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Leisure‐time physical activity and endometrial cancer risk: Dose–response meta‐analysis of epidemiological studies
Author(s) -
Keum NaNa,
Ju Woong,
Lee Dong Hoon,
Ding Eric L.,
Hsieh Chung C.,
Goodman Julie E.,
Giovannucci Edward L.
Publication year - 2014
Publication title -
international journal of cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.475
H-Index - 234
eISSN - 1097-0215
pISSN - 0020-7136
DOI - 10.1002/ijc.28687
Subject(s) - medicine , meta analysis , relative risk , confidence interval , cohort study , metabolic equivalent , endometrial cancer , epidemiology , cohort , observational study , physical activity , demography , cancer , physical therapy , sociology
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.