Boreham C, Twisk J, Murray L, Savage M, Strain J J, Cran G
Sport and Exercise Science Sports Studies, Faculty of Business and Management, University of Ulster, United Kingdom.
Med Sci Sports Exerc. 2001 Feb;33(2):270-4. doi: 10.1097/00005768-200102000-00016.
The purpose of this study was to examine the independence and relative strengths of association between coronary heart disease (CHD) risk status and both body fatness and cardiorespiratory (C-R) fitness in 12- and 15-yr-old adolescents.
The study cohort consisted of 1015 schoolchildren aged 12 and 15 yr (251 12-yr-old boys, 258 12-yr-old girls, 252 15-yr-old boys, and 254 15-yr-old girls), representing a 2% random sample of each population group. For each child, height, weight, sexual maturity (pubertal status), skin-fold thicknesses (4 sites), blood pressure (random zero sphygmomanometer), nonfasting serum total, and high density lipoprotein (HDL)-cholesterol and C-R fitness (20-m shuttle run; 20-MST) were determined under standardized conditions. Socioeconomic status and habitual physical activity were also determined from questionnaire information. Multiple regression analyses were carried out to examine relationships between five CHD risk factors, and fitness and fatness and to examine the relative strengths of fitness and fatness on CHD risk status, correcting for potential confounding variables.
Our main findings were: 1) Relationships between fatness and CHD risk factors are invariably stronger than between fitness and the same risk factors. For example, partially adjusted standardized regression coefficients for 12-yr-old boys revealed significant relationships between all five CHD risk factors and fatness, compared with three of five for fitness. The corresponding figures for 12-yr-old girls were three of five (fatness) and one of five (fitness). Broadly similar results were apparent for 15-yr-olds. 2) Although relationships between fitness and CHD risk factors do not survive further adjustment for fatness, the relationships between fatness and CHD risk are more robust and are unaffected by further adjustment for fitness.
Our results indicate that the observed relationships between C-R fitness and CHD risk status in adolescents are mediated by fatness, whereas the observed relationships with fatness are independent of fitness. Primary prevention of CHD during childhood should therefore concentrate upon preventing or reversing undue weight gain.
本研究旨在探讨12岁和15岁青少年冠心病（CHD）风险状况与身体脂肪含量及心肺（C-R）适能之间的独立性及关联强度。
研究队列由1015名12岁和15岁的学童组成（251名12岁男孩、258名12岁女孩、252名15岁男孩和254名15岁女孩），占各人群组随机样本的2%。对每个孩子，在标准化条件下测定身高、体重、性成熟度（青春期状态）、皮褶厚度（4个部位）、血压（随机零点血压计）、非空腹血清总胆固醇和高密度脂蛋白（HDL）胆固醇以及C-R适能（20米穿梭跑；20-MST）。还通过问卷信息确定社会经济地位和习惯性身体活动。进行多元回归分析以检验五个CHD风险因素与适能和脂肪含量之间的关系，并在校正潜在混杂变量的情况下检验适能和脂肪含量对CHD风险状况的相对强度。
我们的主要发现是：1）脂肪含量与CHD风险因素之间的关系始终比适能与相同风险因素之间的关系更强。例如，12岁男孩部分调整后的标准化回归系数显示，所有五个CHD风险因素与脂肪含量之间均存在显著关系，而与适能相关的为五个中的三个。12岁女孩的相应数字为五个中的三个（脂肪含量）和五个中的一个（适能）。15岁青少年的结果大致相似。2）尽管适能与CHD风险因素之间的关系在进一步调整脂肪含量后不再显著，但脂肪含量与CHD风险之间的关系更稳健，且不受进一步调整适能的影响。
我们的结果表明，青少年中观察到的C-R适能与CHD风险状况之间的关系由脂肪含量介导，而观察到的与脂肪含量的关系独立于适能。因此，儿童期CHD的一级预防应集中于预防或逆转过度体重增加。
