Abstract Body: Introduction: Aging causes body fat redistribution, featured by an increase in ectopic adiposity. Gait speed, a key indicator of functional abilities, declines with aging. Persons of African ancestry have less visceral, hepatic, and pericardial, but more skeletal muscle adiposity compared to non-Hispanic Whites. They also have slower gait speed than non-Hispanic Whites. Several studies have reported an association between general or central obesity and gait speed; however, the results were inconsistent. Very few studies have assessed an association of multiple simultaneously-measured ectopic adiposity depots with gait speed.
Methods: We measured ectopic adiposity depots (visceral, hepatic, pericardial, and intermuscular (IMAT) in the abdomen, thigh, and calf) by computed tomography, and 4-meter usual gait speed in 775 community-dwelling men of African ancestry (mean age = 63.9 ± 8.6 years, mean body mass index (BMI) = 27.7 ± 4.6 kg/m²) in the Tobago Health Study. Anthropometrics were assessed using standard methods. Demographic, disease, and lifestyle characteristics were collected using a standardized questionnaire.
Results: Higher general adiposity, as measured by BMI, and visceral adiposity were associated with slower gait speed in basic models, but associations were attenuated after further adjustment (Table 1). Higher IMAT in all three muscle groups assessed (abdomen, thigh, and calf) was associated with slower gait speed even in fully adjusted models (Table 1). There was no association between hepatic nor pericardial adiposity and gait speed.
Conclusion: Ectopic adiposity, particularly within skeletal muscle, may play a key role in the loss of physical function in African Caribbeans. Longitudinal studies are needed to clarify the independent role of skeletal muscle adiposity in gait speed decline, and to identify possible local and systemic mechanisms underlying this association in high-risk persons of African ancestry.