Body Mass Index and the Risk of All-Cause Mortality Among Patients with Type 2 Diabetes
Background—Several prospective studies have evaluated the association between body mass index (BMI) and death risk among patients with diabetes; however, the results have been inconsistent.
Methods and Results—We performed a prospective cohort study of 19,478 African American and 15,354 white patients with type 2 diabetes. Cox proportional hazards 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 (HRs) 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 (1.46-2.07), 1.23 (1.08-1.41), 1.00, 1.19 (1.03-1.39), and 1.23 (1.05-1.43) for African Americans, and 1.70 (1.42-2.04), 1.51 (1.27-1.80), 1.07 (0.94-1.21), 1.00, 1.07 (0.93-1.23), and 1.20 (1.05-1.38) for whites, respectively. When stratified by age, smoking status, patient types or use of anti-diabetic 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.
Conclusions—The current study indicated a U-shaped association of BMI with all-cause mortality risk among African American and white patients with type 2 diabetes. A significantly increased risk of all-cause mortality was observed among African Americans with BMI<30 kg/m2 and BMI ≥35 kg/m2, and among whites with BMI<25 kg/m2 and BMI ≥40 kg/m2 compared with patients with BMI 30-34.9 kg/m2.
- Received January 30, 2014.
- Revision received September 3, 2014.
- Accepted September 26, 2014.