Physical activity, Body Mass Index and health care costs in mid-age Australian women.

OBJECTIVE: This study examined the relationships between combined categories of physical activity (PA) and Body Mass Index (BMI) with health care costs in women and assessed the potential cost savings of improving PA and BMI in sedentary mid-age women.
METHODS: Cross-sectional analysis of 2001 survey data linked to health service use data for the same year from 7,004 mid-age women (50-55 years) participating in the Australian Longitudinal Study on Women's Health.
RESULTS: The mean (median; interquartile range) annual cost of Medicare-subsidised services was $542 (355; 156-693) per woman. Costs were 17% higher in obese than in healthy-weight women and 26% higher in sedentary than in moderately active women. For sedentary obese women, mean costs were 43% higher than in healthy weight, moderately active women. After adjustment for potential confounders, the relative risk of 'high' claims (>or=15 claims per year) for overweight women who reported 'moderate' or 'high' PA were lower than for women with healthy BMI who reported no PA. CONCLUSIONS AND IMPLICATIONS: Lower PA and higher BMI are both associated with higher health care costs, but costs are lower for overweight active women than for healthy-weight sedentary women. At the population level these data suggest that there would be significant cost savings if all sedentary mid-age women could achieve at least 'low' levels of PA (60-150 minutes a week).