Objective: Grip strength and gait speed are objective measures of physical function, which in turn is an indicator of biological aging. We evaluate the association between age at natural menopause (ANM) and physical functioning in a sample of postmenopausal women drawn from the International Mobility in Aging Study (IMIAS).
Study design: Retrospective cohort study of 775 women aged 65-74, from Albania, Brazil, Colombia and Canada, who had experienced natural menopause.
Main outcome measures: Gait speed and grip strength were obtained following standardized protocols. The association between self-reported ANM (<40, 40-44, 45-49, 50-54 and ≥55) and gait speed (m/s) and grip strength (kg) was assessed by linear regression analyses adjusting for several life-course economic and reproductive exposures, height, BMI and smoking.
Results: Overall, women with ANM ≥ 55 had higher gait speed than those with ANM 50-54 (β = 0.05; 95%CI: 0.01, 0.10). Women with ANM < 40 had significantly lower grip strength compared with all other groups (β= -2.58; 95%CI: -4.43, -0.74). In region-specific analyses, ANM was associated with grip strength in Albania and Latin America and with gait speed in Albania only. No associations were observed in Canada.
Conclusions: ANM is associated with markers of physical functioning. Differences across study sites suggest that women in socially disadvantaged areas may reach menopause with different physiological reserves than those from more advantaged settings, leading to greater losses in muscle strength in postmenopausal years. More work comparing distinct populations is needed to better understand the underlying mechanisms.
Keywords: Frailty; Menopause; Muscle mass; Physical function; Sarcopenia.
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