健康成人体成分差异对不同年龄段人群骨密度的影响

Effect of Body Composition Diversity on Bone Mineral Density in Different Ages of Normal Adults

目的探讨健康成人体成分特点及对不同年龄段人群骨密度(BMD)影响的差异。方法693例成人根据性别及年龄进行分组,全身脂肪、瘦组织质量和全身、腰椎、股骨BMD采用双能X线骨密度仪(DEXA)检测。统计学处理应用Pearson相关分析和多元逐步回归分析等。结果男性脂肪百分比低于女性[(22.15±7.12)%vs(32.30±6.84)%,P<0.01],瘦组织百分比[(73.81±6.86)%vs(61.19±10.80)%,P<0.01]和骨矿盐百分比[(4.07±0.47)%vs(3.89±0.64)%,P<0.01]明显高于女性。男性<60岁全身、腰椎、股骨BMD与瘦组织质量、脂肪质量均呈显著正相关,≥60岁腰椎BMD与脂肪质量呈正相关,但瘦组织仍影响着BMD;女性随年龄增加,各部位BMD与瘦组织质量之间相关性减弱,与脂肪质量相关性增强。多元逐步回归分析证实瘦组织是影响男性和<50岁女性BMD变异的主要因素;在以绝经后女性为主的人群,<60岁女性体质量指数(BMI)或瘦组织仍影响着BMD变异,≥60岁女性脂肪则决定BMD变异。结论男性具有较多的瘦组织,是影响男性BMD变异的主要因素;女性具有较多的脂肪成分,但对BMD影响存在年龄上的差异,是决定≥60岁女性BMD变异的主要因素。

Objective To analyze the characteristics of body composition and to investigate the effect of body composition on bone mineral density（BMD）in healthy adults of different ages. Methods A sampling population of 693 was divided into different groups based on sex and age.Body fat,lean tissue mass and BMD of the whole body,lumbar spine and femur were measured with dual energy X-ray absorptiometry（DEXA）.The data were analyzed with Pearson correlations analysis and multiple stepwise regression analysis. Result It was observed that compared with women, men had lower body fat percentage [（22. 15±7. 12）% vs （32. 30±6. 84） %,P〈0.01], but much higher lean tissue percentage and bone mineral percentage [（73.81±6.86）% vs （61. 19±10.80）% and （4.07±0.47）% vs （3.89±0.64）%, respectively, P〈0.01]. BMD of the whole body, lumbar spine and femur in male groups under 60 years old proved to be positively correlated with lean tissue mass and fat mass, while in male groups of and over 60 years old, fat mass still showed a positive effect on BMD of lumbar spine, with lean tissue mass only affecting BMD. With the aging of females, the correlation between BMD and lean tissue mass decreased, while correlation between BMD and fat mass increased. Multiple stepwise regression analysis revealed that lean tissue mass was the main factor affecting BMD in females under 50 years old and males. In postmeno- pausal females, BMI and lean tissue mass of those under 60 years old still affected the variation of BMD, while in terms of those of and over 60 years old, fat mass was independently associated with the variation of BMD and had a good linear relationship. Conclusion The present data show that men have more lean mass, which is the main factor influencing the variation of BMD, while women have more fat mass, which exerts different influences on BMD in groups of different ages and serves as the determinant factor for the variation of BMD in those of and over 60 years old.