Endocrine Abstracts

Introduction: Low concentration of serum 25-hydroxyvitamin D (25-OHvitD) have been associated with low bone loss and risk of falls in postmenopausal women. Moderate obesity is not a risk factor for osteoporosis.

Aim: The aim of this study was to investigate how vitamin D concentration correlates with muscle strength and bone density in moderately obese postmenopausal women.

Methods: We include 33 postmenopausal women, between 50 and 60 years of age, coming for the first measure of dual-energy X-ray absorptiometry (DXA). The assessed parameters were: BMI, waist circumference (WC), 25-OHvitD, bone mineral density (BMD) measured by DXA and muscle strength. Muscle strength was measured as hand grip strength (HGS) with JAMAR Hand Dynamometer. Three measures on the right or left hand were averaged to get the absolute HGS and compared to the normative data for this aged group (47.3–57.3 pounds). T-test for continuous variables and Spearman test for correlations between variables were used.

Results: The postmenopausal women were 56.4±2.8 years old, menopausal duration 6.5±2.7 years, with BMI 28.01±3.4 kg/m² and WC 89.0±8.1 cm. The mean level of 25-OHvitD was 32.5±13.9 nmol/l. A significant negative correlation was observed between 25-OHvitD levels and both WC (ρ_wc=−0.65; P<0.001) and BMI (ρ_bmi=−0.49; P<0.003). The average HGS of these moderately obese participants was 28.3±4.2 pounds. It was significantly lower than the normative grip strength for referent range group (t=−21.65; P<0.001). A significant positive correlation was observed between 25-OHvitD levels and HGS (ρ_hgs=0.45; P<0.009). Average BMD on lumbar spine was 0.862 and 0.668 g/cm² on total hip. There was a very weak correlation between serum 25-OHvitD and BMD at lumbar spine (ρ=0.167; P=0.35) and hip (ρ=0.228; P=0.20).

Conclusion: Decreased levels of 25-OHvitD in moderately obese postmenopausal women are associated with low muscular strength. Decreased muscular strength may increase the risk of falls and fracture in moderately obese postmenopausal women.