Childhood and teenage physical activity and breast cancer risk
Adult physical activity is associated with reduced breast cancer risk, but few studies have evaluated activity before adulthood. Early life may be an important period because of rapid breast development and hormonal changes. This study contributes new information by examining childhood (ages 5–12) and teenage (ages 13–19) activity separately and overall.
The Sister Study is a cohort of 50,884 women aged 35–74. Women reported age 5–19 sports/exercise activities and age 10 and 16 unstructured activities. Both hours and MET-hours of activity were considered in association with breast cancer overall, by ER status, and by menopausal status. Hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated with Cox proportional hazards models.
2416 cases were diagnosed during follow-up (mean = 6.4 years). Participation in 7+ hours (vs <1 h) per week of sports/exercise during ages 5–19 was associated with reduced breast cancer risk (HR = 0.75; 95% CI 0.57–0.99). 7+ hours (vs <1 h) per week of unstructured physical activity at age 16, but not age 10, was inversely associated with breast cancer (HR = 0.81; 95% CI 0.70–0.95). Associations were more pronounced for ER+ tumors, especially for activity during the childhood (ages 5–12) period. Due to low correlation between childhood/teenage and adulthood activity in this study (r = 0.1), it is unlikely that recent activity explains our results.
Findings from this large cohort indicate higher levels of physical activity during ages 5–19 are inversely associated with breast cancer risk, supporting early life as a window of susceptibility for breast cancer development.
KeywordsChildhood Early life Physical activity Breast cancer
The authors appreciate the helpful review by Drs. Hazel Nichols and Lawrence Engel.
This work was supported by the National Institute of Environmental Health Sciences training grant to the University of North Carolina (T32ES007018) and by the Intramural Research Program of the NIH, National Institute of Environmental Health Sciences (Z01-ES044005).
Compliance with ethical standards
Conflict of interest
The authors declare they have no conflict of interest.
All procedures performed in studies involving human participants were in accordance with the ethical standards of Institutional Review Boards of the National Institute of Environmental Health Sciences, National Institutes of Health, and the Copernicus Group and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. This article does not contain any studies with animals performed by any of the authors.
Informed consent was obtained from all individual participants included in the Sister Study.
- 4.Kobayashi LC, Janssen I, Richardson H, Lai AS, Spinelli JJ, Aronson KJ (2013) Moderate-to-vigorous intensity physical activity across the life course and risk of pre- and post-menopausal breast cancer. Breast Cancer Res Treat 139(3):851–861. doi:10.1007/s10549-013-2596-9 CrossRefPubMedGoogle Scholar
- 7.Shoff SM, Newcomb PA, Trentham-Dietz A, Remington PL, Mittendorf R, Greenberg ER, Willett WC (2000) Early-life physical activity and postmenopausal breast cancer: effect of body size and weight change. Cancer Epidemiol Biomark Prev 9(6):591–595Google Scholar
- 11.Magnusson CM, Roddam AW, Pike MC, Chilvers C, Crossley B, Hermon C, McPherson K, Peto J, Vessey M, Beral V (2005) Body fatness and physical activity at young ages and the risk of breast cancer in premenopausal women. Br J Cancer 93(7):817–824. doi:10.1038/sj.bjc.6602758 CrossRefPubMedPubMedCentralGoogle Scholar
- 14.Margolis KL, Mucci L, Braaten T, Kumle M, Trolle Lagerros Y, Adami HO, Lund E, Weiderpass E (2005) Physical activity in different periods of life and the risk of breast cancer: the Norwegian-Swedish Women’s Lifestyle and Health cohort study. Cancer Epidemiol Biomark Prev 14(1):27–32Google Scholar
- 16.Peters TM, Moore SC, Gierach GL, Wareham NJ, Ekelund U, Hollenbeck AR, Schatzkin A, Leitzmann MF (2009) Intensity and timing of physical activity in relation to postmenopausal breast cancer risk: the prospective NIH-AARP diet and health study. BMC Cancer 9:349. doi:10.1186/1471-2407-9-349 CrossRefPubMedPubMedCentralGoogle Scholar
- 19.Physical Activity Guidelines for Americans (2008) US Department of Health and Human Services, Rockville, MDGoogle Scholar
- 20.Fakhouri TH, Hughes JP, Burt VL, Song M, Fulton JE, Ogden CL (2014) Physical activity in US youth aged 12–15 years, 2012. NCHS Data Brief 141:1–8Google Scholar
- 25.National Institute of Environmental Health Sciences (2016) Participation Rates for Annual and Detailed Follow-Ups. https://sisterstudy.niehs.nih.gov/English/tables.htm. Accessed 20 Jul 2016
- 26.National Institute of Environmental Health Sciences (2016). The Sister Study Outcome Validation. https://sisterstudy.niehs.nih.gov/English/validation.htm. Accessed 20 Jul 2016
- 29.Ajita A, Jiwanjot J (2014) Overweight and physical activity as a measure of age at menarche in females. Am J Sports Sci Med 2(1):32–34Google Scholar
- 33.Rothman KJ, Greenland S, Lash TL (2008) Modern epidemiology, 3rd edn. Lippincott Williams & Wilkins, PhiladelphiaGoogle Scholar