Influence of weight and gonadal status on total and regional bone mineral content and on weight-bearing and non-weight-bearing bones, measured by dual-energy X-ray absosorptiometry

Abstract

Objective: To evaluate the influence of weight on total body bone mineral content (BMC TB) and regional body bone mineral content (head, arms, trunk and legs). This was studied in accordance with gonadal status and the weight-bearing or non-weight-bearing status of each region. Methods: The study included 94 postmenopausal women (mean age 60.6 ± 10.5 years), 36 perimenopausal women (mean age 49.0 ± 2.3 years) and 60 premenopausal women (mean age 36.1 ± 6.9 years). Full-body bone densitometry (DXA), for measuring total body bone and regional bone mineral content, was carried out in all the women. Results: Among these groups, the influence of 1 kg of body weight on total and regional bone mineral content (percent) did not differ (paired test P ns). In the overall group of women, paired comparison showed differences between the head and other zones measured ( P=0.036 – 0.004). In the overall group of women, no differences were found in the percent influence of 1 kg body weight on bone mineral content in any study zone (by ANOVA, Fisher's PLSD post hoc test and the Kruskal-Wallis test). In the overall group of women, Fisher's r to z test revealed a non-significant relationship between weight and the bone mineral content of the head ( r = 0.49, P ns) but in every other region the relationship between weight and the bone mineral content was significant ( r = 0.36 – 0.54, P < 0.0001 in all). Conclusions: The effect of body weight on BMC TB and regional did not differ significantly with either gonadal status or weight-bearing (legs) and non-weight-bearing bones (arms).