Site-specific cancer risk due to diabetes mellitus history: evidence from the Japan Collaborative Cohort (JACC) Study.

The study examined the association of diabetes mellitus (DM) history with total and common site-specific cancers using a large cohort of 23,378 men and 33,503 women, extracted from 127,477 healthy participants of the JACC Study who were aged 40-79 years and living in 24 municipalities in Japan. At enrollment during 1988-90, each subject completed a self-administered questionnaire including items for age, sex, body mass index (BMI), smoking, drinking, past history of DM and cancer. Adjusting for age, BMI, smoking, and drinking in the Cox's proportional hazard model, incidence rate ratios (IRR) with 95% confidence intervals (95%CIs) were estimated for both sexes. During the follow-up period, total cancers and site-specific cancers were identified. A history of DM was reported by 7.5% of men and 4.6% of women. DM significantly increased the risk of liver cancer for both men (IRR=2.30; 95%CI=1.47-3.59) and women (IRR=2.70; 95%CI=1.20-6.05). Significant increased and reduced risk due to DM for men were also found for non-Hodgkin lymphoma (IRR=2.77; 95%CI=1.04-7.38) and stomach cancer (IRR=0.67; 95%CI=0.46-0.99) respectively. For females, a reduced risk of stomach cancer due to DM (IRR=0.49; 95%CI=0.23-1.04) was also revealed. Since a history of DM here demonstrated significant associations with some site-specific cancers, their relationships should be studied further in Japan for validation.

Risk of endometrial cancer mortality by ever-use of sex hormones and other factors in Japan.

OBJECTIVES: To examine associations of ever-use of sex hormones (EUSH) and other factors with endometrial cancer (EC) mortality through a nation-wide Japan Collaborative Cohort Study. METHODS: A total of 63,541 women aged 40-79 years, enrolled in 1988-90 from 45 municipalities of Japan, were followed until 2003 to record their vital status. Using baseline data, the Cox proportional hazard model (age adjusted and multivariate) was used to estimate the hazard ratio (HR) and 95% confidence interval (CI) for EC mortality by selected factors, including EUSH. Bivariate analysis was also conducted to establish associations between EUSH and other factors. RESULTS: The mortality rate from EC was 2.6 per 100,000 person-years during the mean follow-up period of 13.3 years. Prevalence rate of EUSH was 5.2%. Significantly increased risk of EC mortality was found for EUSH with both age adjusted (HR=6.43, 95%CI=2.10-19.67) and multivariate (HR=5.33; 95%CI=1.51-18.82) analyses. Bivariate analysis indicated that history of diabetes mellitus, smoking, drinking, and age at first delivery were positively associated with EUSH, whereas age, number of delivery, number of pregnancy, and age at menarche demonstrated inverse links. CONCLUSIONS: Our results imply that EUSH may increase the risk of EC mortality among Japanese women. However, further studies with more deaths are needed to validate the results.