[Factors associated with physical activity in the Portuguese population]

To evaluate the association between demographic, social and behavior characteristics and different types of physical activity.

A total of 37.692 subjects of a representative sample of the Portuguese population were studied as part of the National Health Survey in 1998 and 1999. Most were females (53.1%) aged>or=20 years. Daily physical activity was self-reported based on a questionnaire and discriminated in different types: total physical activity, leisure-time and exercise. Each type of physical activity was dichotomized into low (light/moderate) and high intensity (heavy/very heavy). Odds ratios (OR) and 95% confidence intervals were estimated using unconditional logistic regression.

In both men and women, a significant inverse association between age and different types of physical activity and between obesity and leisure time physical activity and exercise was seen. A positive association was found between education (or=12 years) and leisure-time PA (OR 1; 1.58; 2.39 in females and 1; 1.44; 2.08 in males) and exercise (OR 1; 3.50; 9.77 in females and 1; 3.42; 7.61 in males) and an inverse association with total physical activity (OR 1; 0.65; 0.20 in females and 1; 0.47; 0.09 in males) was found. Regardless of age, single subjects were frequently more active. Alcohol consumption in both men and women and tobacco consumption in males were negatively associated with leisure-time physical activity.

Youngest, normal weighted, single, non-drinkers subjects and non-smokers males were more likely to be physically active. In both men and women, there was a clear effect of education on the type of physical activity.