Bone mineral density by ultrasonic measurement in pre- and postmenopausal women--relationship with sex hormones and nutritional states

Abstract

In this cross-sectional study we evaluated the relationships of the sex hormones, estradiol (E2), free testosterone (free T), dehydroepiandrosterone-sulfate (DHEA-S), sex hormone-binding globulin (SHBG) and nutritional status to bone density assessed by ultrasonic measurements. The subjects were 16 premenopausal (38-50 years) and 28 postmenopausal (47-86 years) women living in a rural area in Yamaguchi Prefecture in Japan. They were healthy and did not smoke or drink. Speed of sound (SOS), broadband ultrasound attenuation (BUA) and the stiffness index (SI) were used as the indices to evaluate ultrasonic bone density (UBD) for the calcaneus. In premenopausal women, the concentration of free T was negatively associated with BUA. The DHEA-S concentration had a significant negative correlation with BUA after adjustments for age and body mass index (BMI). Daily intakes of fat, animal fat, animal protein, calcium (Ca) and vitamin B2 (Vit B2) were positively associated with UBD. In postmenopausal women, although DHEA-S positively correlated with SOS, BUA and SI, the significance disappeared after adjustments for age and BMI. The protein intake was positively associated with BUA. Multiple regression analysis for SOS, BUA and SI as dependent variables was performed. Independent variables were age, BMI, E2, free T, DHEA-S, SHBG and daily intakes of animal fat, animal protein, Vit B2 and Ca. In premenopausal women, the animal fat intake contributed significantly and positively to the variations of SOS and SI. The intake of Vit B2 had a significant positive correlation, and the level of DHEA-S had a significant negative correlation with BUA. In postmenopausal women, age and BMI contributed significantly to the variations of SOS, BUA and SI, while the nutritional variables and the sex hormones were not found to be significant. In conclusion, different factors predicting UBD were suggested for pre- and postmenopausal women. In premenopausal women, daily intakes of animal fat and Vit B2 might be effective to maintain higher bone density. Further investigations are still needed to clarify the relationship between DHEA-S and UBD.