Elgán Carina, Fridlund Bengt
Department of Health Sciences, Division of Nursing, Lund University, P.O. Box 157, S-221 00 Lund, Sweden.
Int J Nurs Stud. 2006 Aug;43(6):663-72. doi: 10.1016/j.ijnurstu.2005.10.009. Epub 2005 Dec 15.
To identify important predictors among lifestyle behaviours and physiological factors of bone mineral density (BMD) in relation to body mass index (BMI) among young women over a 2-year period. DESIGN, SAMPLE AND MEASUREMENTS: Data were collected in 1999 and 2001. Healthy young women (n=152) completed a questionnaire. BMD measurements were performed by DEXA in the calcaneus. The women were subdivided into three categories according to baseline BMI.
Baseline bodyweight explained 25% of the variability in BMD at follow-up in the BMI<19 category, and high physical activity seemed to hinder BMD development. In the BMI>24 category, a difference in time spent outdoors during winter between baseline and follow-up was the single most important factor for BMD levels. Overweight women with periods of amenorrhoea had lower BMD than overweight women without such periods.
Predictors and lifestyle behaviours associated with BMD are likely to be based on women of normal weight. BMI should be considered when advising on physical activity, since high physical activity seems to impair BMD development among underweight young women, possibly due to energy imbalance. Among overweight women, sleep satisfaction is the greatest predictor associated with BMD change and may indicate better bone formation conditions. Energy balance and sleep quality may be prerequisites of bone health and should be considered in prevention.
确定在两年时间里，年轻女性中与体重指数（BMI）相关的生活方式行为和骨矿物质密度（BMD）生理因素中的重要预测指标。设计、样本与测量：数据于1999年和2001年收集。健康年轻女性（n = 152）完成了一份问卷。采用双能X线吸收法（DEXA）测量跟骨的骨密度。根据基线BMI将这些女性分为三类。
在BMI<19的类别中，基线体重解释了随访时骨密度变异性的25%，且高体力活动似乎会阻碍骨密度的发展。在BMI>24的类别中，基线和随访期间冬季户外活动时间的差异是骨密度水平的唯一最重要因素。有闭经期的超重女性的骨密度低于无此时期的超重女性。
与骨密度相关的预测指标和生活方式行为可能基于体重正常的女性。在就体力活动提供建议时应考虑BMI，因为高体力活动似乎会损害体重过轻的年轻女性的骨密度发展，这可能是由于能量失衡所致。在超重女性中，睡眠满意度是与骨密度变化相关的最大预测指标，可能表明更好的骨形成条件。能量平衡和睡眠质量可能是骨骼健康的先决条件，在预防中应予以考虑。
