Abstract P289: Sex Differences in the Rate of Visceral Adipose Tissue Accrual During Adulthood

Abstract

Introduction: Excess visceral adipose tissue (VAT) robustly predicts incident cardiometabolic risk, independent of body mass index (BMI), and this association is stronger in women than in men. Cross-sectional studies suggest that VAT accrual accelerates in older women as compared to similarly aged men, in concert with menopausal changes, which may help to explain the greater effect of VAT on subsequent disease risk observed in women. However, a direct test of sex differences in the rate of VAT accrual requires longitudinal VAT data which have been largely lacking. Objectives: This analysis evaluated sex differences in the rate of VAT accrual in adults. Secondary analyses examined differences in the rate of VAT accrual in pre-, peri-, and post-menopausal women. Methods: Participants were 532 (59% female) non-Hispanic white adults, aged 18-84 years at baseline, who were enrolled in a study of normative changes in body composition over the lifespan. Abdominal VAT mass and subcutaneous adipose tissue (SAT) mass were assessed using multiple-image magnetic resonance imaging at two time points, with an average follow-up of 7.2 ± 2.5 years. Linear regression models were used to examine the effects of sex, baseline age, and their interaction on rate of change per year in body composition measures (ΔBMI, ΔVAT, and ΔVAT/SAT ratio (ΔVSR)) independent of baseline body composition measures and baseline visit year. Secondary analyses examined differences in these rates of change by baseline menopausal status (pre, peri, post), after adjustment for baseline age. Results: Levels of BMI, VAT, and VSR all increased over the follow-up period on average; however, the change in BMI (mean ΔBMI = +0.5%) was far smaller than for VAT (mean ΔVAT=+6.3%) and VSR (mean ΔVSR = +3.4%). ΔVAT and ΔBMI decreased linearly with age in both sexes (p<0.001), such that older individuals had lower rates of VAT and BMI gain, and this deceleration in VAT and BMI accrual was greater in men than women (p for interaction 0.007 and 0.038, respectively). ΔVSR did not vary with age in either sex, but remained higher in men than women throughout adulthood. ΔBMI, ΔVAT, and ΔVSR did not differ by baseline menopausal status. Conclusions: VAT mass increased with age in both men and women, but the rate of VAT gain gradually declined with advancing age. There was no evidence of accelerated VAT accrual during menopause as previously reported in the literature. However, the rate of VAT gain was more consistent in women during adulthood than in men, who exhibited greater deceleration. Future work will explore whether this sex difference in the pattern of body composition change explains the differential effects of VAT on disease risk in men and women.