Dwyer T, Hosmer D, Hosmer T, Venn A J, Blizzard C L, Granger R H, Cochrane J A, Blair S N, Shaw J E, Zimmet P Z, Dunstan D
Murdoch Childrens Research Institute, Royal Children's Hospital, Parkville, Melbourne, Victoria, Australia.
Int J Obes (Lond). 2007 May;31(5):797-804. doi: 10.1038/sj.ijo.0803472. Epub 2006 Oct 17.
Physical activity (PA) is inversely associated with obesity but the effect has been difficult to quantify using questionnaires. In particular, the shape of the association has not yet been well described. Pedometers provide an opportunity to better characterize the association.
Residents of households over the age of 25 years in randomly selected census districts in Tasmania were eligible to participate in the AusDiab cross-sectional survey conducted in 1999-2000. 1848 completed the AusDiab survey and 1126 of these (609 women and 517 men) wore a pedometer for 2-weekdays. Questionnaire data on recent PA, TV time and other factors were obtained. The outcomes were waist circumference (in cm) and body mass index (BMI) (kg/m(2)).
Increasing daily steps were associated with a decline in the obesity measures. The logarithmic nature of the associations was indicated by a sharper decline for those with lower daily steps. For example, an additional 2000 steps for those taking only 2000 steps per day was associated with a reduction of 2.8 (95% confidence interval (CI): 2.1,4.4) cm in waist circumference among men (for women; 2.2 (95% CI: 0.6, 3.9 cm)) with a baseline of only 2000, steps compared to a 0.7 (95% CI 0.3, 1.1) cm reduction (for women; 0.6 (95% CI: 0.2, 1.0)) for those already walking 10,000 steps daily. In the multivariable analysis, clearer associations were detected for PA and these obesity measures using daily step number rather than PA time by questionnaire.
Pedometer measures of activity indicate that the inverse association between recent PA and obesity is logarithmic in form with the greatest impact for a given arithmetic step number increase seen at lower levels of baseline activity. The findings from this study need to be examined in prospective settings.
身体活动（PA）与肥胖呈负相关，但使用问卷调查难以量化这种影响。特别是，这种关联的形式尚未得到很好的描述。计步器为更好地描述这种关联提供了契机。
在塔斯马尼亚随机选择的普查区中，25岁以上家庭的居民有资格参加1999 - 2000年进行的澳大利亚糖尿病横断面调查。1848人完成了澳大利亚糖尿病调查，其中1126人（609名女性和517名男性）在两个工作日佩戴计步器。获取了关于近期身体活动、看电视时间和其他因素的问卷数据。结果指标为腰围（厘米）和体重指数（BMI）（千克/平方米）。
每日步数增加与肥胖指标下降相关。对于每日步数较少者，关联呈现对数性质，下降更为明显。例如，对于每天仅走2000步的男性，每天额外增加2000步与腰围减少2.8（95%置信区间（CI）：2.1, 4.4）厘米相关（女性为2.2（95%CI：0.6, 3.9厘米）），而对于每天已经走10000步的人，腰围减少0.7（95%CI 0.3, 1.1）厘米（女性为0.6（95%CI：0.2, 1.0））。在多变量分析中，使用每日步数而非问卷中的身体活动时间，能更清晰地检测到身体活动与这些肥胖指标之间的关联。
计步器测量的活动表明，近期身体活动与肥胖之间的负相关呈对数形式，在较低基线活动水平下，给定算术步数增加产生的影响最大。本研究结果需要在前瞻性研究中进行检验。
