Aires Nibia, Selmer Randi, Thelle Dag
The Cardiovascular Institute, Department of Medicine, Sahlgrenska University Hospital/Ostra, Gothenburg, Sweden.
Eur J Epidemiol. 2003;18(6):479-85. doi: 10.1023/a:1024682523710.
The importance of leisure time physical activity as a health indicator became more obvious after the results of large prospective studies were published. The validity of these results depends upon both the selection of the active individuals and to what extent self-reported physical activity reflects the individual's true activity. The purpose of this paper is to describe the changes in self-reported physical activity, and to assess the relation between this variable and other biological risk factors such as blood lipids, blood pressure and body mass index (BMI). This report also aims at corroborating the validity of self-reported physical activity by assessing the consistency of the associations between these biological risk factors and physical activity during a 25-years period. The basis for this analysis is a long lasting observational study with a questionnaire as the most important research instrument, in addition to physiological and biological factors such as BMI, blood pressure and blood lipids. The study population consists of 332,182 individuals, aged 40-42 from different counties in Norway who were invited to participate in health survey during 1974-1999. The objectives of this study are (1) to describe changes in self-reported physical activity from 1974 to 1999; (2) to assess the relation between physical activity and the biological variables; and (3) to corroborate the validity of the variable physical activity by assessing the consistency of the above analysis. The results of the analyses of association between decade of birth and self-reported physical activity show that physical activity among 40-aged individuals decreased during 1974-1999. This trend is stronger among the men. Multivariate analyses revealed differences in BMI and serum cholesterol between levels of self-reported physical activity, gender, smoking habits and decade of birth. The explained percentage of the total variance ranged from 6% for BMI to 7% for serum cholesterol. The similar shape of serum cholesterol and BMI according to physical activity indicates that the validity of self-reported physical activity has remained stable over these 25 years. Furthermore, the analysis of covariance showed that the slopes relating year of birth and serum cholesterol and BMI are parallel for self-reported physical activity thus the validity of the variable is confirmed.
大型前瞻性研究结果发表后，休闲时间体力活动作为健康指标的重要性变得更加明显。这些结果的有效性既取决于活跃个体的选择，也取决于自我报告的体力活动在多大程度上反映了个体的真实活动。本文的目的是描述自我报告的体力活动的变化，并评估该变量与其他生物危险因素（如血脂、血压和体重指数（BMI））之间的关系。本报告还旨在通过评估25年期间这些生物危险因素与体力活动之间关联的一致性，来证实自我报告的体力活动的有效性。该分析的基础是一项长期观察性研究，除了BMI、血压和血脂等生理和生物因素外，问卷是最重要的研究工具。研究人群包括来自挪威不同县的332182名40 - 42岁的个体，他们在1974年至1999年期间被邀请参加健康调查。本研究的目标是：（1）描述1974年至1999年自我报告的体力活动的变化；（2）评估体力活动与生物变量之间的关系；（3）通过评估上述分析的一致性来证实变量体力活动的有效性。出生年代与自我报告的体力活动之间关联分析结果表明，40岁个体的体力活动在1974年至1999年期间有所下降。这种趋势在男性中更为明显。多变量分析显示，自我报告的体力活动水平、性别、吸烟习惯和出生年代之间在BMI和血清胆固醇方面存在差异。总方差的解释百分比范围从BMI的6%到血清胆固醇的7%。血清胆固醇和BMI根据体力活动呈现出相似的形状，这表明自我报告的体力活动的有效性在这25年中保持稳定。此外，协方差分析表明，出生年份与血清胆固醇和BMI之间的斜率对于自我报告的体力活动是平行的，因此该变量的有效性得到了证实。
