Body Mass Index and the Risk of All-Cause Mortality Among Patients With Type 2 Diabetes | Journal Scan

Study Questions:

Is there an association between body mass index (BMI) and death risk among patients with diabetes mellitus?


A cohort of 19,478 black and 15,354 white patients with type 2 diabetes mellitus was included in a prospective analysis. Cox proportional hazard regression models were used to estimate the association of different levels of BMI stratification with all-cause mortality.


During a mean follow-up of 8.7 years, 4,042 deaths were identified. The multivariable-adjusted (age, sex, smoking, income, and type of insurance) hazard ratios for all-cause mortality associated with BMI levels (18.5-22.9, 23-24.9, 25-29.9, 30-34.9 [reference group], 35-39.9, and ≥40 kg/m2) at baseline were 2.12 (95% confidence interval [CI], 1.80-2.49), 1.74 (95% CI, 1.46-2.07), 1.23 (95% CI, 1.08-1.41), 1.00, 1.19 (95% CI, 1.03-1.39), and 1.23 (95% CI, 1.05-1.43) for blacks; and 1.70 (95% CI, 1.42-2.04), 1.51 (95% CI, 1.27-1.80), 1.07 (95% CI, 0.94-1.21), 1.00, 1.07 (95% CI, 0.93-1.23), and 1.20 (95% CI, 1.05-1.38) for whites, respectively. When stratified by age, smoking status, patient type, or the use of antidiabetic drugs, a U-shaped association was still present. When BMI was included in the Cox model as a time-dependent variable, the U-shaped association of BMI with all-cause mortality risk did not change.


The present study revealed a U-shaped association between BMI and all-cause mortality risk among black and white patients with type 2 diabetes mellitus. A significantly increased risk of all-cause mortality was observed among blacks with BMI <30 kg/m2 and ≥35 kg/m2, and among whites with BMI <25 kg/m2 and ≥40 kg/m2 compared with patients with BMI of 30-34.9 kg/m2.


This is an important study that used administrative data from the Louisiana State University Health Care Services Division (which covers ~35% of the population of the state of Louisiana). It reveals a U-shaped all-cause mortality curve among patients with diabetes mellitus, with a risk nadir at ~30-35 kg/m2 for blacks and ~25-40 kg/m2 for whites. Although weight reduction should be of benefit in reducing all-cause mortality among obese patients with diabetes, this study, and others like it, raises the question of how to counsel, with respect to body weight, thin patients with diabetes.

Clinical Topics: Prevention, Smoking

Keywords: African Americans, Body Mass Index, Diabetes Mellitus, Type 2, European Continental Ancestry Group, Hypoglycemic Agents, Louisiana, Obesity, Smoking, Weight Loss

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