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Lifetime physical activity and the risk of breast cancer: a case-control study.
Cancer Detect Prev 2007; 31(1):18-28CD

Abstract

BACKGROUND

The association between breast cancer and lifetime histories of physical activity was studied to determine whether exercise may reduce development of this cancer.

METHODS

The case-control study was based on 250 women living in the Region of Western Pomerania with histological confirmed breast cancer operated during 1999-2003 in the Szczecin hospitals, and 301 controls, free of any cancer diagnosis, aged 35-75 years. Physical activity was assessed using a self-administered questionnaire with questions on type of activity, duration, frequency, and intensity for each type of activity. Data on physical activity from exercise/sports, household and outdoor chores, and occupational activity separately throughout a woman's lifetime were collected. Recreational physical activity was examined for the four age periods (14-20, 21-34, 35-50, and after the age of 50 years). Logistic regression was used to compute odds ratios (ORs) and 95% confidence intervals (CI) and a full assessment of confounding was included in analysis.

RESULTS

Lifetime total physical activity among all women was associated with a reduced breast cancer risk; after controlling for potential confounders the multivariate ORs associated with <110, 110-150, and >150 metabolic equivalent (MET)-hours/week/year were 1.00 (referent), 0.60 (95% CI: 0.60-1.06), and 0.43 (95% CI: 0.25-0.75), respectively (P(trend)=0.004). Analyses by type of lifetime activity for household and recreational activities revealed significant risk reductions: 1.00 (referent); 0.51, 95% CI: 0.29-0.87; 0.54, 95% CI: 0.31-0.94 (P(trend)=0.002), and 1.00 (referent); 0.54, 95% CI: 0.31-0.94; 0.40, 95% CI: 0.22-0.70 (P(trend)<0.001), respectively. For lifetime occupational activity a modest association could not be ruled out when measured the activity by average annual hours/week; the ORs were 0.51, 95% CI: 0.29-0.91, and 0.58, 95% CI: 0.33-1.00, the inverse trend in risk was not significant (P(trend)=0.51). Women who started recreational activity after age of 20 years had much more higher breast cancer risk than either those who were active between ages 14 and 20 years and were inactive after age 20 years or continued their activity throughout adult life.

CONCLUSIONS

These data are in concordance with the hypothesis that lifetime total physical activity is associated with decreased breast cancer risk. They also suggest that recreational physical activity at ages 14-20 years is the most beneficial. In addition, these findings confirm the majority of previous reports which implicated physical inactivity as important risk factor for breast cancer.

Authors+Show Affiliations

Institute of Physical Education, Faculty of Natural Sciences, University of Szczecin, Al. Piastów 40 b/6, 71-065 Szczecin, Poland. joanna.kruk@univ.szczecin.pl

Pub Type(s)

Journal Article

Language

eng

PubMed ID

17296272

Citation

Kruk, Joanna. "Lifetime Physical Activity and the Risk of Breast Cancer: a Case-control Study." Cancer Detection and Prevention, vol. 31, no. 1, 2007, pp. 18-28.
Kruk J. Lifetime physical activity and the risk of breast cancer: a case-control study. Cancer Detect Prev. 2007;31(1):18-28.
Kruk, J. (2007). Lifetime physical activity and the risk of breast cancer: a case-control study. Cancer Detection and Prevention, 31(1), pp. 18-28.
Kruk J. Lifetime Physical Activity and the Risk of Breast Cancer: a Case-control Study. Cancer Detect Prev. 2007;31(1):18-28. PubMed PMID: 17296272.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Lifetime physical activity and the risk of breast cancer: a case-control study. A1 - Kruk,Joanna, Y1 - 2007/02/12/ PY - 2006/12/06/accepted PY - 2007/2/14/pubmed PY - 2007/8/19/medline PY - 2007/2/14/entrez SP - 18 EP - 28 JF - Cancer detection and prevention JO - Cancer Detect. Prev. VL - 31 IS - 1 N2 - BACKGROUND: The association between breast cancer and lifetime histories of physical activity was studied to determine whether exercise may reduce development of this cancer. METHODS: The case-control study was based on 250 women living in the Region of Western Pomerania with histological confirmed breast cancer operated during 1999-2003 in the Szczecin hospitals, and 301 controls, free of any cancer diagnosis, aged 35-75 years. Physical activity was assessed using a self-administered questionnaire with questions on type of activity, duration, frequency, and intensity for each type of activity. Data on physical activity from exercise/sports, household and outdoor chores, and occupational activity separately throughout a woman's lifetime were collected. Recreational physical activity was examined for the four age periods (14-20, 21-34, 35-50, and after the age of 50 years). Logistic regression was used to compute odds ratios (ORs) and 95% confidence intervals (CI) and a full assessment of confounding was included in analysis. RESULTS: Lifetime total physical activity among all women was associated with a reduced breast cancer risk; after controlling for potential confounders the multivariate ORs associated with <110, 110-150, and >150 metabolic equivalent (MET)-hours/week/year were 1.00 (referent), 0.60 (95% CI: 0.60-1.06), and 0.43 (95% CI: 0.25-0.75), respectively (P(trend)=0.004). Analyses by type of lifetime activity for household and recreational activities revealed significant risk reductions: 1.00 (referent); 0.51, 95% CI: 0.29-0.87; 0.54, 95% CI: 0.31-0.94 (P(trend)=0.002), and 1.00 (referent); 0.54, 95% CI: 0.31-0.94; 0.40, 95% CI: 0.22-0.70 (P(trend)<0.001), respectively. For lifetime occupational activity a modest association could not be ruled out when measured the activity by average annual hours/week; the ORs were 0.51, 95% CI: 0.29-0.91, and 0.58, 95% CI: 0.33-1.00, the inverse trend in risk was not significant (P(trend)=0.51). Women who started recreational activity after age of 20 years had much more higher breast cancer risk than either those who were active between ages 14 and 20 years and were inactive after age 20 years or continued their activity throughout adult life. CONCLUSIONS: These data are in concordance with the hypothesis that lifetime total physical activity is associated with decreased breast cancer risk. They also suggest that recreational physical activity at ages 14-20 years is the most beneficial. In addition, these findings confirm the majority of previous reports which implicated physical inactivity as important risk factor for breast cancer. SN - 0361-090X UR - https://www.unboundmedicine.com/medline/citation/17296272/Lifetime_physical_activity_and_the_risk_of_breast_cancer:_a_case_control_study_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0361-090X(06)00230-3 DB - PRIME DP - Unbound Medicine ER -