE BIAS-CORRECTION EFFECT OF THE AIC FOR SELECTING VARIABLES IN NORMAL MULTIVARIATE LINEAR REGRESSION MODELS UNDER MODEL MISSPECIFICATION

Hirokazu Yanagihara, Ken-ichi Kamo, Shinpei Imori, Mariko Yamamura

REVSTAT-STATISTICAL JOURNAL ( INST NACIONAL ESTATISTICA-INE ) 15 ( 3 ) 299 - 332 2017年07月 [査読有り]

By numerically comparing a variable-selection method using the crude AIC with those using the bias-corrected AICs, we find out knowledge about what kind of bias correction gives a positive effect to variable selection under model misspecification. Actually, since all the variable-selection methods considered in this paper asymptotically choose the same model as the best model, we conduct numerical examinations using small and moderate sample sizes. Our results show that bias correction under assumption that the mean structure is misspecified gives a better effect to a variable-selection method than that under the assumption that the distribution of the model is misspecified.

Growth analysis using nuisance baseline

K.Kamo, T.Tonda, K.Satoh

FORMATH 16 1 - 10 2017年 [査読有り]

担当区分：筆頭著者 , 責任著者

The signal intensity ratio of the optic nerve to ipsilateral frontal white matter is of value in the diagnosis of acute optic neuritis

Maki Onodera, Naoya Yama, Masato Hashimoto, Takaharu Shonai, Kazunori Aratani, Hiroyuki Takashima, Ken-ichi Kamo, Hiroshi Nagahama, Hiroshi Ohguro, Masamitsu Hatakenaka

EUROPEAN RADIOLOGY ( SPRINGER ) 26 ( 8 ) 2640 - 2645 2016年08月 [査読有り]

To evaluate the usefulness of the signal intensity ratio (SIR) of the optic nerve to the white matter (WM) on short tau inversion recovery (STIR) images to diagnose acute optic neuritis (AON). The 405 consecutive patients with suspected orbital diseases underwent orbital magnetic resonance imaging (MRI) using a 3-T scanner between June 2008 and August 2011. Among them, 108 optic nerves (33 AON and 75 control) were retrospectively analysed. The averaged SIR (SIRave) and maximum SIR (SIRmax) were defined as the averaged signal intensity (SI) of the optic nerve divided by that of WM, and the maximum SI of the optic nerve divided by averaged SI of WM, respectively. These values were compared between AON and control using the Mann-Whitney U test. A P < 0.05 was considered statistically significant. SIRave and SIRmax were significantly (P < 0.001) higher in the AON compared to the control. At a cut-off SIRave value of 1.119, the sensitivity, specificity and accuracy were 0.939, 0.840, and 0.870; and at a cut-off SIRmax value of 1.281, these were 1.000, 0.720 and 0.806, respectively. The SIR of the optic nerve to WM on STIR images is of value in diagnosing AON. aEuro cent We propose a method of diagnosing acute optic neuritis using 3-T MRI. aEuro cent Our method is simple and objective and requires no novel imaging techniques. aEuro cent Our method shows high diagnostic accuracy.

DOI

Quantification of the increase in thyroid cancer prevalence in Fukushima after the nuclear disaster in 2011-a potential overdiagnosis?

Kota Katanoda, Ken-Ichi Kamo, Shoichiro Tsugane

JAPANESE JOURNAL OF CLINICAL ONCOLOGY ( OXFORD UNIV PRESS ) 46 ( 3 ) 284 - 286 2016年03月 [査読有り]

A thyroid ultrasound examination programme has been conducted in Fukushima Prefecture, Japan, after the nuclear disaster in 2011. Although remarkably high prevalence of thyroid cancer was observed, no relevant quantitative evaluation was conducted. We calculated the observed/expected (O/E) ratio of thyroid cancer prevalence for the residents aged a parts per thousand currency sign20 years. Observed prevalence was the number of thyroid cancer cases detected by the programme through the end of April 2015. Expected prevalence was calculated as cumulative incidence by a life-table method using the national estimates of thyroid cancer incidence rate in 2001-10 (prior to the disaster) and the population of Fukushima Prefecture. The underlying assumption was that there was neither nuclear accident nor screening intervention. The observed and estimated prevalence of thyroid cancer among residents aged a parts per thousand currency sign20 years was 160.1 and 5.2, respectively, giving an O/E ratio of 30.8 [95% confidence interval (CI): 26.2, 35.9]. When the recent increasing trend in thyroid cancer was considered, the overall O/E ratio was 22.2 (95% CI: 18.9, 25.9). The cumulative number of thyroid cancer deaths in Fukushima Prefecture, estimated with the same method (annual average in 2009-13), was 0.6 under age 40. Combined with the existing knowledge about radiation effect on thyroid cancer, our descriptive analysis suggests the possibility of overdiagnosis. Evaluation including individual-level analysis is required to further clarify the contribution of underlying factors.

DOI

Statisitcal analysis of tree–forest damage by snow and wind: logistic regression model for tree damage and Cox regression for tree survival

K.Kamo, M.Konoshima, A.Yoshimoto

FORMATH ( FORMATH研究会 ) 15 44 - 55 2016年 [査読有り]

担当区分：筆頭著者 , 責任著者

Forest stands and individual trees are often devastated by natural disasters such as typhoons and heavy snowfall in Japan, resulting in significant economic losses to the forestry sector. Our objective is to identify key risk factors that affect the degree of damage. We apply two types of statistical approach: one is, a logistic regression model to snow damage data to investigate if there is any geographical element affecting the degree of damage at the stand level, and the other is, a survival analysis on tree failure data for factors affecting the degree of damage at the individual tree level. A logistic regression analysis revealed that the risk probability of snow damage is higher on older and thin stands. The analysis also indicates taking advantage of certain geographic conditions to reduce wind burden could decrease the degree of damage. A Cox regression analysis showed that tree age, diameter at breast height, and species were key factors that influenced the degree of tree failure. Specifying risk factors throughout statistical modeling helps to provide a comprehensive, systematic, and objective method to assess risk in forest management.

DOI CiNii

“A comparison of the dose distributions between the brachytherapy 125I source models, STM1251 and Oncoseed 6711, in a geometry lacking radiation equilibrium scatter conditions.”,

K. Tanaka, K. Kamo, K. Tateoka, O. Asanuma, K. Sato, H. Takeda, K. Sakata, J. Takada

Journal of Radiation Research, 55 (2015) 000-000. 55 1 - 6 2015年04月 [査読有り]

DOI

A comparison of the dose distributions between the brachytherapy I-125 source models, STM1251 and Oncoseed 6711, in a geometry lacking radiation equilibrium scatter conditions

Kenichi Tanaka, Ken-ichi Kamo, Kunihiko Tateoka, Osamu Asanuma, Kaori Sato, Hiromitsu Takeda, Koh-ichi Sakata, Jun Takada

JOURNAL OF RADIATION RESEARCH ( OXFORD UNIV PRESS ) 56 ( 2 ) 366 - 371 2015年03月 [査読有り]

The purpose of this study was to estimate the uncertainty in the dose distribution for the I-125 source STM1251, as measured with a radiophotoluminescent glass rod dosimeter and calculated using the Monte Carlo code EGS5 in geometry that included the source structure reported by Kirov et al. This was performed at a range of positions in and on a water phantom 18 cm in diameter and 16 cm in length. Some dosimetry positions were so close to the surface that the backscatter margin was insufficient for photons. Consequently, the combined standard uncertainty (CSU) at the coverage factor k of 1 was 11.0-11.2% for the measurement and 1.8-3.6% for the calculation. The calculation successfully reproduced the measured dose distribution within 13%, with CSU at k = 1.6 (P > 0.3). Dose distributions were then compared with those for the I-125 source Oncoseed 6711. Our results supported the American Association of Physicists in Medicine Task Group No. 43 Updated Protocol (TG43U1) formalism, in which STM1251 dose distributions were more penetrating than those of Oncoseed 6711. This trend was also observed in the region near the phantom surface lacking the equilibrium radiation scatter conditions. In this region, the difference between the TG43U1 formalism and the measurement and calculation performed in the present study was not significant (P > 0.3) for either of the source models. Selection of the source model based on the treatment plans according to the TG43U1 formalism will be practical.

DOI

Detecting a Local Cohort Effect for Cancer Mortality Data Using a Varying Coefficient Model

Tetsuji Tonda, Kenichi Satoh, Ken-ichi Kamo

JOURNAL OF EPIDEMIOLOGY ( JAPAN EPIDEMIOLOGICAL ASSOC ) 25 ( 10 ) 639 - 646 2015年 [査読有り]

Background: Cancer mortality is increasing with the aging of the population in Japan. Cancer information obtained through feasible methods is therefore becoming the basis for planning effective cancer control programs. There are three time-related factors affecting cancer mortality, of which the cohort effect is one. Past descriptive epidemiologic studies suggest that the cohort effect is not negligible in cancer mortality. Methods: In this paper, we develop a statistical method for automatically detecting a cohort effect and assessing its statistical significance for cancer mortality data using a varying coefficient model. Results: The proposed method was applied to liver and lung cancer mortality data on Japanese men for illustration. Our method detected significant positive or negative cohort effects. The relative risk was 1.54 for liver cancer mortality in the cohort born around 1934 and 0.83 for lung cancer in the cohort born around 1939. Conclusions: Cohort effects detected using the proposed method agree well with previous descriptive epidemiologic findings. In addition, the proposed method is expected to be sensitive enough to detect smaller, previously undetected birth cohort effects.

DOI

Strength estimation of a moving (125)Iodine source during implantation in brachytherapy: application to linked sources

Kenichi Tanaka, Satoru Endo, Kunihiko Tateoka, Osamu Asanuma, Masakazu Hori, Masaru Takagi, Gerard Bengua, Ken-ichi Kamo, Kaori Sato, Hiromitsu Takeda, Masato Hareyama, Koh-ichi Sakata, Jun Takada

JOURNAL OF RADIATION RESEARCH ( OXFORD UNIV PRESS ) 55 ( 6 ) 1146 - 1152 2014年11月 [査読有り]

This study sought to demonstrate the feasibility of estimating the source strength during implantation in brachytherapy. The requirement for measuring the strengths of the linked sources was investigated. The utilized sources were I-125 with air kerma strengths of 8.38-8.63 U (mu Gy m(2) h(-1)). Measurements were performed with a plastic scintillator (80 mm x 50 mm x 20 mm in thickness). For a source-to-source distance of 10.5 mm and at source speeds of up to 200 mm s(-1), a counting time of 10 ms and a detector-to-needle distance of 5 mm were found to be the appropriate measurement conditions. The combined standard uncertainty (CSU) with the coverage factor of 1 (k = 1) was similar to 15% when using a grid to decrease the interference by the neighboring sources. Without the grid, the CSU (k = 1) was similar to 5%, and an 8% overestimation due to the neighboring sources was found to potentially cause additional uncertainty. In order to improve the accuracy in estimating source strength, it is recommended that the measurment conditions should be optimized by considering the tradeoff between the overestimation due to the neighboring sources and the intensity of the measured value, which influences the random error.

DOI

Serological Surveillance Development for Tropical Infectious Diseases Using Simultaneous Microsphere-Based Multiplex Assays and Finite Mixture Models

Yoshito Fujii, Satoshi Kaneko, Samson Muuo Nzou, Matilu Mwau, Sammy M. Njenga, Chihiro Tanigawa, James Kimotho, Anne Wanjiru Mwangi, Ibrahim Kiche, Sohkichi Matsumoto, Mamiko Niki, Mayuko Osada-Oka, Yoshio Ichinose, Manabu Inoue, Makoto Itoh, Hiroshi Tachibana, Kazunari Ishii, Takafumi Tsuboi, Lay Myint Yoshida, Dinesh Mondal, Rashidul Haque, Shinjiro Hamano, Mwatasa Changoma, Tomonori Hoshi, Ken-ichi Kamo, Mohamed Karama, Masashi Miura, Kenji Hirayama

PLOS NEGLECTED TROPICAL DISEASES ( PUBLIC LIBRARY SCIENCE ) 8 ( 7 ) 1 - 15 2014年07月 [査読有り]

Background: A strategy to combat infectious diseases, including neglected tropical diseases (NTDs), will depend on the development of reliable epidemiological surveillance methods. To establish a simple and practical seroprevalence detection system, we developed a microsphere-based multiplex immunoassay system and evaluated utility using samples obtained in Kenya. Methods: We developed a microsphere-based immuno-assay system to simultaneously measure the individual levels of plasma antibody (IgG) against 8 antigens derived from 6 pathogens: Entamoeba histolytica (C-IgL), Leishmania donovani (KRP42), Toxoplasma gondii (SAG1), Wuchereria bancrofti (SXP1), HIV (gag, gp120 and gp41), and Vibrio cholerae (cholera toxin). The assay system was validated using appropriate control samples. The assay system was applied for 3411 blood samples collected from the general population randomly selected from two health and demographic surveillance system (HDSS) cohorts in the coastal and western regions of Kenya. The immunoassay values distribution for each antigen was mathematically defined by a finite mixture model, and cut-off values were optimized. Findings: Sensitivities and specificities for each antigen ranged between 71 and 100%. Seroprevalences for each pathogen from the Kwale and Mbita HDSS sites (respectively) were as follows: HIV, 3.0% and 20.1%; L. donovani, 12.6% and 17.3%; E. histolytica, 12.8% and 16.6%; and T. gondii, 30.9% and 28.2%. Seroprevalences of W. bancrofti and V. cholerae showed relatively high figures, especially among children. The results might be affected by immunological cross reactions between W. bancrofti-SXP1 and other parasitic infections; and cholera toxin and the enterotoxigenic E. coli (ETEC), respectively. Interpretation: A microsphere-based multi-serological assay system can provide an opportunity to comprehensively grasp epidemiological features for NTDs. By adding pathogens and antigens of interest, optimized made-to-order high-quality programs can be established to utilize limited resources to effectively control NTDs in Africa.

DOI

A dosimetry method for low dose rate brachytherapy by EGS5 combined with regression to reflect source strength shortage

Kenichi Tanaka, Kunihiko Tateoka, Osamu Asanuma, Ken-ichi Kamo, Kaori Sato, Hiromitsu Takeda, Masaru Takagi, Masato Hareyama, Jun Takada

JOURNAL OF RADIATION RESEARCH ( OXFORD UNIV PRESS ) 55 ( 3 ) 608 - 612 2014年05月 [査読有り]

The post-implantation dosimetry for brachytherapy using Monte Carlo calculation by EGS5 code combined with the source strength regression was investigated with respect to its validity. In this method, the source strength for the EGS5 calculation was adjusted with the regression, so that the calculation would reproduce the dose monitored with the glass rod dosimeters (GRDs) on a water phantom. The experiments were performed, simulating the case where one of two I-125 sources of Oncoseed 6711 was lacking strength by 4-48%. As a result, the calculation without regression was in agreement with the GRD measurement within 26-62%. In this case, the shortage in strength of a source was neglected. By the regression, in order to reflect the strength shortage, the agreement was improved up to 17-24%. This agreement was also comparable with accuracy of the dose calculation for single source geometry reported previously. These results suggest the validity of the dosimetry method proposed in this study.

DOI

Short-Term Projection of Cancer Incidence in Japan Using an AgePeriod Interaction Model with Spline Smoothing

Kota Katanoda, Ken-Ichi Kamo, Kumiko Saika, Tomohiro Matsuda, Akiko Shibata, Ayako Matsuda, Yoshikazu Nishino, Masakazu Hattori, Midori Soda, Akiko Ioka, Tomotaka Sobue, Hiroshi Nishimoto

JAPANESE JOURNAL OF CLINICAL ONCOLOGY ( OXFORD UNIV PRESS ) 44 ( 1 ) 36 - 41 2014年01月 [査読有り]

In Japan, population-based cancer incidence data are reported several years behind the latest year of cancer mortality data. To bridge this gap, we aimed to determine a short-term projection method for cancer incidence. Data between 1985 and 2007 were obtained from the population-based cancer registries in four prefectures (Miyagi, Yamagata, Fukui and Nagasaki). Three projection models were examined: generalized linear model with age and period (A P linear); generalized linear model with age, period and their interactions (AP linear); and generalized additive model with age, period and their interactions smoothed by spline (AP spline). We performed a 5-year projection for the years 2000 and 2005, based on the data of 198595 and 19852000, respectively. Seven cancer sites (stomach, liver, colorectal, lung, female breast, cervix uteri and prostate) and all cancers combined were analyzed. The accuracy of projection was evaluated by whether each observed number fell within the 95 confidence interval of the projected number. The AP spline model accurately projected 8 of 13 cancer sitesex combinations, whereas the number of sitesex combinations of accurate projection was 2 and 6 for A P linear and AP linear models, respectively. For liver and colorectal cancers, the AP spline model alone performed accurate projections; the relative differences between projected and observed numbers of cancer incidence ranged between 0.4 and 10.9 for the AP spline, and between 7.4 and 37.6 for the other two models. All three models failed to project sudden increases in prostate cancer between 2000 and 2005. The AP spline model is a candidate method for the projection of cancer incidence in Japan. However, we need a continuous validation for prostate cancer.

DOI

Measurement of the strength of iodine-125 seed moving at unknown speed during implantation in brachytherapy

Kenichi Tanaka, Satoru Endo, Kunihiko Tateoka, Osamu Asanuma, Ken-ichi Kamo, Kaori Sato, Hiromitsu Takeda, Masaru Takagi, Masato Hareyama, Jun Takada

JOURNAL OF RADIATION RESEARCH ( OXFORD UNIV PRESS ) 55 ( 1 ) 162 - 167 2014年01月 [査読有り]

The aim of this study is to demonstrate the feasibility of estimating the strength of the moving radiation source during patient implantation. The requirement for the counting time was investigated by comparing the results of the measurements for the static source with those for the source moving at 2, 5, 10 and 20 cm s(-1). The utilized source was I-125 with an air-kerma strength of 0.432 U (mu Gym(2)h(-1)). The detector utilized was a plastic scintillation detector (8 cm x 5 cm x 2 cm in thickness) set at 8 cm away from the needle to guide the source. Experiments were conducted in order to determine the most desirable counting time. Analysis using the maximum of the measured values while the source passed through the needle indicated that the results for the moving source increased more than those for the static source as the counting time decreased. The combined standard uncertainty, with the coverage factor of 1, was within 4% at the counting time of 100 ms. This investigation supported the feasibility of the method proposed for estimating the source strength during the implantation procedure, regardless of the source speed. The method proposed is a potential option for reducing the risk of accidental replacements of sources with those of incorrect strengths.

DOI

Benchmark of EGS5 for 125I brachytherapy

K.Tanaka, K.Tateoka, O.Asanuma, K.Kamo, K.Sato, H.Takeda, M.Takagi, M.Hareyama, J.Takada

Progress in Nuclear Science and Technology 4 888 - 890 2014年 [査読有り]

DOI

Bias-corrected AIC for selecting variables in poisson regression models

Ken-Ichi Kamo, Hirokazu Yanagihara, Kenichi Satoh

Communications in Statistics - Theory and Methods 42 ( 11 ) 1911 - 1921 2013年06月 [査読有り]

担当区分：筆頭著者 , 責任著者

In the present article, we consider the variable selection problem in Poisson regression models. Akaike's information criterion (AIC) is the most commonly applied criterion for selecting variables. However, the bias of the AIC cannot be ignored, especially in small samples. We herein propose a new bias-corrected version of the AIC that is constructed by stochastic expansion of the maximum likelihood estimator. The proposed information criterion can reduce the bias of the AIC from O(n-1) to O(n-2). The results of numerical investigations indicate that the proposed criterion is better than the AIC. © 2013 Taylor & Francis Group, LLC.

DOI

Comparative analysis on selecting growth function based on three different information criteria for the purpose of carbon estimation

Ken-Ichi Kamo, Atsushi Yoshimoto

Forest Science and Technology 9 ( 2 ) 65 - 71 2013年06月 [査読有り]

担当区分：筆頭著者 , 責任著者

Growth models are in general constructed by some kind of mathematical function, so-called "growth function". Since there are several possible growth functions, the first task for the growth analysis is to select the most suitable growth function for the target data among candidates. In this paper, three statistical procedures are presented and compared on the basis of the information criterion for the purpose of selecting a growth function. A demonstrative example is provided to show how the three statistical procedures differ and select different growth functions for the same growth data, and how differently the amount of carbon sequestrated in a forest stand is affected by the selected growth function. © 2013 Copyright Taylor and Francis Group, LLC.

DOI

Comparative analysis of growth functions based on Mallows’ Cp type criterion

K.Kamo, A.Yoshimoto

Forest Resource Management and Mathematical Modeling 12 133 - 147 2013年 [査読有り]

担当区分：筆頭著者 , 責任著者

DOI

離散データに対する回帰モデルによる冠雪害の解析

加茂憲一, 嘉戸昭夫, 吉本敦

統計数理 ( 統計数理研究所 ) 61 ( 2 ) 189 - 200 2013年 [査読有り]

担当区分：筆頭著者 , 責任著者

CiNii

Clinical and genetic analysis of microtia in Japan

Makoto Yamauchi, Takatoshi Yotsuyanagi, Kanae Ikeda, Mayu Yoshikawa, Satoshi Urushidate, Makoto Mikami, Kenichi Kamo

JOURNAL OF PLASTIC SURGERY AND HAND SURGERY ( INFORMA HEALTHCARE ) 46 ( 5 ) 330 - 334 2012年10月 [査読有り]

担当区分：最終著者

Microtia is thought to have a multifactorial inheritance, but several investigators disagree. Here we report our survey of the hereditary factors and possible causes. We conducted a questionnaire survey of 428 patients with microtia who were being treated at two hospitals from September 2006 to September 2008. We recorded their age, sex, affected side, duration of gestation, birth weight, age of parents at patients' birth, accompanying malformations, number of siblings, familial occurrence, smoking habit of parents, and medication/disorders of mother during pregnancy, and analysed the results. There were preponderances of male (61%), unilateral (90%) and right-sided disease (59%). Other than the first and second branchial arch syndrome, microtia is often accompanied by other congenital deformities, in particular congenital heart disease; cleft lip, or palate, or both; vertebral defects; and anomalies of extremities. The occurrence in first-degree relatives was 2%. Most maternal disorders and medication taken during pregnancy were common and there was no clear link. Statistically, there was a tendency to low birth weight and high maternal age, but it is not possible to identify these as a specific cause of microtia. Multifactorial inheritance is unlikely to be the cause of microtia as there was only one finding in agreement with its widely accepted characteristics. However, we cannot completely discount it as there were too few cases in some groups to make a judgement.

DOI

Bias-corrected AIC for selecting variables in multinomial logistic regression models

Hirokazu Yanagihara, Ken-ichi Kamo, Shinpei Imori, Kenichi Satoh

LINEAR ALGEBRA AND ITS APPLICATIONS ( ELSEVIER SCIENCE INC ) 436 ( 11 ) 4329 - 4341 2012年06月 [査読有り]

In this paper, we consider the bias correction of Akaike's information criterion (AIC) for selecting variables in multinomial logistic regression models. For simplifying a formula of the bias-corrected AIC, we calculate the bias of the AIC to a risk function through the expectations of partial derivatives of the negative log-likelihood function. As a result, we can express the bias correction term of the bias-corrected AIC with only three matrices consisting of the second, third, and fourth derivatives of the negative log-likelihood function. By conducting numerical studies, we verify that the proposed bias-corrected AIC performs better than the crude AIC. (C) 2012 Elsevier Inc. All rights reserved.

DOI

MEM spectral analysis for predicting influenza epidemics in Japan

Ayako Sumi, Ken-Ichi Kamo

Environmental Health and Preventive Medicine 17 ( 2 ) 98 - 108 2012年03月 [査読有り]

担当区分：最終著者

Objectives The prediction of influenza epidemics has long been the focus of attention in epidemiology and mathematical biology. In this study, we tested whether time series analysis was useful for predicting the incidence of influenza in Japan. Methods The method of time series analysis we used consists of spectral analysis based on the maximum entropy method (MEM) in the frequency domain and the nonlinear least squares method in the time domain. Using this time series analysis, we analyzed the incidence data of influenza in Japan from January 1948 to December 1998 these data are unique in that they covered the periods of pandemics in Japan in 1957, 1968, and 1977. Results On the basis of the MEM spectral analysis, we identified the periodic modes explaining the underlying variations of the incidence data. The optimum least squares fitting (LSF) curve calculated with the periodic modes reproduced the underlying variation of the incidence data. An extension of the LSF curve could be used to predict the incidence of influenza quantitatively. Conclusions Our study suggested that MEM spectral analysis would allow us to model temporal variations of influenza epidemics with multiple periodic modes much more effectively than by using the method of conventional time series analysis, which has been used previously to investigate the behavior of temporal variations in influenza data. © The Japanese Society for Hygiene 2011.

DOI PubMed

Cancer Incidence and Incidence Rates in Japan in 2006: Based on Data from 15 Population-based Cancer Registries in the Monitoring of Cancer Incidence in Japan (MCIJ) Project

Tomohiro Matsuda, Tomomi Marugame, Ken-ichi Kamo, Kota Katanoda, Wakiko Ajiki, Tomotaka Sobue

JAPANESE JOURNAL OF CLINICAL ONCOLOGY ( OXFORD UNIV PRESS ) 42 ( 2 ) 139 - 147 2012年02月 [査読有り]

The Japan Cancer Surveillance Research Group estimated the cancer incidence in 2006 as part of the Monitoring of Cancer Incidence in Japan (MCIJ) project, on the basis of data collected from 15 of 32 population-based cancer registries. The total number of incidences in Japan for 2006 was estimated as 664 398 (C00-C96). The leading cancer site was stomach for men and breast for women. Age-standardized incidence rates remained at almost the same level as for the previous 3 years.

DOI

Verification of dose calculation for brachytherapy using EGS5

K. Tanaka, K. Tateoka, O. Asanuma, K. Kamo, K. Sato, H. Takeda, M. Takagi, M. Hareyama, J. Takada

Proceedings of the 19th EGS Users' Meeting in Japan 94 - 97 2012年

The dose obtained from measurement with a radiophotoluminescent glass rod dosimeter (GRD) was compared to the dose calculated with the Monte Carlo (MC) code 'EGS5,' using 125I source structures for model STM1251 and Oncoceed 6711. Some of the GRD positions were so close to the phantom surface that the backscatter margin was less than 5 cm, insufficient for photons. Consequently, the agreement between the MC calculation and GRD measurement support the validity of both methods.

Survival analysis and tree failure: Results from a tree-pulling experiment

Kamo Kenichi

Forest Resource Management and Mathematical Modeling 11 195 - 209 2012年 [査読有り]

担当区分：筆頭著者 , 責任著者

Nonlinear oscillations of fourth order quasilinear ordinary differential equations

K. Kamo, H. Usami

ACTA MATHEMATICA HUNGARICA ( SPRINGER ) 132 ( 3 ) 207 - 222 2011年08月 [査読有り]

担当区分：筆頭著者 , 責任著者

We consider fourth order quasilinear ordinary differential equations. Firstly, we classify positive solutions into four types according to their asymptotic properties. Then we derive existence theorems of positive solutions belonging to each type. Using these results, we can obtain an oscillation criterion, which is our main objective. Moreover, applying such criteria for ordinary differential equations to binary elliptic systems, we establish nonexistence theorems for positive solutions.

DOI

A dosimetry study of the Oncoseed 6711 using glass rod dosimeters and EGS5 Monte Carlo code in a geometry lacking radiation equilibrium scatter conditions

Kenichi Tanaka, Kunihiko Tateoka, Osamu Asanuma, Ken-ichi Kamo, Gerard Bengua, Kaori Sato, Toshikazu Ueda, Hiromitsu Takeda, Masaru Takagi, Masato Hareyama, Jun Takada

MEDICAL PHYSICS ( AMER ASSOC PHYSICISTS MEDICINE AMER INST PHYSICS ) 38 ( 6 ) 3069 - 3076 2011年06月 [査読有り]

Purpose: The aim of this study was to develop a dose calculation method which is applicable to the interseed attenuation and the geometry lacking the equilibrium radiation scatter conditions in brachytherapy. Methods: The dose obtained from measurement with a radiophotoluminescent glass rod dosimeter (GRD) was compared to the dose calculated with the Monte Carlo (MC) code "EGS5," using the (125)I source structure detailed in by Kennedy 1 The GRDs were irradiated with (125)I Oncoseed 6711 in a human head phantom. The phantom was a cylinder made of 2 mm thick PMMA with a diameter of 18 cm and length of 16 cm. Some of the GRD positions were so close to the phantom surface that the backscatter margin was less than 5 cm, insufficient for photons. Results: The EGS5 simulations were found to reproduce the relative dose distributions as measured with the GRDs to within 25% uncertainty in the geometry lacking the equilibrium radiation scatter conditions. The absolute value of the GRD measurement agreed with the American Association of Physicist in Medicine Task Group No 43 Updated Protocol (AAPM-TG43U1) formalism to within 3% of the reference point (r = 1 cm, theta = 90 degrees), where the TG43U1 is especially reliable because of the abundant data accumulation in composing the formalism. The factor to normalize the measured or calculated dose to the TG43U1 estimate at the reference point was evaluated to be 0.97 for the GRD measurement and 1.8 for the MC calculation, which uses the integration of the apparent activity with the time as the amount of disintegration during the irradiation. Also, F(r,theta) and g(r) estimated by this calculation method were consistent with those proposed in the TG43U1. Conclusions: The results of this investigation support the validity of both the MC calculation method and GRD measurement in this study as well as the TG-43U1 formalism. Also, this calculation is applicable to interseed attenuation and the geometry lacking the equilibrium radiation scatter.(C) 2011 American Association of Physicists in Medicine. [DOI: 10.1118/1.3590370]

DOI

Second-order bias-corrected AIC in multivariate normal linear models under non-normality

Hirokazu Yanagihara, Ken-Ichi Kamo, Tetsuji Tonda

CANADIAN JOURNAL OF STATISTICS-REVUE CANADIENNE DE STATISTIQUE ( WILEY-BLACKWELL PUBLISHING, INC ) 39 ( 1 ) 126 - 146 2011年03月 [査読有り]

This paper deals with a bias correction of Akaike's information criterion (AIC) for selecting variables in multivariate normal linear regression models when the true distribution of observation is an unknown non-normal distribution. It is well known that the bias of AIC is O(1), and there are a number of the first-order bias-corrected AICs which improve the bias to O(n(-1)), where n is the sample size. A new information criterion is proposed by slightly adjusting the first-order bias-corrected AIC. Although the adjustment is achieved by merely using constant coefficients, the bias of the new criterion is reduced to O(n(-2)). Then, a variance of the new criterion is also improved. Through numerical experiments, we verify that our criterion is superior to others. The Canadian Journal of Statistics 39: 126-146; 2011 (C) 2011 Statistical Society of Canada

DOI

Study on the effect of measles control programmes on periodic structures of disease epidemics in a large Chinese city

T. Luo, A. Sumi, D. Zhou, K. Kamo, B. Yu, D. Zhao, K. Mise, N. Kobayashi

EPIDEMIOLOGY AND INFECTION ( CAMBRIDGE UNIV PRESS ) 139 ( 2 ) 257 - 264 2011年02月 [査読有り]

Measles is regarded as a disease that can be eliminated by vaccination; however, disease epidemics still occur in Wuhan, China. This study explored the effect of measles control programmes on the periodic structure of disease epidemics in Wuhan. The monthly reported measles incidence from 1953 to 2008 was divided into pre-vaccine range (1953-1965) and post-vaccine range (1966-2008). For the incidence in each range, spectral analysis was conducted and power spectral density (PSD) was obtained. In PSD for the pre-vaccine range, the most dominant spectral line was observed at a 2.0-year period, as in the case of Japan. It was confirmed that spectral lines of periodic modes longer than a 1-year cycle of the incidence rates behave in response to the introduction of measles control programmes. The investigation of periodic structures of measles epidemics will contribute to effective measles control programmes in Wuhan.

DOI

Cancer Incidence and Incidence Rates in Japan in 2005: Based on Data from 12 Population-based Cancer Registries in the Monitoring of Cancer Incidence in Japan (MCIJ) Project

Tomohiro Matsuda, Tomomi Marugame, Ken-ichi Kamo, Kota Katanoda, Wakiko Ajiki, Tomotaka Sobue

JAPANESE JOURNAL OF CLINICAL ONCOLOGY ( OXFORD UNIV PRESS ) 41 ( 1 ) 139 - 147 2011年01月 [査読有り]

The Japan Cancer Surveillance Research Group estimated the cancer incidence in 2005 as part of the Monitoring of Cancer Incidence in Japan (MCIJ) project, on the basis of data collected from 12 of 30 population-based cancer registries. The total number of incidences in Japan for 2005 was estimated as 646 802 (C00-C96). The leading cancer site was the stomach for men and the breast for women. Age-standardized incidence rates remained almost the same level as the previous 2 years.

DOI

Time Series Analysis of Incidence Data of Influenza in Japan

Ayako Sumi, Ken-ichi Kamo, Norio Ohtomo, Keiji Mise, Nobumichi Kobayashi

JOURNAL OF EPIDEMIOLOGY ( JAPAN EPIDEMIOLOGICAL ASSOC ) 21 ( 1 ) 21 - 29 2011年01月 [査読有り]

Background: Much effort has been expended on interpreting the mechanism of influenza epidemics, so as to better predict them. In addition to the obvious annual cycle of influenza epidemics, longer-term incidence patterns are present. These so-called interepidemic periods have long been a focus of epidemiology. However, there has been less investigation of the interepidemic period of influenza epidemics. In the present study, we used spectral analysis of influenza morbidity records to indentify the interepidemic period of influenza epidemics in Japan. Methods: We used time series data of the monthly incidence of influenza in Japan from January 1948 through December 1998. To evaluate the incidence data, we conducted maximum entropy method (MEM) spectral analysis, which is useful in investigating the periodicities of shorter time series, such as that of the incidence data used in the present study. We also conducted a segment time series analysis and obtained a 3-dimensional spectral array. Results: Based on the results of power spectral density (PSD) obtained from MEM spectral analysis, we identified 3 periodic modes as the interepidemic periods of the incidence data. Segment time series analysis revealed that the amount of amplitude of the interepidemic periods increased during the occurrence of influenza pandemics and decreased when vaccine programs were introduced. Conclusions: The findings suggest that the temporal behavior of the interepidemic periods of influenza epidemics is correlated with the magnitude of cross-reactive immune responses.

DOI

日本におけるがん罹患率の動向

邱冬梅, 加茂憲一, 坂本なほ子

統計数理 ( 統計数理研究所 ) 59 ( 2 ) 193 - 204 2011年 [査読有り]

CiNii

年齢－時代平面上における癌死亡リスクの視覚化

加茂憲一, 冨田哲治, 佐藤健一

統計数理 ( 統計数理研究所 ) 59 ( 2 ) 217 - 238 2011年 [査読有り]

担当区分：筆頭著者 , 責任著者

CiNii

Cancer Incidence and Incidence Rates in Japan in 2004: Based on Data from 14 Population-based Cancer Registries in the Monitoring of Cancer Incidence in Japan (MCIJ) Project

Tomohiro Matsuda, Tomomi Marugame, Ken-ichi Kamo, Kota Katanoda, Wakiko Ajiki, Tomotaka Sobue

JAPANESE JOURNAL OF CLINICAL ONCOLOGY ( OXFORD UNIV PRESS ) 40 ( 12 ) 1192 - 1200 2010年12月 [査読有り]

The Japan Cancer Surveillance Research Group estimated the cancer incidence in 2004 as part of the Monitoring of Cancer Incidence in Japan (MCIJ) project, on the basis of data collected from 14 of 31 population-based cancer registries. The total number of incidences in Japan for 2004 was estimated as 623 275 (C00-C96). The leading cancer site according to the crude and age-standardized incidence rates was the stomach for men and breast for women. The apparent increase in age-standardized incidence rates in 2003 was calmed down in 2004.

DOI

Characterization of slowly decaying positive solutions of second-order quasilinear ordinary differential equations with sub-homogeneity

Ken-ichi Kamo, Hiroyuki Usami

BULLETIN OF THE LONDON MATHEMATICAL SOCIETY ( OXFORD UNIV PRESS ) 42 ( 3 ) 420 - 428 2010年06月 [査読有り]

担当区分：筆頭著者 , 責任著者

DOI

A robust estimation method for a growth curve model with balanced design

K.Satoh, H.Yanagihara, K.Kamo

Advanced in Theory and Applications 3 ( 2 ) 113 - 124 2010年 [査読有り]

担当区分：最終著者

Estimation of cancer incidence in Japan with an age-period-cohort model

M.Utada, Y, Ohno, M.Soda, K.Kamo

Asian Pacific Journal of Cancer Prevention 11 ( 5 ) 1235 - 1240 2010年 [査読有り]

担当区分：最終著者

Cancer Incidence and Incidence Rates in Japan in 2003: Based on Data from 13 Population-based Cancer Registries in the Monitoring of Cancer Incidence in Japan (MCIJ) Project

Tomohiro Matsuda, Tomomi Marugame, Ken-ichi Kamo, Kota Katanoda, Wakiko Ajiki, Tomotaka Sobue

JAPANESE JOURNAL OF CLINICAL ONCOLOGY ( OXFORD UNIV PRESS ) 39 ( 12 ) 850 - 858 2009年12月 [査読有り]

DOI

2003年データに基づく、生涯がん罹患・死亡リスク推定(Lifetime probability of developing or dying of cancer in 2003)

加茂憲一, 片野田耕太, 松田智大, 丸亀知美, 味木和喜子, 祖父江友孝

日本癌学会総会記事 ( (一社)日本癌学会 ) 68回 507 - 507 2009年08月

離散分布の経時測定データにおける線形な変化係数の推測について

佐藤健一, 柳原宏和, 加茂憲一

応用統計学 ( Japanese Society of Applied Statistics ) 38 ( 1 ) 19 - 28 2009年 [査読有り]

担当区分：最終著者

回帰モデルにおいて，変化係数は時間とともに変化する説明変数の効果を評価でき，視覚的にも理解しやすいために広く利用されるようになってきた．その推定値は固定された時間ごとに近傍データを用いて回帰をすることで容易に得られる．しかしながら，時間についての連続性がないために観測時間を通した曲線としての信頼区間の構成および検定に困難があった．本稿ではSatoh and Yanagihara (2008) で提案された連続分布の経時測定データにおける線形な変化係数に関する推測方法を，成長曲線モデルおよび変量効果モデルとの関連を述べながら，一般化推定方程式を利用し離散分布に適用することを試みる．この手法の利点のひとつとして汎用的なソフトウェアを利用して計算できることが挙げられる．解析例ではロジスティック回帰モデルにおける変化係数の推定を紹介する．

DOI CiNii

Logistic regression model and model selection for estimating the risk of natural disaster

K.Kamo, H.Yanagihara, A.Kato, A.Yoshimoto

Forest Resource Management and Mathematical Modeling ( FORMATH Research Group ) 8 137 - 152 2009年 [査読有り]

担当区分：筆頭著者 , 責任著者

DOI

Positive unbounded solutions of second order quasilinear ordinary differential equations and their application to elliptic problems

Ken-Ichi Kamo, Hiroyuki Usami

Czechoslovak Mathematical Journal 58 ( 4 ) 1153 - 1165 2008年12月 [査読有り]

担当区分：筆頭著者 , 責任著者

DOI

生命表法による、がん罹患・死亡リスク推定

加茂憲一, 片野田耕太, 松田智大, 丸亀知美, 味木和喜子, 祖父江友孝

日本公衆衛生学会総会抄録集 ( 日本公衆衛生学会 ) 67回 223 - 223 2008年10月

Cancer incidence and incidence rates in Japan in 2002: Based on data from 11 population-based cancer registries

Tomohiro Matsuda, Tomomi Marugame, Ken-ichi Kamo, Kota Katanoda, Wakiko Ajiki, Tomotaka Sobue

JAPANESE JOURNAL OF CLINICAL ONCOLOGY ( OXFORD UNIV PRESS ) 38 ( 9 ) 641 - 648 2008年09月 [査読有り]

DOI

回帰モデルによるがん罹患数全国推定(Estimate of nation-wide cancer incidence by regression model)

加茂憲一, 片野田耕太, 松田智大, 丸亀知美, 味木和喜子, 祖父江友孝

日本癌学会総会記事 ( (一社)日本癌学会 ) 67回 378 - 378 2008年09月

Lifetime and age-conditional probabilities of developing or dying of cancer in Japan

Ken-ichi Kamo, Kota Katanoda, Tomohiro Matsuda, Tomomi Marugame, Wakiko Ajiki, Tomotaka Sobue

JAPANESE JOURNAL OF CLINICAL ONCOLOGY ( OXFORD UNIV PRESS ) 38 ( 8 ) 571 - 576 2008年08月 [査読有り]

担当区分：筆頭著者 , 責任著者

The concepts of lifetime and age-conditional probabilities of developing and dying of cancer are introduced as indexes to understand the risk of cancer. In this paper, we estimated the lifetime and age-conditional probabilities of developing and dying of cancer in 2001 and 2005, respectively, in Japan. It is estimated that one in two Japanese males and one in three females will develop cancer, and one in four Japanese males and one in six females will die of cancer. Moreover, the probabilities of developing cancer within specific decades of age are obtained as the short-term risks.

DOI

【胃癌基礎・臨床研究のアップデート】疫学研究 '地域がん登録'に基づく胃がん登録率の状況と課題

加茂憲一, 片野田耕太

日本臨床 ( (株)日本臨床社 ) 66 ( 増刊5 胃癌 ) 57 - 61 2008年07月

担当区分：筆頭著者

Asymptotic forms of positive solutions of quasilinear ordinary differential equations with singular nonlinearities

Ken-ichi Kamo, Hiroyuki Usami

NONLINEAR ANALYSIS-THEORY METHODS & APPLICATIONS ( PERGAMON-ELSEVIER SCIENCE LTD ) 68 ( 6 ) 1627 - 1639 2008年03月 [査読有り]

担当区分：筆頭著者 , 責任著者

DOI

Probability estimation of snow damage on sugi (Cryptomeria japonica) forest stands by logistic regression model in Toyama prefecture, Japan

K.Kamo, H.Yanagihara, A.Kato, A.Yoshimoto

Journal of Forest Science 24 ( 3 ) 125 - 130 2008年 [査読有り]

Cancer incidence and incidence rates in Japan in 2001 based on the data from 10 population-based cancer registries

Tomomi Marugame, Tomohiro Matsuda, Ken-Ichi Kamo, Kota Katanoda, Wakiko Ajiki, Tomotaka Sobue

JAPANESE JOURNAL OF CLINICAL ONCOLOGY ( OXFORD UNIV PRESS ) 37 ( 11 ) 884 - 891 2007年11月 [査読有り]

DOI

全国罹患数推定方法の比較(Comparison of method estimating nation-wide cancer incidence)

加茂憲一, 丸亀知美, 片野田耕太, 松田智大, 平林由香, 味木和喜子, 祖父江友孝

日本癌学会総会記事 ( (一社)日本癌学会 ) 66回 515 - 515 2007年08月

15地域がん登録1993-2002年累積データに基づく悪性軟部腫瘍罹患の状況(Incidence patterns of soft tissue sarcoma in Japan from Japan population-based cancer registry in 1993-2002)

片野田耕太, 丸亀知美, 松田智大, 平林由香, 加茂憲一, 味木和喜子, 祖父江友孝

日本癌学会総会記事 ( (一社)日本癌学会 ) 66回 516 - 516 2007年08月

The Japan cancer surveillance report: Incidence of childhood, bone, penis and testis cancers

Tomomi Marugame, Kota Katanoda, Tomohiro Matsuda, Yuka Hirabayashi, Ken-ichi Kamo, Wakiko Ajiki, Tomotaka Sobue

JAPANESE JOURNAL OF CLINICAL ONCOLOGY ( OXFORD UNIV PRESS ) 37 ( 4 ) 319 - 323 2007年04月 [査読有り]

DOI

A mathematical estimation of true cancer incidence using data from population-based cancer registries

Ken-ichi Kamo, Satoshi Kaneko, Kenichi Satoh, Hirokazu Yanagihara, Shoichi Mizuno, Tomotaka Sobue

JAPANESE JOURNAL OF CLINICAL ONCOLOGY ( OXFORD UNIV PRESS ) 37 ( 2 ) 150 - 155 2007年02月 [査読有り]

担当区分：筆頭著者 , 責任著者

Background: Accurate cancer incidence data are needed to plan, monitor and evaluate national cancer control programs. In Japan, however, such information is not available owing to incomplete cancer registries. In order to attain incidence estimation adjusted to account for this incomplete information, we have developed a new method. Methods: We developed a nonlinear regression model between observed incidence/mortality ratios and proportions of death certificate notification to observed incidence in various cancer registries. This model enables us to obtain the 'true incidence/mortality ratio', which, in the regression curve, is at zero point for the proportion of death certificate notifications. This is an ideal registration state without any missing cases. By multiplying it by the number of cancer mortalities from the National Vital Statistics, corrected cancer incidence can be estimated. Results: Applying this method for the estimation of the Japanese cancer incidence in 1997, we obtained the 'true incidence/mortality ratios' of 2.074 for men and 2.587 for women. Cancer incidences in Japan for 1997 were thus estimated to be 346 000 for men and 280 000 for women. Conclusions: A new method is proposed to estimate the national cancer incidence after adjusting for completeness of cancer registries. This method enables us to more accurately estimate the cancer incidence in a country where several cancer registries exist with various degrees of completeness of registration.

DOI

ASYMPTOTIC FORMS OF WEAKLY INCREASING POSITIVE SOLUTIONS FOR QUASILINEAR ORDINARY DIFFERENTIAL EQUATIONS

Ken-Ichi Kamo, Hiroyuki Usami

ELECTRONIC JOURNAL OF DIFFERENTIAL EQUATIONS ( TEXAS STATE UNIV ) 126 1 - 12 2007年 [査読有り]

担当区分：筆頭著者 , 責任著者

Study of the effect of vaccination on periodic structures of measles epidemics in Japan

Ayako Sumi, Ken-ichi Kam, Norio Ohtomo, Nobumichi Kobayashi

MICROBIOLOGY AND IMMUNOLOGY ( CENTER ACADEMIC PUBL JAPAN ) 51 ( 9 ) 805 - 814 2007年 [査読有り]

The purpose of this paper is to investigate the effect of vaccination on periodic structures of measles epidemics in Japan. We carried out spectral analysis for time series data of measles notifications collected in Japan. It was confirmed that the interepidemic period, which corresponds to the interval between major epidemics of measles, increases as the vaccination ratio increases. This result was supported by a theory based on a mathematical model for epidemics of infectious diseases. It was suggested that the interepidernic period is useful to estimate the effect of vaccination on measles incidences quantitatively.

Cancer incidence and incidence rates in Japan in 2000: Estimates based on data from 11 population-based cancer registries

Tomomi Marugame, Ken-Ichi Kamo, Kota Katanoda, Wakiko Ajiki, Tomotaka Sobue

JAPANESE JOURNAL OF CLINICAL ONCOLOGY ( OXFORD UNIV PRESS ) 36 ( 10 ) 668 - 675 2006年10月 [査読有り]

DOI

地域がん登録に基づく全国罹患数推定値の登録率

加茂憲一, 丸亀知美, 片野田耕太, 味木和喜子, 祖父江友孝

日本癌学会総会記事 ( (一社)日本癌学会 ) 65回 286 - 286 2006年09月

15地域がん登録1993-2001年累積データに基づく若年層(15-39歳)のがん罹患の検討

丸亀知美, 片野田耕太, 松田智大, 加茂憲一, 味木和喜子, 祖父江友孝

日本癌学会総会記事 ( (一社)日本癌学会 ) 65回 524 - 524 2006年09月

15地域がん登録1993-2001年累積データに基づく口唇・口腔・咽頭がん罹患の状況

片野田耕太, 丸亀知美, 松田智大, 加茂憲一, 味木和喜子, 祖父江友孝

日本癌学会総会記事 ( (一社)日本癌学会 ) 65回 524 - 524 2006年09月

Trends in smoking by birth cohorts born between 1900 and 1977 in Japan

T Marugame, K Kamo, T Sobue, S Akiba, S Mizuno, H Satoh, T Suzuki, K Tajima, A Tamakoshi, S Tsugane

PREVENTIVE MEDICINE ( ACADEMIC PRESS INC ELSEVIER SCIENCE ) 42 ( 2 ) 120 - 127 2006年02月 [査読有り]

Background. The present study aimed to elucidate the changing patterns of smoking among successive birth cohorts in Japan. Methods. Birth-cohort-specific smoking prevalence was estimated for birth cohorts bom from 1900 to 1952, using data pooled from four prospective studies (242,330 men and 274,075 women), and for birth cohorts bom from 1925 to 1977, using National Nutrition Survey data. Results. For men, two peaks were observed in smoking prevalence, in the 1925 and late-1950s birth cohorts, while a trough was observed for the 1938 birth cohort. For women, ever smoking prevalence was lowest among the 1930s birth cohorts. After the female 1940s birth cohorts, no peak was observed until the end of our observations, the 1970s birth cohorts. Although Japanese women have historically tended to start smoking at later ages, recently, smoking habits have widely expanded among females in young birth cohorts. Conclusions. Smoking trends in Japanese men and women vary by birth cohorts. Smoking cessation should continue to be strongly promoted among men, although the younger generation has widely adopted a nonsmoking lifestyle. For women, efforts for preventing the onset of smoking, while necessary among the younger generation, should even be enhanced among middle-aged women. (c) 2005 Elsevier Inc. All rights reserved.

DOI

日本におけるがん生涯リスク評価

加茂憲一, 金子聰, 吉村公雄, 祖父江友孝

厚生の指標 ( (一財)厚生労働統計協会 ) 52 ( 6 ) 21 - 26 2005年06月 [査読有り]

担当区分：筆頭著者 , 責任著者

わが国における生涯がん罹患(死亡)リスクと,年齢を限定しての累積リスクを推定した.生涯がん罹患(死亡)リスクとは,一生涯のうちにがんに罹患(死亡)する確率の推定値である.また年齢を限定しての累積リスクとは,がん未発症年齢と到達年齢を限定しての罹患(死亡)確率の推定値である.1999年の生涯リスクから,男性の約半分,女性の3人に1人ががんに罹患し,男性の3人に1人,女性の4人に1人ががんにより死亡する.経年的にも生涯リスクは増加し,この指標により今日のがんリスクの高さが直感的でとらえやすい形になったと考えられる.がん未発症年齢と到達年齢を限定してのリスク表から今後のリスクの変遷を知ることができる点も,国民にとってこの指標はリスクを直感的に認識しやすいものにしたと考えられた

Trends in lung cancer mortality among young adults in Japan

T Marugame, Yoshimi, I, K Kamo, Y Imamura, S Kaneko, S Mizuno, T Sobue

JAPANESE JOURNAL OF CLINICAL ONCOLOGY ( OXFORD UNIV PRESS ) 35 ( 4 ) 177 - 180 2005年04月

Background: Trends in lung cancer mortality among young adults, which are important for projecting future trends, have not been explored previously in Japan. Methods: Using data from the National Vital Statistics between 1958 and 2003, we compiled lung cancer mortality by sex and 5-year birth cohort among young adults aged 20-49. Results: Mortality among those aged 20-29 has consistently decreased regardless of sex. There were birth cohort effects in mortality from lung cancer, although these were less evident among women than among men. Both men and women born in the 1930s had lower mortality rates, while those born after 1940 had higher lung cancer mortality rates. Mortality rates appear to be declining for male birth cohorts born after 1950 and female birth cohorts after 1960, although these trends may not be stable due to the small number of deaths in these cohorts. Conclusion: Lung cancer mortality trends appear to be decreasing among young adults. This might be associated with the lower mortality of birth cohorts after 1950 for men and the 1960s birth cohorts for women. Careful monitoring is needed to confirm continuation of these declining trends.

DOI PubMed CiNii

わが国の出生コホート別喫煙割合の推移

丸亀知美, 加茂憲一, 祖父江友孝, 秋葉澄伯, 水野正一, 玉腰暁子, 佐藤洋, 鈴木隆一郎, 田島和雄, 津金昌一郎

日本癌学会総会記事 ( (一社)日本癌学会 ) 63回 542 - 542 2004年09月

Mortality trend of prostate, breast, uterus, ovary, bladder and "kidney and other urinar tract" cancer in Japan by birth cohort

K Kamo, T Sobue

JAPANESE JOURNAL OF CLINICAL ONCOLOGY ( OXFORD UNIV PRESS ) 34 ( 9 ) 561 - 563 2004年09月

DOI

Cancer statistics digest

Ken-Ichi Kamo, Tomotaka Sobue

Japanese Journal of Clinical Oncology 34 ( 9 ) 561 - 563 2004年09月 [査読有り]

DOI PubMed

Mortality trend for 'oral cavity and pharynx' and 'larynx' cancer in Japan: 1960-2000

KI Kamo, T Sobue

JAPANESE JOURNAL OF CLINICAL ONCOLOGY ( OXFORD UNIV PRESS ) 34 ( 3 ) 162 - 164 2004年03月

Asymptotic equivalence for positive decaying solutions of the generalized Emden-Fowler equations and its applications to elliptic problems

K.Kamo

Archivum mathematicum 2004年

担当区分：筆頭著者 , 責任著者

Projection of lung cancer mortality in Japan

S Kaneko, KB Ishikawa, Yoshimi, I, T Marugame, C Hamashima, K Kamo, S Mizuno, T Sobue

CANCER SCIENCE ( JAPANESE CANCER ASSOC ) 94 ( 10 ) 919 - 923 2003年10月

According to the National Vital Statistics data, age-standardized mortality rates (ASRs) of lung cancer have shown slightly declining trends in Japan for both men and women. in order to evaluate whether this tendency will continue, a Bayesian age-period-cohort (APC) model was applied using the National Vital Statistics data from 1952 to 2001. In the projection, a Gaussian autoregressive prior model was applied to smooth age, period, and cohort effects from its 2 immediate predecessors by extrapolation. Posterior distributions from which we drew inferences on mortality rates were derived from 15,000 iterations using 5000 burn-in iterations. We defined the median of the iterated values as the overall summary mortality rate of the iterated results. Our results suggest that the number of deaths due to lung cancer will double for men and women during the next 3 decades due to the aging of the baby-boomer generation (individuals who were born between 1947 and 1951). Currently declining trends in some age groups will reverse and start to increase again in the next decades. However, for recent birth cohorts, the results of the projection varied according to whether the data set included early age group mortality or not. Lung cancer mortality in the future depends on the risk factors engaged in by today's young people, especially smoking. Strong promotion of anti-smoking measures and careful surveillance for lung cancer are needed.

DOI PubMed

Asymptotic forms of positive solutions of third-order Emden-Fowler equations

K Kamo, H Usami

JOURNAL OF MATHEMATICAL ANALYSIS AND APPLICATIONS ( ACADEMIC PRESS INC ELSEVIER SCIENCE ) 271 ( 2 ) 297 - 312 2002年07月

担当区分：筆頭著者 , 責任著者

Oscillation theorems for fourth-order quasilinear ordinary differential equations

K-I. Kamo, H. Usami

STUDIA SCIENTIARUM MATHEMATICARUM HUNGARICA ( AKADEMIAI KIADO ) 39 ( 3-4 ) 385 - 406 2002年 [査読有り]

Asymptotic forms of positive solutions of second-order quasilinear ordinary differential equations

K.Kamo, H.Usami

Advanced in Mathematical Sciences and Applications 10 673 - 688 2000年

担当区分：筆頭著者 , 責任著者

Classification of proper solutions of some Emden-Fowler equations

KAMO Ken-ichi

Hiroshima mathematical journal ( 広島大学 ) 29 ( 3 ) 459 - 477 1999年

担当区分：筆頭著者 , 責任著者

CiNii

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