Exploring the Relationships between Sex Hormones and Abdominal Muscle Area and Radiodensity in Postmenopausal Women: Insights from the Multi-Ethnic Study of Atherosclerosis

Abstract

The relationships between sex hormone levels and muscle composition in postmenopausal women remain underexplored. To address this gap, we conducted a cross-sectional observational study utilizing data from the Multi-Ethnic Study of Atherosclerosis. Our analysis included 682 postmenopausal women aged 45–84 years with complete data, with a mean age of 63.3 years. Using abdominal computed tomography, we assessed abdominal muscle area (cm²) and muscle radiodensity (Hounsfield units) in relation to serum levels of testosterone (total and free), estradiol, and sex hormone binding globulin (SHBG), measured in nmol/L.

Multivariable linear regression models, adjusting for potential confounders, were employed to investigate these associations. In our fully adjusted models, higher levels of estradiol and free testosterone were found to be positively associated with total area of abdominal muscle (β = 1.41, 95 % CI 0.4, 2.4, p = 0.007 and β = 18.5, 95 % CI 4.0, 33.1, p = 0.004, respectively), but not with muscle radiodensity (p > 0.05). Conversely, elevated levels of SHBG were associated with a smaller total of area abdominal muscle and radiodensity (β = −2.1, 95 % CI -3.2, −0.9, p = 0.001 and β = −0.32, 95 % CI -0.6, −0.0, p = 0.07, respectively).

Our study highlights significant associations between sex hormone levels and skeletal muscle area in postmenopausal women. Furthermore, the novel findings regarding SHBG and muscle composition suggest a potential previously unrecognized role of SHBG in the accumulation of skeletal muscle adipose tissue. However, further validation in other cohorts is necessary to elucidate the potential role of SHBG in body composition.

Clinical Trial: NCT00005487.