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Recreational and occupational physical activities and risk of breast cancer.
J Natl Cancer Inst 1998; 90(2):100-17JNCI

Abstract

Physical activity has been hypothesized to reduce breast cancer risk, but an inverse association has not been consistently reported. In this review, we critically evaluate for coherence, validity, and bias the epidemiologic studies on recreational or occupational physical activity, discuss the biologic plausibility of the association, and identify areas for future research. Results from seven of nine studies suggest that higher levels of occupational physical activity may be associated with a reduction in risk, at least among a subgroup of women. Eleven of 16 investigations on recreational exercise reported a 12%-60% decrease in risk among premenopausal and postmenopausal women, although a dose-response trend was not evident in most of the studies. The reduction in risk associated with exercise was more likely to be observed in case-control studies than in cohort studies. Most investigations incompletely assessed physical activity, which contributed to conflicting findings on the optimal time period, duration, frequency, or intensity of activity to minimize risk. Physical activity may exert its effects through changes in menstrual characteristics, reduced body size, or alterations in immune function. In summary, most epidemiologic studies of physical activity reported a reduction in the risk of breast cancer among physically active women. Future research studies should focus on using a cohort design to rule out recall bias as a possible explanation for the decrease in risk associated with exercise, on improving assessment of lifetime physical activity from all sources to clarify whether there is a dose-response relation or an optimal time period, duration, frequency, or intensity of activity, and on elucidating the underlying mechanisms for the inverse association.

Authors+Show Affiliations

Columbia University School of Public Health, Division of Epidemiology, New York, NY 10032, USA.No affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Review

Language

eng

PubMed ID

9450570

Citation

Gammon, M D., et al. "Recreational and Occupational Physical Activities and Risk of Breast Cancer." Journal of the National Cancer Institute, vol. 90, no. 2, 1998, pp. 100-17.
Gammon MD, John EM, Britton JA. Recreational and occupational physical activities and risk of breast cancer. J Natl Cancer Inst. 1998;90(2):100-17.
Gammon, M. D., John, E. M., & Britton, J. A. (1998). Recreational and occupational physical activities and risk of breast cancer. Journal of the National Cancer Institute, 90(2), pp. 100-17.
Gammon MD, John EM, Britton JA. Recreational and Occupational Physical Activities and Risk of Breast Cancer. J Natl Cancer Inst. 1998 Jan 21;90(2):100-17. PubMed PMID: 9450570.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Recreational and occupational physical activities and risk of breast cancer. AU - Gammon,M D, AU - John,E M, AU - Britton,J A, PY - 1998/2/5/pubmed PY - 1998/2/5/medline PY - 1998/2/5/entrez SP - 100 EP - 17 JF - Journal of the National Cancer Institute JO - J. Natl. Cancer Inst. VL - 90 IS - 2 N2 - Physical activity has been hypothesized to reduce breast cancer risk, but an inverse association has not been consistently reported. In this review, we critically evaluate for coherence, validity, and bias the epidemiologic studies on recreational or occupational physical activity, discuss the biologic plausibility of the association, and identify areas for future research. Results from seven of nine studies suggest that higher levels of occupational physical activity may be associated with a reduction in risk, at least among a subgroup of women. Eleven of 16 investigations on recreational exercise reported a 12%-60% decrease in risk among premenopausal and postmenopausal women, although a dose-response trend was not evident in most of the studies. The reduction in risk associated with exercise was more likely to be observed in case-control studies than in cohort studies. Most investigations incompletely assessed physical activity, which contributed to conflicting findings on the optimal time period, duration, frequency, or intensity of activity to minimize risk. Physical activity may exert its effects through changes in menstrual characteristics, reduced body size, or alterations in immune function. In summary, most epidemiologic studies of physical activity reported a reduction in the risk of breast cancer among physically active women. Future research studies should focus on using a cohort design to rule out recall bias as a possible explanation for the decrease in risk associated with exercise, on improving assessment of lifetime physical activity from all sources to clarify whether there is a dose-response relation or an optimal time period, duration, frequency, or intensity of activity, and on elucidating the underlying mechanisms for the inverse association. SN - 0027-8874 UR - https://www.unboundmedicine.com/medline/citation/9450570/Recreational_and_occupational_physical_activities_and_risk_of_breast_cancer_ L2 - https://academic.oup.com/jnci/article-lookup/doi/10.1093/jnci/90.2.100 DB - PRIME DP - Unbound Medicine ER -