Adolescent BMI Trajectory and Risk of Diabetes Versus Coronary Disease
Is body mass index (BMI) measured in adolescence associated with obesity-related diseases in young adulthood?
This was a prospective analysis of apparently healthy young men who underwent periodic follow-up through the Staff Periodic Examination Center of the Israeli Army Medical Corps as part of the Metabolic, Lifestyle, and Nutrition Assessment in Young Adults (MELANY) study. Both health and weight were measured at regular intervals, with the initial measures performed when participants were 17 years of age. Men with previously diagnosed diabetes (type 1 or 2) or coronary heart disease (CHD) at adolescence were excluded. The primary outcomes of interest were incident cases of type 2 diabetes and CHD. CHD was defined as angiography-proven stenosis of more than 50% in at least one coronary artery.
A total of 37,674 participants (with approximately 650,000 person-years of follow-up) were included in this analysis. Mean follow-up was 17.4 years. The mean age at adolescence was 17.4 years, and the mean BMI ranged between 17.3 in the bottom decile to 27.6 in the top decile, corresponding to a mean weight ranging from 51.9-83.8 kg. The mean age at first assessment in adulthood was 30.6 years (median, 28.02). The mean BMI decile range in adulthood was 21.4-30.6 kg/m2. Over this time 1,173 incident cases of type 2 diabetes and 327 of CHD were documented. After adjustment for age, family history, blood pressure, lifestyle factors, and biomarkers, elevated BMI in adolescence was an independent predictor of diabetes (hazard ratio [HR], 2.76; 95% confidence interval [CI], 2.11-3.58), and angiographic-proven CHD (HR, 5.43; 95% CI, 2.77-10.62). With additional adjustment for BMI at adulthood, the association between adolescent BMI and diabetes mellitus was no longer significant (HR, 1.01; 95% CI, 0.75-1.37). However, the association between adolescent BMI and CHD remained significant (HR, 6.85; 95% CI, 3.30-14.21). When examining BMI as a continuous variable, the same relationships were observed for diabetes. In contrast, elevated BMI in both adolescence (p = 0.004) and adulthood (p = 0.03) were independently associated with angiography-proven CHD.
The investigators concluded that an elevated BMI in adolescence, including one that is well within the range currently considered to be normal, constitutes a significant risk factor for obesity-related disorders in midlife. Although the risk of diabetes is mainly associated with increased BMI close to the time of diagnosis, the risk of CHD is associated with an elevated BMI both in adolescence and in adulthood, supporting the hypothesis that the processes causing incident CHD, particularly atherosclerosis, are more gradual than those resulting in incident diabetes.
This study furthers the evidence for initiation of cardiovascular disease prevention measures early in life. A healthy lifestyle with regular physical activity is critical for prevention of elevated BMI in childhood. Health care providers need to partner with their community to improve health in children.
Keywords: Life Style, Atherosclerosis, Follow-Up Studies, Body Weight, Diabetes Mellitus, Type 2, Coronary Disease, Risk Factors, Body Mass Index, Nutrition Assessment, Motor Activity, Obesity
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