Department of Nutrition, Harvard School of Public Health, Boston, MA; Department of Epidemiology, Harvard School of Public Health, Boston, MA.
Int J Cancer. 2014 Aug 1;135(3):682-94. doi: 10.1002/ijc.28687. Epub 2014 Mar 3.
Although considerable evidence suggests that leisure-time physical activity is associated with a reduced risk of endometrial cancer (EC), the shape of dose-response relationship has not been investigated and previous meta-analyses have not accounted for differences in measures of physical activity. To address such issues, we conducted linear and nonlinear dose-response meta-analyses by metabolic equivalent of task (MET)-hour/week and hour/week, respectively, based on observational studies published up to September 2013 identified from PubMed and Embase databases. Summary relative risks (RRs) and 95% confidence intervals (CIs) were calculated using a random-effects model. In the linear dose-response analysis, an increase in leisure-time physical activity by 3 MET-hour/week was associated with an ∼2% reduced risk of EC (summary RR = 0.98, p = 0.02, 95% CI = 0.95-1.00, I(2) = 53%, p(heterogeneity) = 0.06, three case-control studies and three cohort studies, 3,460 cases, range of activity = 0-50 MET-hour/week) and an increase by an hour/week was associated with an ∼5% reduced risk of EC (summary RR = 0.95, p < 0.001, 95% CI = 0.93-0.98, I(2) = 31%, p(heterogeneity) = 0.20, four case-control studies and two cohort studies, 3,314 cases, range of activity = 0-12 hour/week). Nonlinear dose-response meta-analysis suggested that the curve may plateau at 10 MET-hour/week (p(change) in slope = 0.04) but this statistical significance was sensitive to one study. No evidence of a nonlinear association was indicated by hour/week (p(change) in slope > 0.69). In conclusion, an increase in leisure-time physical activity may continue to decrease EC risk, within the range of 0-50 MET-hour/week or 0-15 hour/week. Future studies should evaluate possible independent role of intensity of physical activity and effect modification by obesity.
尽管有大量证据表明，闲暇时间的体育活动与子宫内膜癌（EC）风险降低有关，但剂量反应关系的形状尚未得到研究，以前的荟萃分析也没有考虑到体育活动测量方法的差异。为了解决这些问题，我们根据截至 2013 年 9 月从 PubMed 和 Embase 数据库中检索到的观察性研究，分别以代谢当量（MET）-小时/周和小时/周为单位，进行了线性和非线性剂量反应荟萃分析。使用随机效应模型计算汇总相对风险（RR）和 95%置信区间（CI）。在线性剂量反应分析中，闲暇时间的体育活动每增加 3 MET 小时/周，EC 的风险降低约 2%（汇总 RR=0.98，p=0.02，95%CI=0.95-1.00，I(2)=53%，p（异质性）=0.06，三项病例对照研究和三项队列研究，3460 例，活动范围 0-50 MET 小时/周），每增加 1 小时/周，EC 的风险降低约 5%（汇总 RR=0.95，p<0.001，95%CI=0.93-0.98，I(2)=31%，p（异质性）=0.20，四项病例对照研究和两项队列研究，3314 例，活动范围 0-12 小时/周）。非线性剂量反应荟萃分析表明，该曲线可能在 10 MET 小时/周处趋于平稳（斜率变化的 p 值=0.04），但这种统计学意义对一项研究敏感。没有迹象表明小时/周呈非线性关联（斜率变化的 p 值>0.69）。总之，在 0-50 MET 小时/周或 0-15 小时/周的范围内，闲暇时间的体育活动增加可能会继续降低 EC 风险。未来的研究应该评估体育活动强度的独立作用和肥胖的影响修饰作用。
