Black and White postmenopausal women have similar rates of peripheral bone density loss and microarchitecture deterioration after accounting for clinical covariates, according to a study published in the Journal of Bone and Mineral Research.
A total of 80 Black women (mean aged, 59.8±2.5 years) and 137 White women (mean aged, 60.0±2.8 years) from the Study of Women’s Health Across the Nation (SWAN) were included. SWAN initially enrolled 3302 premenopausal women not taking hormonal therapies from 1996 to 1997.
The researchers used high resolution peripheral quantitative computed tomography (HR-pQCT) to measure longitudinal changes in peripheral volumetric bone mineral density (vBMD), microarchitecture, and strength at the distal radius and tibia, with an average time from baseline to follow-up scans of 6.7±0.8 years. Among all women, the rates of decline in total and trabecular vBMD were 1.8- and 6-fold higher, respectively, at the radius than tibia (P < .0001 for both).
Unadjusted rates of bone decline tended to be greater at the radius in White women than in Black women. The average percentage loss in total bone mineral density (BMD) was about 23% greater in White versus Black women (P = .07). Similar patterns were found regarding the rate of decline in cortical bone volume and cortical BMD, which were 29% (P = .056) and 26% (P = .12) greater, respectively, in White women compared with Black women. The effect of race on rates of bone density and microarchitecture deterioration was attenuated for most outcomes after accounting for clinical covariates.
Age-related changes in density, microarchitecture, and strength at the tibia were mostly similar among Black and White women (all P > .26).
In the overall cohort, baseline weight was significantly associated with rates of bone loss in total BMD and trabecular BMD at the radius, with women in the lowest weight tertile having the greatest loss, even after adjustment for race and other covariates.
Women who lost >3% of their body weight during follow-up had the highest rates of bone density and microstructure decline. Those who gained weight during the follow-up maintained their tibial cortical bone microarchitecture, and those who lost weight during the follow-up had significant decreases in cortical bone volume (P = .008).
Among several study limitations, the investigators did not assess the role of several body composition variables such as visceral adipose tissue, and the study may have been insufficiently powered to detect small differences in rates of bone microstructure deterioration between Black and White women. In addition, because SWAN participants were initially recruited about 25 years ago, there is now potential for survivor bias and the rates of bone deterioration may be even greater in less-healthy, less-motivated postmenopausal women.
“Our findings reinforce the notion that it is important for postmenopausal women to maintain weight after menopause to avoid experiencing rapid bone loss and subsequent fractures,” the study authors wrote. “Additionally, older women who lose weight to achieve better health may need targeted interventions to prevent excessive bone loss caused by weight loss.”
Johannesdottir F, Putman MS, Burnett-Bowie S-AM, Finkelstein JS, Yu EW, Bouxsein ML. Age-related changes in bone density, microarchitecture, and strength in postmenopausal black and white women: The SWAN Longitudinal HR-pQCT Study. J Bone Miner Res. Published online October 14, 2021. doi: 10.1002/jbmr.4460