Appendicular lean mass associated with bone mass in postmenopausal women

Among postmenopausal women living in Brazil, lower appendicular lean mass was independently associated with low bone mass, according to findings of a cross-sectional study published in Menopause.

“Menopause-related hormonal changes predispose women to bone loss, and the identification of risk factors in this population can help in the early diagnosis and preventive measures against low bone mass,” Tayane M. Fighera, MD, PhD, of the gynecological endocrinology unit at the Hospital de Clínicas de Porto Alegre in Rio Grande do Sul in Brazil, and colleagues wrote. “Previous data suggest that low muscle mass and, particularly, appendicular lean mass can be used as a predictor of postmenopausal osteoporosis considering the available sarcopenia cutoff points. However, using the same cutoff indicated for sarcopenia assessment may not be sufficient for the early identification of women at higher risk for low bone mass after menopause.”

Fighera and colleagues analyzed blood samples from 139 postmenopausal women aged 42 to 68 years without CVD who lived in southern Brazil. Women were excluded if they had used hormone therapy in the past 3 months, had diabetes or a previous or current diagnosis of heart disease or currently smoked.

Participants underwent physical examinations to assess body measurements and dual-energy X-ray absorptiometry to assess bone mineral density and body composition. Blood samples drawn in the morning after a 12-hour fast were used to assess serum sex hormone-binding globulin and follicle-stimulating hormone levels. The researchers also evaluated serum estradiol levels for 57 women who had provided a large enough serum sample to do this measurement.

Compared with normal bone mineral density, low bone mass was associated with longer time since menopause (mean, 3 vs. 5 years; P = .025), lower BMI (mean, 27.7 vs 25 kg/m²; P < .001), smaller waist circumference (mean, 93 vs. 84 cm; P < .001), lower estradiol levels (mean, 6 vs. 3 pg/mL; P = .006), lower fat mass index (mean, 11.38 vs. 9.36 kg/m²; P < .001), lower lean mass index (mean, 15.38 vs. 14.31 kg/m²; P = .003) and less appendicular lean mass (mean, 17.184 vs. 15.739 kg; P = .001).

In univariate models, free estrogen index, time since menopause, sex hormone-binding globulin, fat mass and appendicular lean mass were predictors of low bone mass. In multivariate models, significant associations remained for appendicular lean mass only, such that less appendicular lean mass predicted low bone mass.

“The results of the present study suggest that appendicular lean mass was a significant independent predictor against bone mass in postmenopausal women,” Fighera and colleagues wrote. “Further prospective studies are needed to investigate whether lean mass, fat mass and follicle-stimulating hormones have a direct effect on bone mass in postmenopausal women, adding to the consequences of hypoestrogenism in this group.”