膳食和体力活动因素对BMI影响的多水平分析研究

目的用多水平线性分析方法分析膳食和体力活动因素对BMI的影响。方法以"中国居民健康与营养调查"追踪调查项目中参加1997、2000和2004年三轮调查中至少一次调查的18～60岁成年人(男5565;女5833)为研究对象,拟合包括社区、个体和调查时间三个水平的多水平线性模型,分析平均每日总能量摄入量、脂肪供能比、中重度体力活动时间和其它社会经济因素对BMI的影响。结果调整了其它因素后,男性总能量摄入量与BMI呈正相关(β=0.000115,S-X=0.000188,P<0.01);女性中重度体力活动时间与BMI呈负相关(β=-0.00718,S-X=0.001839,P<0.001)。男性BMI在个体和社区水平的变异分别占51.8%和12.3%,女性分别为55.9%和7.9%。结论考虑了数据在社区、个体、调查时间的层次结构后,膳食和体力活动因素对BMI有影响,并且BMI的影响因素在不同性别间存在差异。

THE MULTILEVEL ANALYSIS OF THE EFFECT OF DIET AND PHYSICAL ACTIVITY FACTORS ON BMI

Objective To study the effect of diet and physical activity factors on BMI using the multilevel linear analysis method. Method The data were collected in the China Health and Nutrition Survey (CHNS). A total of 5 565 men and 5 833 women aged 18-60 were selected as the subjects who attended at least one of the surveys in the year of 1997,2000 and 2004. Three-level random intercept linear models including the levels of community,person and survey time were applied to estimate the relationship between the daily total energy intake,the percentage of total energy intake from fat,the time spent on the moderate or heavy physical activity,other socioeconomic factors and BMI. Results After adjusting other factors the total energy intake was positively associated with BMI(β=0.000115,S -X =0.000188,P<0.01)in men. The time spent on the moderate or heavy physical activity was negatively associated with BMI(β= -0.00718,S -X =0.001839,P<0.001)in women. An interaction existed between the time spent on the moderate or heavy physical activity and the residence area in women with the urban community having higher BMI than the rural community under the same physical activity level (β=0.0098,S -X =0.0043,P<0.05). Variances of the time,person and community level accounted for 35%-40%,50%,and 10%-15% of the total variance of BMI respectively. Conclusion After considering the three levels structure of the data,diet and physical activity are the factors influencing BMI and they are different between genders.