Differential age-specific effects of LDL cholesterol and body mass index on the risk of coronary heart disease

BackgroundLow-density lipoprotein cholesterol (LDLc) and body mass index (BMI) are not always correlated and their relationship is probably dependent on age, indicating differential age-specific effects of these two factors on health outcomes. We thus aimed to discriminate the effects of LDLc and BMI on the risk of coronary heart disease (CHD) across different age groups.MethodsThis is a prospective cohort study of 368,274 participants aged 38-73 years and free of CHD at baseline. LDLc and BMI were measured at baseline, and incident CHD was the main outcome. Cox proportional hazards model and restricted cubic spline (RCS) regression were used to estimate hazard ratio (HR) and 95% confidence interval (CI) of exposure on CHD.ResultsSimilar relationships of LDLc and BMI with CHD risk were observed in overall population but in differential age-specific patterns. Across the age groups of =65 years, the LDLc-CHD association diminished with the adjusted HRs decreasing from 1.35, 1.26, 1.19, 1.11 to 1.08; while no declining trend was found in BMI-CHD relationship with the adjusted HRs of 1.15, 1.11, 1.12, 1.13 and 1.15, respectively. The interaction and mediation between LDLc and BMI on CHD risk were only present at young-age groups. And the LDLc-CHD but not BMI-CHD association was dependent on sex, metabolic syndrome and lipid-lowering drugs use.ConclusionThere were differential age-specific effects of LDLc and BMI on the risk of developing CHD, calling for future efforts to discriminate the age-different benefits from lipids management or weight control on the primary prevention for CHD.Clinical PerspectiveWhat Is New?This study shows, for the first time, that there were differential age-specific effects of LDLc and BMI on the risk of developing coronary heart disease (CHD), in which the LDLc-CHD association diminished with increasing age while no declining trend was found in BMI-CHD relationship.The interaction and mediation between LDLc and BMI on the risk of coronary heart disease were only present in young adults.What Are the Clinical Implications?Future efforts are called to discriminate the age-different benefits from lipids management or weight control on the primary prevention for CHD.Findings from this study highlighted that lipids management at young age was expected to have a much more favorable benefit in CHD prevention; and weight control shouldn’t be overlooked, especially for elderly adults, as lipid-lowering therapy might not contribute to the reduction of obesity-related CHD.