Moderate physical activity and breast cancer risk:  the effect of menopausal status.
BACKGROUND
It has been suggested that both moderate-and vigorous-intensity physical activity reduces the risk of breast cancer. However, the effect of moderate-intensity physical activity on breast cancer risk has not been consistently evaluated by menopausal status and has not been evaluated in Mexican women.


OBJECTIVE
To evaluate the effect of moderate-intensity physical activity (h/week and MET-h/week) on the risk of breast cancer by menopausal status in Mexican women.


METHODS
A population-based case-control study was conducted in Mexico. One thousand incident cases and 1,074 matched controls to cases by 5 years of age, site and health institution participated in the study. Women provided information on health, diet and physical activity by means of an in-person interview. Anthropometric measurements and blood samples were obtained from all women. A conditional logistic regression model was used to assess this association.


RESULTS
Participating in moderate-intensity physical activity decreased the risk of BC in both pre- and postmenopausal women (OR = 0.96; 95% CI 0.92.-0.99; OR = 0.90; 95% CI 0.86-0.93, respectively) for every 3 h per week of moderate-intensity physical activity. There was a statistically significant modification effect by menopausal status (p = 0.009).


CONCLUSIONS
Strategies need to be identified that will engage women in physical activity programs.
Angeles-Llerenas
Angélica
A
Instituto Nacional de Salud Pública, Centro de Investigaciones en Salud Poblacional, Avenida Universidad 655, Col. Santa María Ahuacatitlán, 62508 Cuernavaca, Morelos, México.
Ortega-Olvera
Carolina
C
Pérez-Rodríguez
Edelmiro
E
Esparza-Cano
Jesús Pablo
JP
Lazcano-Ponce
Eduardo
E
Romieu
Isabelle
I
Torres-Mejía
Gabriela
G
D000328:Adult; D015992:Body Mass Index; D001943:Breast Neoplasms / Q000453:epidemiology / Q000503:physiopathology* / Q000517:prevention & control; D016022:Case-Control Studies; D015444:Exercise / Q000502:physiology*; D006801:Humans; D015994:Incidence; D016015:Logistic Models; D008593:Menopause / Q000502:physiology*; D008800:Mexico / Q000453:epidemiology; D008875:Middle Aged; D016017:Odds Ratio; D012307:Risk Factors; D012907:Smoking; D011795:Surveys and Questionnaires; D013997:Time Factors