title: Body mass index and the risk of cancer incidence in patients with type 2 diabetes in Japan: Results from the National Center Diabetes Database.
abstract: OBJECTIVE
  Both type 2 diabetes and obesity increase the risk of some types of cancers, and underlying mechanisms are thought to be, at least in part, common. In the present study, we carried out a retrospective cohort study of the relationship between body mass index (BMI) categories and cancer development in Japanese type 2 diabetic patients.
  
  
  METHODS
  A total of 113 incident cancers including 35 cancers whose incidence was reported to be increased by obesity (27 colorectal cancers, two breast cancers in postmenopausal women, one endometrial cancer, four renal cancers and one gallbladder cancer) were identified in 2,334 type 2 diabetic patients (1,616 men and 718 women) over an average observation period of 5.1 years.
  
  
  RESULTS
  In men, there was no significant association between the BMI categories at the start of the observation period and the development of any cancer. In contrast, the incidence of all of the cancers in the women was significantly higher in the group with a BMI of less than 22.0 kg/m2(hazard ratio 3.07, 95% CI 1.01-9.36). In either sex, there was no significant relationship between the BMI categories and the development of cancers whose risk is known to be increased by obesity.
  
  
  CONCLUSIONS
  The findings of the present study were limited by the relatively small number of patients in the cohort, which posed a danger of not finding significance. However, the results suggested that obesity did not become an additional risk factor for cancer in Japanese type 2 diabetic patients.
authors.affiliation: Research Institute, Department of Diabetes Research and Diabetes and Metabolism Information Center, Diabetes Research Center, National Center for Global Health and Medicine, Tokyo, Japan.|Health Management Center, Toranomon Hospital, Tokyo, Japan.|Department of Endocrinology and Metabolism, Toranomon Hospital, Tokyo, Japan.
authors.forename: Ritsuko
authors.initials: R
authors.lastname: Yamamoto-Honda
authors.affiliation: Research Institute, Department of Diabetes Research and Diabetes and Metabolism Information Center, Diabetes Research Center, National Center for Global Health and Medicine, Tokyo, Japan.|Division of Diabetes and Metabolism, Iwate Medical University, Morioka, Iwate, Japan.
authors.forename: Yoshihiko
authors.initials: Y
authors.lastname: Takahashi
authors.affiliation: The Institute for Adult Disease, Asahi Life Foundation, Tokyo, Japan.
authors.forename: Yoko
authors.initials: Y
authors.lastname: Yoshida
authors.affiliation: The Institute for Adult Disease, Asahi Life Foundation, Tokyo, Japan.
authors.forename: Shoji
authors.initials: S
authors.lastname: Kwazu
authors.affiliation: The Institute for Adult Disease, Asahi Life Foundation, Tokyo, Japan.
authors.forename: Yasuhiko
authors.initials: Y
authors.lastname: Iwamoto
authors.affiliation: Department of Diabetes, Endocrinology and Metabolism, National Center for Global Health and Medicine Center Hospital, Tokyo, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kajio
authors.affiliation: Department of Internal Medicine, National Center for Global Health and Medicine Kohnodai Hospital, Chiba, Japan.
authors.forename: Hidekatsu
authors.initials: H
authors.lastname: Yanai
authors.affiliation: Department of Internal Medicine, National Center for Global Health and Medicine Kohnodai Hospital, Chiba, Japan.
authors.forename: Shuichi
authors.initials: S
authors.lastname: Mishima
authors.affiliation: Ohta Nishinouchi Hospital, Fukushima, Japan.
authors.forename: Takuro
authors.initials: T
authors.lastname: Shimbo
authors.affiliation: Research Institute, Department of Diabetes Research and Diabetes and Metabolism Information Center, Diabetes Research Center, National Center for Global Health and Medicine, Tokyo, Japan. noda_m@saitama-med.ac.jp.|Department of Endocrinology and Diabetes, Saitama Medical University, Saitama, Japan. noda_m@saitama-med.ac.jp.
authors.forename: Mitsuhiko
authors.initials: M
authors.lastname: Noda
mesh_terms: D000368:Aged; D015992:Body Mass Index; D003924:Diabetes Mellitus, Type 2 / Q000150:complications / Q000453:epidemiology*; D005260:Female; D006801:Humans; D015994:Incidence; D007564:Japan; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000150:complications / Q000453:epidemiology*; D009765:Obesity / Q000150:complications / Q000453:epidemiology*; D012307:Risk Factors
keywords: Body mass index; Cancer; Type 2 diabetes