Abstract Body (Do not enter title and authors here): Background
Among older adults whose body mass index (BMI) readings may be spuriously reduced due to loss of skeletal muscle, BMI alone may lack specificity for body fat quantitation. In addition, sex-based hormones differentially influence body fat composition between the sexes with aging. To evaluate the cardiometabolic effect of body fat on older adults, we hypothesize that sex would exert differential effects on baseline and progression of cardiac dysfunction in older adults.

Methods
Community older adults without cardiovascular disease (CVD) underwent prospective transthoracic echocardiography with simultaneous body fat quantitation (body fat mass (BFM), percentage body fat (PBF), and waist-hip ratio (WHR) by bioimpedance, at baseline and five-year intervals. Mitral early diastolic inflow velocity to early diastolic annular tissue velocity (E/e') and early to late diastolic inflow velocity (E/A) ratios were recorded. Multivariable regression models were adjusted for significant clinical variables. Adverse clinical outcomes were defined as mortality or hospitalization during follow-up.

Results
Baseline and interval annotation of 409 older adults (mean age 61±12.7 years, 52% females) demonstrated deteriorations in E/A ratios of -0.1 ± 0.3 and E/e' ratios of 1.8 ± 2.8, over a mean duration of 4.9 ± 0.4 years. Baseline BFM (β -0.01, p<0.001; β 0.023, p=0.352) and PBF (β -0.008, p=0.002; β -0.007, p=0.759) predicted interval changes in E/A but not E/e' respectively independent of covariates (Table 1). In sex-specific analyses, higher baseline PBF was associated with deteriorations in E/A (β 0.010, p=0.028) among women and E/e' among men (β -0.069, p=0.020). Increases in PBF over time were particularly associated with reductions in E/A among women (β -0.005, p=0.047) independent of higher baseline PBF, in addition to significant interactions between sex and PBF in predicting changes in E/A. (Figure 1). Higher baseline WHR predicted adverse clinical outcomes [w1] among women (HR 1.09, 95%CI 1.03-1.16, p=0.005).

Conclusion
Baseline and longitudinal increases in fat quantity defined a trajectory of deteriorations in cardiac function among older adults, and prognosticated poorer future outcomes, particularly among women with central adiposity as represented by WHR. Refining CVD risk based upon quantitative sex-specific fat targets for older adults may be a strategy in the future.