title: Physical activity and the risk of breast cancer in BRCA1/2 mutation carriers.
abstract: BRCA1/2 mutation carriers have a high lifetime risk of developing breast cancer. Differences in penetrance indicate that this risk may be influenced by lifestyle factors. Because physical activity is one of the few modifiable risk factors, it may provide a target to add to breast cancer prevention in this high-risk population. We examined the association between self-reported lifetime sports activity and breast cancer risk in a nationwide retrospective cohort study, including 725 carriers, of whom 218 had been diagnosed with breast cancer within 10 years prior to questionnaire completion. We found a nonsignificantly decreased risk for ever engaging in sports activity (HR = 0.84, 95%CI = 0.57-1.24). Among women who had participated in sports, a medium versus low level of intensity and duration (i.e., between 11.0 and 22.7 mean MET hours/week averaged over a lifetime) reduced the risk of breast cancer (HR = 0.59, 95%CI = 0.36-0.95); no dose-response trend was observed. For mean hours/week of sports activity, a nonsignificant trend was observed (HR(low versus never) = 0.93, 95%CI = 0.60-1.43; HR(medium versus never) = 0.81, 95%CI = 0.51-1.29; HR(high versus never) = 0.78, 95%CI = 0.48-1.29; p (trend overall) = 0.272; p (trend active women) = 0.487). For number of years of sports activity no significant associations were found. Among women active in sports before age 30, mean MET hours/week showed the strongest inverse association of all activity measures (HR(medium versus low) = 0.60, 95%CI = 0.38-0.96; HR(high versus low) = 0.58, 95%CI = 0.35-0.94; p (trend) = 0.053). Engaging in sports activity after age 30 was also inversely associated with breast cancer risk (HR = 0.63, 95%CI = 0.44-0.91). Our results indicate that sports activity may reduce the risk of breast cancer in BRCA1/2 mutation carriers.
authors.affiliation: Department of Epidemiology, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX, Amsterdam, The Netherlands. a.pijpe@nki.nl
authors.forename: Anouk
authors.initials: A
authors.lastname: Pijpe
authors.forename: Peggy
authors.initials: P
authors.lastname: Manders
authors.forename: Richard M
authors.initials: RM
authors.lastname: Brohet
authors.forename: J Margriet
authors.initials: JM
authors.lastname: Collée
authors.forename: Senno
authors.initials: S
authors.lastname: Verhoef
authors.forename: Hans F A
authors.initials: HF
authors.lastname: Vasen
authors.forename: Nicoline
authors.initials: N
authors.lastname: Hoogerbrugge
authors.forename: Christi J
authors.initials: CJ
authors.lastname: van Asperen
authors.forename: Charlotte
authors.initials: C
authors.lastname: Dommering
authors.forename: Margreet G E M
authors.initials: MG
authors.lastname: Ausems
authors.forename: Cora M
authors.initials: CM
authors.lastname: Aalfs
authors.forename: Encarna B
authors.initials: EB
authors.lastname: Gomez-Garcia
authors.forename: Laura J
authors.initials: LJ
authors.lastname: Van't Veer
authors.forename: Flora E
authors.initials: FE
authors.lastname: van Leeuwen
authors.forename: Matti A
authors.initials: MA
authors.lastname: Rookus
mesh_terms: D000328:Adult; D001943:Breast Neoplasms / Q000453:epidemiology* / Q000235:genetics*; D015444:Exercise / Q000502:physiology*; D005260:Female; D019398:Genes, BRCA1; D024522:Genes, BRCA2; D006579:Heterozygote; D006801:Humans; D008875:Middle Aged; D009154:Mutation; D012307:Risk Factors