Physical activity and breast cancer risk among Asian-American women in Los Angeles: a case-control study

Cancer. 2003 May 15;97(10):2565-75. doi: 10.1002/cncr.11364.


Background: To the authors' knowledge, there have been few studies published to date regarding physical activity patterns and breast cancer risk in Asian and Asian-American women.

Methods: The authors conducted a population-based case-control study of 501 Asian-American women with incident breast cancer and a control group of 594 Asian-American women in Los Angeles County to evaluate the role of lifetime physical activity on breast cancer risk. Information concerning lifetime recreational physical activity (i.e., type of activity, duration [years], and frequency [average hours per week]) and occupational physical activity was obtained using a structured questionnaire that was administered in person.

Results: Increasing years and levels (average metabolic equivalent [MET] hours per week) of lifetime recreational activity were associated with a significantly reduced risk of breast cancer after adjusting for demographic factors, migration history, and menstrual and reproductive factors. Compared with women who had no lifetime recreational physical activity, <or= 3 MET hours per week, > 3-6 MET hours per week, > 6-12 MET hours per week, and > 12 MET hours per week of activity were associated with significantly reduced risk, with odds ratios (and 95% confidence intervals) of 0.91 (0.55-1.49), 0.65 (0.39-1.10), 0.53 (0.31-0.90), and 0.47 (0.28-0.80), respectively (P value for trend < 0.001). The risk of breast cancer was associated inversely with occupational physical activity, although the result was not statistically significant.

Conclusions: The findings of the current study provide further support for the finding that physical activity has a protective role in breast cancer.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adult
  • Age Distribution
  • Aged
  • Asian Americans / statistics & numerical data*
  • Breast Neoplasms / epidemiology*
  • Breast Neoplasms / ethnology
  • Breast Neoplasms / etiology*
  • Breast Neoplasms / prevention & control
  • Case-Control Studies
  • Employment
  • Exercise*
  • Female
  • Humans
  • Interviews as Topic
  • Los Angeles / epidemiology
  • Middle Aged
  • Risk Factors