Peripheral Volumetric Bone Mineral Density in Pre- and Postmenopausal Chinese Women in Hong Kong

Abstract.

The aim of this cross-sectional study was to use a newly available precise and multislice pQCT (Densiscan 2000) for establishing reference data of volumetric bone mineral density (vBMD) of the distal radius. vBMD of the nondominant wrist was measured in 118 healthy Hong Kong Chinese women aged 41–60. Anthropometric parameters, menstrual status, and handgrip strength were also measured. Results showed that there was a significant age-related decline in trabecular BMD (tBMD), integral BMD (iBMD), and cortical BMD (cBMD), with correlation coefficients ranging from −0.401 to −0.547 (P < 0.001). The annual decline of vBMD was 2.22%, 1.79%, and 0.88% in tBMD, iBMD, and cBMD, respectively. When subjects were divided into premenopausal and postmenopausal groups, we found an age-related decline in tBMD and iBMD, but not in cBMD in both groups. The vBMD values interpreted in mg/cm³ in premenopausal women were 238.4 ± 57.2 in tBMD, 604.6 ± 82.9 in iBMD, 1415.5 ± 129.9 in cBMD, and declined significantly (all P < 0.001) to 193.7 ± 54.7 in tBMD, 500.0 ± 90.3 in iBMD, and 1306.7 ± 153.5 in cBMD in the postmenopausal women. On average, 16.7% of the subjects showed their vBMDs to be below −1 SD and only 1.7% of them lower than −2 SD. Linear regression showed that the annual decline of vBMD was faster in postmenopausal women with 2.42% in tBMD, 1.90% in iBMD, and 0.88% in cBMD compared with 1.91% in tBMD, 0.98% in iBMD, and 0.55% in cBMD in the premenopausal women. After adjustment for age, only the iBMD with dominant trabecular elements showed a significantly accelerated decrease after the onset of menopause (P= 0.008). Weak or no association was found among vBMDs with anthropometric parameters, years since menopause, or handgrip strength. In conclusion, we found a significant age-related decline of vBMDs in Hong Kong Chinese women aged 41–60 years, characterized by the early reduction of metabolically active trabecular bone after entering the fourth decade of life, with an accelerated decline after the onset of menopause.