PHYSICAL-ACTIVITY AND BREAST-CANCER RISK

Data from a multicentric case-control study on breast cancer conducted in Italy were used to analyze the relationship of occupational and le isure-time physical activity with breast cancer risk, Cases were 2569 histologically confirmed incident breast cancer cases, and controls we re 2588 patients admitted to the same network of hospitals:of cases fo r acute, nonneoplastic, non-hormone related diseases, After allowance for major identified potential confounding factors (including an estim ate of total calorie intake), the odds ratios (ORs) were 0.70, 0.71, 0 .64, and 0.54 in subsequent levels of physical activity at work at age s 30-39, compared to the lowest level, The association was similar for occupational physical activity at ages 15-19 and still apparent at ag es 50-59, with risk estimates of 0.86, 0.85, 0.85, and 0.62, The ORs f or the highest versus the lowest category of leisure-time physical act ivity were also below unity (ORs for the highest level of leisure-time physical activity at ages 15-19, 0.95; at ages 30-39, 0.76; and at ag es 50-59, 0.66), The protection of physical activity was apparently st ronger below age 60 at diagnosis and was consistent across the strata of selected covariates, although the protection was somewhat greater f or more educated women.