title: Impact of aerobic exercise on levels of IL-4 and IL-10: results from two randomized intervention trials.
abstract: The mechanisms whereby regular exercise reduces chronic inflammation remain unclear. We investigated whether regular aerobic exercise alters basal levels of interleukin (IL)-10 and IL-4 in two randomized trials of physical activity. The Alberta Physical Activity and Breast Cancer Prevention Trial (ALPHA, n = 320) and the Breast Cancer and Exercise Trial in Alberta (BETA, n = 400) were two-center, two-armed randomized trials in inactive, healthy, postmenopausal women. Both trials included an exercise intervention prescribed five times/week and no dietary changes. In ALPHA, the exercise group was prescribed 225 min/week versus no activity in the controls. BETA examined dose-response effects comparing 300 (HIGH) versus 150 (MODERATE) min/week. Plasma concentrations of IL-10 and IL-4 were measured at baseline, 6, and 12 months. Intention-to-treat (ITT) analysis was performed using linear mixed models adjusted for baseline biomarker concentrations. Circulating anti-inflammatory cytokine levels decreased among all groups, with percent change ranging from -3.4% (controls) to -8.2% (HIGH) for IL-4 and -1.6% (controls) to -7.5% (HIGH) for IL-10. No significant group differences were found for IL-4 (ALPHA P = 0.54; BETA P = 0.32) or IL-10 (ALPHA P = 0.84; BETA P = 0.68). Some evidence for moderation of the effect of exercise by baseline characteristics was found for IL-10 but not for IL-4. Results from these two large randomized aerobic exercise intervention trials suggest that aerobic exercise does not alter IL-10 or IL-4 in a manner consistent with chronic disease and cancer prevention.
authors.affiliation: Cancer Prevention Institute of California, Fremont, California.|University of California at Davis, Davis, California.
authors.forename: Shannon M
authors.initials: SM
authors.lastname: Conroy
authors.affiliation: Faculty of Physical Education and Recreation, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: Kerry S
authors.initials: KS
authors.lastname: Courneya
authors.affiliation: Department of Cancer Epidemiology and Prevention Research, CancerControl Alberta, Alberta Health Services, Calgary, Alberta, Canada.|Departments of Oncology and Community Health Sciences, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.
authors.forename: Darren R
authors.initials: DR
authors.lastname: Brenner
authors.affiliation: Department of Cancer Epidemiology and Prevention Research, CancerControl Alberta, Alberta Health Services, Calgary, Alberta, Canada.
authors.forename: Eileen
authors.initials: E
authors.lastname: Shaw
authors.affiliation: Department of Cancer Epidemiology and Prevention Research, CancerControl Alberta, Alberta Health Services, Calgary, Alberta, Canada.
authors.forename: Rachel
authors.initials: R
authors.lastname: O'Reilly
authors.affiliation: School of Public Health, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Yasui
authors.affiliation: Departments of Obstetrics and Gynaecology and Pediatrics, Dalhousie University, Halifax, Nova Scotia, Canada.
authors.forename: Christy G
authors.initials: CG
authors.lastname: Woolcott
authors.affiliation: Department of Cancer Epidemiology and Prevention Research, CancerControl Alberta, Alberta Health Services, Calgary, Alberta, Canada. christine.friedenreich@albertahealthservices.ca.|Departments of Oncology and Community Health Sciences, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada. christine.friedenreich@albertahealthservices.ca.
authors.forename: Christine M
authors.initials: CM
authors.lastname: Friedenreich
mesh_terms: D000368:Aged; D000416:Alberta / Q000453:epidemiology; D015415:Biomarkers; D001943:Breast Neoplasms / Q000097:blood / Q000453:epidemiology / Q000517:prevention & control; D016207:Cytokines / Q000097:blood; D015444:Exercise; D005260:Female; D006801:Humans; D018836:Inflammation Mediators / Q000097:blood; D016753:Interleukin-10 / Q000097:blood*; D015847:Interleukin-4 / Q000097:blood*; D008875:Middle Aged; D016032:Randomized Controlled Trials as Topic
chemical_list: D015415:Biomarkers; D016207:Cytokines; D018836:Inflammation Mediators; D016753:Interleukin-10; D015847:Interleukin-4
keywords: Aerobic exercise; anti-inflammatory markers; breast cancer; randomized controlled trial