title: Physical activity reduces breast cancer risk: a case-control study in Tunisia.
abstract: OBJECTIVE
  This study examined the relationship between lifetime history of physical activity and breast cancer risk.
  
  
  METHODS
  The case-control study was conducted on 400 women with histological confirmed breast cancer operated during the 2006-2009 period at Farhat Hached University Hospital, Sousse, Tunisia, and 400 cancer-free controls, aged 25-75 years. The physical activity was assessed using a structured questionnaire on each activity: type, duration, frequency, and intensity. Odds ratios (ORs), 95% confidence intervals (CI) and a full confounding assessment, included in this analysis, were derived using logistic regression.
  
  
  RESULTS
  These cases had lower lifetime averages for total physical activity for both forms of activity measurements (hours/week/year and MET-hours/week/year) and (P(trend)<0.001 and P(trend)=0.002, respectively). Significant risk reductions were found in total physical activity for both forms of activity measurements (OR=0.27, 95% CI: 0.18-0.52, OR=0.42, 95% CI: 0.26-0.73, respectively) for the highest versus the lowest level of activity (P(trend)=0.001 and 0.004, respectively). The stratification by menopausal status showed a significant 56% reduction in breast cancer risk for post-menopausal women (P(trend)=0.001, adjusted for age). The risk was further reduced to 68% (P(trend)=0.002, multivariate adjusted). Among pre-menopausal women, the total physical activity was not significantly associated with reduced risk, ORs were 0.88 (95% CI: 0.40-1.99, age adjusted) and 0.43 (95% CI: 0.12-1.38, multivariate adjusted).
  
  
  CONCLUSIONS
  These data are in concordance with the majority of previous reports which involved physical inactivity as an important risk factor for breast cancer.
authors.affiliation: Department of Medical Oncology, CHU Farhat Hached, Sousse 4000, Tunisia. awatefmsolly@gmail.com
authors.forename: Msolly
authors.initials: M
authors.lastname: Awatef
authors.forename: Gharbi
authors.initials: G
authors.lastname: Olfa
authors.forename: Chafai
authors.initials: C
authors.lastname: Rim
authors.forename: Kassab
authors.initials: K
authors.lastname: Asma
authors.forename: Mahmoudi
authors.initials: M
authors.lastname: Kacem
authors.forename: Hochlef
authors.initials: H
authors.lastname: Makram
authors.forename: Ben Fatma
authors.initials: BF
authors.lastname: Leila
authors.forename: Landolsi
authors.initials: L
authors.lastname: Amel
authors.forename: Ben Ahmed
authors.initials: BA
authors.lastname: Slim
mesh_terms: D000328:Adult; D000368:Aged; D001943:Breast Neoplasms / Q000453:epidemiology* / Q000517:prevention & control; D016022:Case-Control Studies; D015444:Exercise / Q000502:physiology*; D005260:Female; D006801:Humans; D008875:Middle Aged; D016017:Odds Ratio; D012307:Risk Factors; D011795:Surveys and Questionnaires; D014416:Tunisia