Body mass index and mortality among Japanese patients with type 2 diabetes: pooled analysis of the Japan diabetes complications study and the Japanese elderly diabetes intervention trial

J Clin Endocrinol Metab. 2014 Dec;99(12):E2692-6. doi: 10.1210/jc.2014-1855.


Context: Previous studies on the association between body mass index (BMI) and mortality in diabetes do not necessarily provide a comprehensive view in terms of the global population because of the exclusion of individuals with a BMI less than 18.5 kg/m(2).

Objective: The objective of the study was to examine the association between BMI and mortality.

Design, setting, and participants: We analyzed pooled data from 2 cohorts of 2620 Japanese patients with type 2 diabetes followed up for 6.3 years. Patients with a history of cardiovascular disease or cancer were excluded.

Main outcome measure: The end point was all-cause mortality. Hazard ratios were estimated by Cox regression adjusted for age, smoking, leisure-time physical activity, and other confounders.

Results: An analysis using BMI categories of 14.4-18.5 (5.2%), 18.5-22.4 (37.3%), 22.5-24.9 (31.0%), and 25.0-37.5 kg/m(2) (26.6%) revealed no significant trend in mortality among patients with a BMI of 18.5 kg/m(2) or greater (trend P = .69). In contrast, the hazard ratio of patients with a BMI less than 18.5 kg/m(2) vs 22.5-24.9 kg/m(2) was 2.58 (95% confidence interval 1.38-4.84; P < .01). Exclusion of deaths in the first 4 years of follow-up decreased the hazard ratio only slightly.

Conclusions: The lowest mortality rate was observed among patients with a BMI of 18.5-24.9 kg/m(2), and obesity had no benefits regarding mortality. Further research is needed in lean patients, especially among aging populations in East Asia.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Body Mass Index
  • Cohort Studies
  • Diabetes Complications / mortality*
  • Diabetes Complications / pathology*
  • Diabetes Mellitus, Type 2 / mortality*
  • Diabetes Mellitus, Type 2 / pathology*
  • Endpoint Determination
  • Female
  • Follow-Up Studies
  • Humans
  • Japan / epidemiology
  • Male
  • Middle Aged
  • Risk Factors

Associated data

  • JPRN/UMIN000000890
  • JPRN/UMINCTRC000000222