Quantitative relationship between body weight gain in adulthood and incident type 2 diabetes: a meta-analysis

This meta-analysis quantified the risk of type 2 diabetes mellitus (T2DM) preceded by body weight (BW) gain in the general population. Systematic literature searches retrieved 15 eligible studies. The BW gain was divided into early weight-gain, which was defined as BW gain from early adulthood (18-24 years of age) to cohort entry (≥25 years of age), and late weight-gain, which was defined as BW gain from cohort entry. The pooled relative risk (RR; 95% confidence interval [CI]) of T2DM for an increment of BW gain standardized into a 5-kg m(-2) increment in the body mass index (BMI) was 3.07 (2.49-2.79) for early weight-gain and 2.12 (1.74-2.58) for late weight-gain. When limiting analysis to studies that concurrently examined T2DM risk for current BMI (defined in both groups as BMI at cohort entry), a larger magnitude of T2DM risk was revealed for early weight-gain compared with current BMI (RR [95% CI], 3.38 [2.20-5.18] vs. 2.39 [1.58-3.62]), while there was little difference between late weight-gain (RR [95% CI], 2.21 [1.91-2.56]) and current BMI (RR [95% CI], 2.47 [1.97-3.30]). The meta-analysis suggested that BW gain was a quantifiable predictor of T2DM, as well as current obesity in adults. Particularly, BW gain in early rather than middle-to-late adulthood played an important role in developing T2DM.