Physical activity and risk of breast cancer in premenopausal women
2003

Physical Activity and Breast Cancer Risk in Premenopausal Women

Sample size: 110468 publication 10 minutes Evidence: moderate

Author Information

Author(s): Colditz G A, Feskanich D, Chen W Y, Hunter D J, Willett W C

Primary Institution: Harvard School of Public Health

Hypothesis

Does physical activity reduce the risk of breast cancer in premenopausal women?

Conclusion

The study found no overall association between physical activity and the risk of invasive breast cancer among premenopausal women.

Supporting Evidence

  • Women who ran or jogged for 2 or more hours per week had a nonsignificant reduction in breast cancer risk.
  • Total physical activity was unrelated to breast cancer risk.
  • Among obese women, higher activity levels were associated with increased risk of breast cancer.

Takeaway

This study looked at whether being active helps prevent breast cancer in younger women, and it found that being active didn't really make a difference.

Methodology

The study analyzed data from the Nurses' Health Study II, which included 110,468 premenopausal women who reported their physical activity levels and were followed for breast cancer diagnoses over 10 years.

Potential Biases

Self-reported physical activity may introduce reporting bias.

Limitations

The study may not have sufficient power to detect associations due to low levels of certain activities like running or jogging among participants.

Participant Demographics

Participants were predominantly premenopausal women aged 25 to 42 years, primarily registered nurses.

Statistical Information

P-Value

0.57

Confidence Interval

95% CI 0.44–0.75

Statistical Significance

p<0.05

Digital Object Identifier (DOI)

10.1038/sj.bjc.6601175

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