Surgical menopause and frailty risk in older community dwelling women: the study of osteoporotic fractures
BACKGROUND: Low testosterone levels in older women have been shown to be associated with frailty. Whether older postmenopausal women with a history of bilateral oophorectomy before natural menopause resulting in lower testosterone levels (surgical menopause) have higher risk for frailty is not known. This prospective study investigated whether women who had surgically-induced menopause had a greater risk of frailty than naturally menopausal women. Furthermore, we also determined whether lower serum testosterone levels would be associated with frailty in our study population of older postmenopausal women. METHODS: The sample included 7699 community-dwelling white women aged ≥ 65 years from the Study of Osteoporotic Fractures (SOF). Participants were determined to have undergone surgical versus natural menopause based on whether or not they reported retrospectively having undergone a bilateral oophorectomy before or after menopause. Frailty status was classified as not frail, somewhat frail (hereafter referred to as Intermediate stage), frail or death at four interviews, conducted 6-18 years post-baseline. Baseline serum total testosterone concentrations were available on a subset of 541 participants. RESULTS: Approximately 12.6% of the participants reported surgical menopause. A total of 39.7% were classified as somewhat frail (intermediate stage) and 10.1% as frail. Twenty-two (22.0%) of the participants died during the interview period when frailty was assessed. Mean age at baseline was 71.2 years. Total serum testosterone levels were significantly lower among surgically menopausal women compared to naturally menopausal women (p<0.01). Surgical menopause was not significantly associated with an increased risk of frailty (Odds Ratio=0.94; 95% CI=0.72-1.22), intermediate stage frailty (Odds Ratio=0.96; 95% CI=0.80-1.10) or death (Odds Ratio=1.17 ; 95% CI=0.97-1.42) after adjusting for age, BMI and number of IADL impairments. Stratified analyses showed that oral estrogen use did not modify these associations. CONCLUSION: Among postmenopausal women, surgical menopause was not associated with a higher risk for frailty compared to naturally menopausal women, even in the absence of estrogen therapy. Future prospective studies are needed to investigate hormonal mechanisms involved in the development of frailty in older postmenopausal women.