WHAT IN THE HEALTH IS GOING ON IN PERIMENOPAUSE: AN EVALUATION OF MUSCLE CHARACTERISTICS AND SYMPTOMOLOGY

This study examined muscle size (MS) and quality (MQ) in 21 perimenopausal (PERI) women with HIGH (n=11; ≥0.027 ng/mL) and LOW (n=10; <0.072 ng/mL) estrogen-to-progesterone (E:P) ratios, using advanced imaging methods of muscle assessment, and explored the relationship between muscle health, body composition, physical activity (PA), mood, and symptom severity. The findings revealed significant correlations (p<0.001) between the different muscle assessment techniques. Compared to the HIGH E:P group, the LOW E:P group showed lower muscle area (mean difference±standard error; MD±SE: 1049.7±593.0 mm²) and fat-muscle density (MD±SE: 5.7±3.4 mg/cm³, p=0.055), along with higher bone-to-muscle area (MD±SE: -0.4 ±0.1%, p=0.002) and fat-to-muscle area ratios (MD±SE: -35.2±18.9%, p=0.040). In the HIGH E:P group, walking activity, MQ (echo intensity), and body weight were significant predictors of symptom severity. These results suggest that hormonal profiles impact muscle size, quality, and symptom burden during PERI, underscoring the need for multi-modal muscle assessments across the transition.