Modifying General And Central Adiposity: Estimated Effect On Population Burden Of Coronary Heart Disease. The Atherosclerosis Risk In Communities (Aric) Study

Excess adiposity, which affects 30% of the world’s population, is associated with risk of coronary heart disease (CHD), yet the potential reductions in CHD burden attainable through shifts in the population distributions of adiposity are unclear. Risk of CHD conveyed by excess adiposity is mostly mediated by the associated metabolic dysregulation, with manifestations such as hypertension and diabetes. Considering these metabolic pathways, we estimated the effect of hypothetical population reductions in general adiposity [body mass index (BMI)] or visceral adiposity [indexed by waist circumference (WC)], each consistent with lifestyle modification, on the risk of incident CHD in a US-based biracial population. The study population included 13,610 ARIC study participants aged 45-64 years, after excluding those with CHD (667) or chronic conditions associated with weight change (969) at baseline. Our hypothetical intervention reduced general adiposity (BMI) or waist circumference (WC) by 5% relative to the temporal trend observed under no intervention; the intervention was applied only among those with BMI > 24 kg/m2 (or WC>88 cm). For example, an individual who increased from a BMI of 25.2 to 27 over the study period under no intervention would increase from 24 to 25.7 following the intervention. Incident CHD was ascertained from 1987 to 2001. CHD risk differences were estimated comparing the intervention to no intervention. Over the follow-up time, 736 (BMI analysis) and 712 (WC analysis) incident CHD events occurred. For the BMI analysis, the median BMI (kg/m2) at the end of follow-up was 28.2 under no intervention and 25.6 under the hypothetical intervention. The cumulative 12-year incidence of CHD and 95% CI under no intervention was 6.3% (5.9, 6. 8%) and the risk difference following the hypothetical BMI change was -0.6% (-1.0, -0.1%). For the WC analysis, the median WC (cm) at the end of follow-up was 100.6 under no intervention and 98.3 under the hypothetical intervention. The cumulative 12-year incidence of CHD and 95% CI was 6.2% (5.8, 6. 7%) under no intervention and the risk difference following the hypothetical WC change was -1.0% (-1.4, -0.5%). Hence, 9% and 16% of CHD events occurring in this study population over 12 years could have been prevented by an annual 5% shift in BMI and WC, respectively. We estimated that meaningful reductions in CHD risk could result from modest reductions in adiposity that are consistent with what might be observed under public health efforts aimed at lifestyle modification. CHD risk reduction was larger under a hypothetical WC reduction compared to a BMI reduction, consistent with metabolic dysregulation associated with visceral adiposity. Public health messages and clinical recommendations that promote modification in WC, perhaps with reference to clothing size, would offer more concrete targets than similar messages for composite measures such as BMI.