Relationship between body regional fat and cardiovascular disease in middle-aged and young adults: Results from NHANES 2011-2018 and Mendelian randomization meta-analysis

BACKGROUNDTo assess the correlation between regional body fat and cardiovascular diseases in middle-aged and young adults. METHODSInformation on the regional body fat, including the mass and percentage of fat in the head, arms, trunk, and legs, was collected. Data for the observational study were derived from the National Health and Nutrition Examination Survey 2011-2018. The relationship between exposure and outcomes was primarily assessed using restricted cubic splines (RCS), weighted multivariable logistic regression, and subgroup analysis. In the Mendelian randomization (MR) analysis, the outcome was precisely defined as coronary heart disease (CHD), and the data primarily originated from the IEU OpenGWAS project. RESULTSA total of 10,158 participants aged 20-59 years were included, with a prevalence of cardiovascular diseases at 3.4%. Regional body fat was primarily associated with heart disease rather than with stroke. The RCS indicated a positive linear correlation between all body fat masses and the percentage of heart disease. After adjusting for confounding factors, logistic regression analysis revealed significant associations between heart disease and head fat mass (unit: 0.1 kg, odds ratio [OR] = 1.31, p = 0.002), head fat percentage (unit: 1%, OR = 1.37, p = 0.018), arm fat mass (unit: 1 kg, OR = 1.18, p = 0.047), and trunk fat mass (unit: 2.5 kg, OR = 1.14, p = 0.027). Leg fat mass and percentage of fat in the arms, trunk, and legs showed no significant correlation with heart disease (p > 0.05). The IEU OpenGWAS database does not include head-fat information. MR meta-analysis indicated that the fat mass and percentage in the arms, trunk, and legs were all causally related to CHD. CONCLUSIONHead fat mass, head fat percentage, arm fat mass, and trunk fat mass were all associated with heart disease and were likely causally related. WHAT IS KNOWNTrunk fat mass is positively associated with certain cardiovascular risk factors, while leg fat mass is the opposite. Dual-Energy X-ray Absorptiometry measures regional body fat, characterized by its speed, low radiation exposure, and cost-effectiveness, making it suitable for community settings. WHAT THE STUDY ADDSIn middle-aged and young adults, regional body fat mass and percentage are not associated with stroke. Head fat mass, head fat percentage, arm fat mass, and trunk fat mass are all associated with heart disease and are likely causally related. Measurement of fat in the head, arms, and trunk may contribute to early screening forheart diseases in middle-aged and young adults.