Zhu K, Hunter M, James A, Lim E M, Cooke B R, Walsh J P
Department of Endocrinology and Diabetes, Sir Charles Gairdner Hospital, Nedlands, WA, 6009, Australia.
School of Medicine and Pharmacology, University of Western Australia, Crawley, WA, Australia.
Osteoporos Int. 2017 Jan;28(1):259-268. doi: 10.1007/s00198-016-3710-8. Epub 2016 Jul 29.
The obesity-BMD relationship is complex. In 3045 middle-aged adults, we found that in women (but not men) with discordant fat mass index (FMI)/BMI categories, higher body fat for BMI was associated with lower BMD, suggesting that increased fat mass without an accompanying increase in lean mass may be deleterious to bone.
The relationship between obesity and BMD is complex. FMI (fat mass (kg) / height (m)) is a more accurate measure of fatness than BMI, and depending on body composition, some individuals have discordant BMI/FMI categories. We examined associations between FMI, BMI and BMD in participants in the Busselton Healthy Ageing Study.
Body composition and BMD of the hip, spine and total body were measured using DXA in 3045 participants (1644 females) aged 45-67 years. Using standard BMI/FMI categories, the participants were classified as underweight/fat deficit, normal, overweight/excess fat, obese I and obese II-III.
BMI and FMI categories were concordant in 77.3 % of females and 71.2 % of males. There were 12.9 % females and 13.2 % males in a higher FMI than BMI category (high body fat for BMI), whereas 9.8 % females and 15.6 % males were in a lower category (low body fat for BMI). Females with high body fat for BMI had significantly lower covariate-adjusted BMD at the femoral neck, total hip and total body (differences of 3.8, 5.1 and 2.6 %, respectively, all P < 0.05) than females with low body fat for BMI and lower total body BMD than women with concordant FMI/BMI (by 1.4 %, P = 0.04). In males, BMD did not differ significantly between those who were concordant or discordant for FMI/BMI categories.
In women (but not men) with discordant FMI/BMI categories, higher body fat for BMI was associated with lower BMD, suggesting that increased fat mass without an accompanying increase in lean mass may be deleterious to bone.
肥胖与骨密度的关系很复杂。在3045名中年成年人中，我们发现，在脂肪质量指数（FMI）/体重指数（BMI）类别不一致的女性（而非男性）中，相对于BMI而言更高的体脂与更低的骨密度相关，这表明脂肪量增加而瘦体重未随之增加可能对骨骼有害。
肥胖与骨密度的关系很复杂。FMI（脂肪量（千克）/身高（米））是比BMI更准确的肥胖衡量指标，并且根据身体组成情况，一些个体的BMI/FMI类别不一致。我们在巴瑟尔顿健康老龄化研究的参与者中研究了FMI、BMI与骨密度之间的关联。
使用双能X线吸收法（DXA）测量了3045名年龄在45至67岁的参与者（1644名女性）的身体组成以及髋部、脊柱和全身的骨密度。根据标准的BMI/FMI类别，将参与者分为体重过轻/脂肪不足、正常、超重/脂肪过多、I级肥胖和II - III级肥胖。
77.3%的女性和71.2%的男性的BMI和FMI类别一致。FMI高于BMI类别的女性占12.9%，男性占13.2%（相对于BMI而言体脂高），而FMI低于BMI类别的女性占9.8%，男性占15.6%（相对于BMI而言体脂低）。相对于BMI而言体脂高的女性在股骨颈、全髋和全身的协变量调整骨密度显著低于相对于BMI而言体脂低的女性（差异分别为3.8%、5.1%和2.6%，均P<0.05），并且全身骨密度低于FMI/BMI一致的女性（低1.4%，P = 0.04）。在男性中，FMI/BMI类别一致或不一致的人群之间骨密度无显著差异。
在FMI/BMI类别不一致的女性（而非男性）中，相对于BMI而言更高的体脂与更低的骨密度相关，这表明脂肪量增加而瘦体重未随之增加可能对骨骼有害。
