Akhtar-Danesh Noori, Dehghan Mahshid, Merchant Anwar T, Rainey James A
Open Med. 2008;2(3):e83-8. Epub 2008 Aug 26.
To examine the validity of self-reported body mass index (BMI) in estimating the prevalence of obesity in the Canadian population, and to suggest a model for predicting actual BMI from self-reported data.
This analysis is based on 1131 participants with both self-reported and measured height and weight from the Canadian Community Health Survey, Cycle 2.2 dataset. We estimated the prevalence of obesity as well as the mean and standard deviation (SD) of BMI according to sex, age group, and measured weight classification. Multiple regression analysis was used to build a model to assess the relation between actual BMI and variables of age, sex, and self-reported BMI.
The overall prevalence of obesity was 23.0% based on measured BMI, and 15.6% based on self-reported BMI. Estimated mean (SD) for self-reported and measured BMI were 25.8 (4.8) and 26.9 (5.0) kg/m(2), respectively. Only 74.3% of obese men and 56.2% of obese women were correctly classified as obese on the basis of self-reported measures. Females and heavier respondents showed more BMI under-reporting than others.
To estimate overweight and obesity in etiological and disease relationship studies, the use of measured height and weight in BMI estimation is preferable to the use of self-reported values. However, if self-reported height and weight are used in population studies, our proposed model can be used to reliably predict the actual BMI with a narrow 95% confidence interval.
检验自我报告的体重指数（BMI）在估计加拿大人群肥胖患病率方面的有效性，并提出一个根据自我报告数据预测实际BMI的模型。
本分析基于加拿大社区健康调查第2.2轮数据集中1131名参与者的自我报告身高和体重以及测量得到的身高和体重。我们根据性别、年龄组和测量体重分类来估计肥胖患病率以及BMI的均值和标准差（SD）。采用多元回归分析建立模型，以评估实际BMI与年龄、性别和自我报告BMI等变量之间的关系。
根据测量的BMI，肥胖的总体患病率为23.0%，而根据自我报告的BMI为15.6%。自我报告和测量的BMI的估计均值（SD）分别为25.8（4.8）和26.9（5.0）kg/m²。基于自我报告的测量，只有74.3%的肥胖男性和56.2%的肥胖女性被正确分类为肥胖。女性和体重较重的受访者比其他人表现出更多的BMI低报情况。
在病因学和疾病关系研究中估计超重和肥胖时，在BMI估计中使用测量的身高和体重比使用自我报告的值更可取。然而，如果在人群研究中使用自我报告的身高和体重，我们提出的模型可用于以较窄的95%置信区间可靠地预测实际BMI。
