Changes in BMI, duration of overweight and obesity, and glucose metabolism: 45 Years of follow-up of a birth cohort

Abstract

OBJECTIVE - Long-term implications of childhood obesity and BMI change over the life course for risk of type 2 diabetes remain uncertain. The objective was to establish whether there are effects on adult glucose metabolism of 1) sensitive periods of BMI gain or 2) long duration of overweight and obesity. RESEARCH DESIGN AND METHODS - Participants in the 1958 British birth cohort with child to adult BMI and glycosylated hemoglobin (HbA 1c) at 45 years (n = 7,855). RESULTS - Prevalence of type 2 diabetes or HbA 1c ≥7 was 2%. BMI gains in child- and adulthood were associated with higher HbA 1c: for every SD of 5-year BMI increase from 0 to 7 years, there was a 75% (95% CI 1.42-2.16) increased risk of HbA 1c ≥7, increasing to a 4.7-fold (3.12-7.00) risk for the interval 23-33 years. Associations for BMI gain in adulthoodwere related to attained BMI but were independent for the longer period birth (or 7 years) to 45 years. Duration of obesity was also associated with HbA 1c; compared with the never obese, those with childhood onset had a 23.9-fold risk (13.5-42.1) of HbA 1c ≥7%; odds ratios were 16.0 (10.6-24.2) and 2.99 (1.77-5.03), respectively, for young and midadulthood onset. Similar trends by onset age were found in mean HbA 1c levels and for onset of overweight. Those with the earliest age of onset had higher BMI and waist circumference at 45 years, which markedly explained the associations for onset age and HbA 1c. CONCLUSIONS - Excessive BMI gain across the life span and earlier onset of overweight/ obesity are associated with impaired glucose metabolism, in part through attained adult BMI. © 2011 by the American Diabetes Association.