Associations Between Diabetes, Leanness, and the Risk of Death in the Japanese General Population: The Jichi Medical School Cohort Study

OBJECTIVE: To examine the BMI-stratified associations between diabetes and the risks of all-cause death, cardiovascular disease (CVD) death, and cancer death. RESEARCH DESIGN AND METHODS: Using a prospective study with 12 rural Japanese general populations (n = 3,641, mean age, 53.7 years; 33.5% men), we examined the associations between diabetes and the risk of all-cause death, CVD death, and cancer death. We also examined the effects of BMI and age on such associations. RESULTS: During an average duration of 10.2 years (37,278 person-years), 240 deaths occurred (54 deaths from CVD, 101 from cancer, and 85 from other causes). Cox regression analysis showed leanness (defined as the lowest quartile of entire BMI; mean, 19.5 kg/m(2)), but not obesity (BMI ≥25 kg/m(2)), and diabetes were independently associated with an increased risk of all-cause death (hazard ratio [HR] 1.70 and 1.65, respectively; both P < 0.01.). Stratification with cause-specific deaths showed that leanness and obesity were associated with CVD death (HR 3.77 and 2.94, respectively), whereas diabetes was associated with cancer death (HR 1.87; all P < 0.05). The increased risk of all-cause death in diabetes was substantially higher in lean subjects aged <65 years (HR 3.4) or those aged ≥65 years (HR 4.2), whereas the risk in obese diabetes patients was significant only in subjects aged <65 years (HR 2.32; all P < 0.05). CONCLUSIONS: Among the Japanese general population, diabetes confers an increased risk of all-cause death. Particular attention must be paid to the pronounced high mortality in diabetes accompanied with leanness, regardless of age.