Abstract 18802: All-Cause Mortality in Normal Weight Type 2 Diabetes: A Meta-Analysis of Longitudinal Cohort Studies
Objective: Type 2 diabetes (T2DM) in normal weight (body mass index<25kg/m2) is an intriguing representation of the metabolically obese normal weight phenotype. Because the prevalence of normal weight T2DM is low (5-15% of all diabetes), no single study has had an adequate number of affected persons to study the health consequences of normal weight T2DM. We conducted a meta-analysis using 4 longitudinal cohort studies (Atherosclerosis Risk in Communities [ARIC], Cardiovascular Health Study [CHS], Coronary Artery Risk Development in Young Adults [CARDIA], and Framingham Offspring Study [FOS]) to test the hypothesis that total mortality is higher among overweight/obese persons with T2DM than persons with normal weight T2DM.
Methods: Incident T2DM was identified in each cohort as fasting glucose ≥ 126 mg/dL or newly-initiated diabetes medication use. To reduce differences in diabetes duration, normal weight was identified at the time of incident T2DM. Follow-up time was calculated as the difference between date of incident diabetes and death date. We conducted Cox proportional hazards regression separately in each cohort and pooled estimates using fixed effects meta-analysis.
Results: Participants were aged 18 to 88 years at baseline, both sexes and black and white race. There were 2262 cases of incident T2DM and the proportion of normal weight T2DM ranged from 9% (ARIC) to 21% (CHS) across cohorts. Over 26 combined years of follow-up, there were 290 deaths (13%). In an unadjusted model, the hazard ratio (HR) for mortality comparing normal weight to overweight/obese (referent) T2DM was 2.14 (95% Confidence Intervals [CI]: 1.23, 3.70). The HR in normal weight vs. overweight/obese remained elevated and statistically significant after adjustment for age, race, sex, triglycerides, HDL-cholesterol, waist circumference, systolic blood pressure and smoking status (HR=2.45, 95% CI: 1.33, 4.53).
Conclusions: Normal weight T2DM is associated with higher total mortality than overweight/obese T2DM. Comorbidity in diabetes (e.g. chronic kidney disease, cancer) may explain higher death rates in normal weight T2DM.
- © 2010 by American Heart Association, Inc.