Abstract MP71: Novel Association Between Parity and Skeletal Muscle Adiposity in Middle-Aged and Older African Caribbean Women

Objective: Pregnancy and parity (number of children born to a women) are associated with alterations in metabolism and lifestyle, which may affect women’s short- and long-term cardiometabolic health. Greater skeletal muscle adiposity (myosteatosis) is recognized as a major risk factor for cardiometabolic diseases, especially in African ancestry individuals. While lifetime parity has been previously associated with greater central obesity years after childbearing ceased, it remains unclear whether parity is associated with myosteatosis. Methods: We examined the association of parity (0, 1, 2, 3, 4+) with myosteatosis and general and central obesity among 1,119 African Caribbean women, aged 40-84 years, recruited from 2019 to 2023 without regard to health status. Calf myosteatosis area was measured by CT-derived intermuscular adipose tissue (IMAT, mm 2 ) and skeletal muscle density (mg/cm 3 , with a lower density indicating more adiposity). Multivariable linear regression models were used to estimate the adjusted means of IMAT, muscle density, BMI, and waist circumference for each parity group. Results: The mean age of women who reported ever being pregnant (N=969) was 55.8 (SD=9.0) years. They were obese on average (BMI=32.1 (SD=6.8) kg/m 2 ), and had given birth to an average of 3 (SD=2.3) children. In multivariable models, higher parity was significantly associated with higher IMAT and lower muscle density, after accounting for age, BMI, physical activity, and comorbidities (see Table). Parity showed no associations with BMI or waist circumference. Conclusions: Parity may be associated with greater accumulation of adiposity in skeletal muscle, despite no link with general or central adiposity among African Caribbean women. Our novel findings, if confirmed in prospective studies, might highlight the need for tailored strategies for maintaining healthy muscles in multiparous women of African ancestry. Table. Adjusted population marginal means (95% CI) for myosteatosis by parity groups in African Caribbean women a