Browsing by keyword "Recreation"

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    • Recreational physical activity and the risk of breast cancer in postmenopausal women: the Women's Health Initiative Cohort Study
      McTiernan, Anne; Kooperberg, Charles L.; White, Emily; Wilcox, Sara; Coates, Ralph; Adams-Campbell, Lucile L.; Woods, Nancy F.; Ockene, Judith K. (2003-09-10)
      CONTEXT: Women who are physically active have a decreased risk for breast cancer, but the types, amounts, and timing of activity needed are unknown. OBJECTIVE: To prospectively examine the association between current and past recreational physical activity and incidence of breast cancer in postmenopausal women. DESIGN, SETTING, PATIENTS: Prospective cohort study in 74 171 women aged 50 to 79 years who were recruited by 40 US clinical centers from 1993 through 1998. MAIN OUTCOME MEASURE: Incident invasive and in situ breast cancer. RESULTS: We documented 1780 newly diagnosed cases of breast cancer over a mean follow-up of 4.7 years. Compared with less active women, women who engaged in regular strenuous physical activity at age 35 years had a 14% decreased risk of breast cancer (relative risk [RR], 0.86; 95% confidence interval [CI], 0.78-0.95). Similar but attenuated findings were observed for strenuous physical activity at ages 18 years and 50 years. An increasing total current physical activity score was associated with a reduced risk for breast cancer (P =.03 for trend). Women who engaged in the equivalent of 1.25 to 2.5 hours per week of brisk walking had an 18% decreased risk of breast cancer (RR, 0.82; 95% CI, 0.68-0.97) compared with inactive women. Slightly greater reduction in risk was observed for women who engaged in the equivalent of 10 hours or more per week of brisk walking. The effect of exercise was most pronounced in women in the lowest tertile of body mass index (BMI) (CONCLUSIONS: These data suggest that increased physical activity is associated with reduced risk for breast cancer in postmenopausal women, longer duration provides most benefit, and that such activity need not be strenuous.

    • Sources of variance in daily physical activity levels in the seasonal variation of blood cholesterol study
      Matthews, Charles E.; Hebert, James R.; Freedson, Patty S.; Stanek, Edward J.; Merriam, Philip A.; Ebbeling, Cara B.; Ockene, Ira S. (2001-06-01)
      The authors examined sources of variance in self-reported physical activity in a cohort of healthy adults (n = 580) from Worcester, Massachusetts (the Seasonal Variation of Blood Cholesterol Study, 1994-1998). Fifteen 24-hour physical activity recalls of total, occupational, and nonoccupational activity (metabolic equivalent-hours/day) were obtained over 12 months. Random effects models were employed to estimate variance components for subject, season, day of the week, and residual error, from which the number of days of assessment required to achieve 80% reliability was estimated. The largest proportional source of variance in total and nonoccupational activity was within-subject variance (50-60% of the total). Differences between subjects accounted for 20-30% of the overall variance in total activity, and seasonal and day-of-the-week effects accounted for 6% and 15%, respectively. For total activity, 7-10 days of assessment in men and 14-21 days of assessment in women were required to achieve 80% reliability. For nonoccupational activity, 21-28 days of assessment were required. This study is among the first to have examined the sources of variance in daily physical activity levels in a large population of adults using 24-hour physical activity recall. These findings provide insight for understanding the strengths and limitations of short term and long term physical activity assessments employed in epidemiologic studies.