Influence of menopausal status on the main contributors of muscle quality

Muscle quality is a strong independent predictor of physical function. Body mass and fatness, muscle mass and cardiorespiratory fitness are known to influence muscle quality.

To identify the contributors of muscle quality in young and postmenopausal women and whether hormone replacement therapy (HT) could influence this relationship at the age of menopause.

Fifty-four postmenopausal women, 27 not on HT (PMW) and 27 on HT (PMW-HT), and 33 young women (YW) were evaluated for (1) body composition (body mass index, BMI), total fat mass (FM, %), appendicular lean mass (ALM, in kg and %), and appendicular skeletal mass index (ASMI = ALM/height² in kg/m²); (2) absolute peak oxygen uptake (VO_2peak, in ml/min) and relative peak oxygen uptake (VO_2peakRel in ml/kg/min); and (3) absolute isometric knee extension strength (iKES in kg) and relative isometric knee extension strength (iKES/BMI and iKES/ALM).

YW, PMW and PMW-HT had similar BMI (32.1 ± 10.2, 27.3 ± 4.7 and 26.7 ± 4 kg/m²) and FM (39.8 ± 10.0, 39.8 ± 7.3 and 39.9 ± 7.1%), respectively. Correlations were found between iKES/BMI index and FM (r = -0.52), ALM (r = 0.32) and VO_2peak (r = 0.31). Regression analysis demonstrated that, in YW, total amount of variance in iKES/BMI was mostly explained by ALM (42%), whereas, in PMW and PMW-HT, it was cumulatively explained by FM along with VO_2peakRel (34 and 46%, respectively).

The main contributors of muscle quality differ between young and postmenopausal women and HT does not seem to influence this relationship.