Correlates of changes in leisure time physical activity over 2 years: the Healthy Worker Project.
BACKGROUND: This study is the first to examine associations between concurrent changes in demongraphics, health behaviors, and physical activity in a free-living cohort of adults. METHODS: Surveys were conducted at 32 worksites (n = 3,672 workers) before and after a 2-year health promotion intervention. Associations between concurrent changes in sociodemographics, health, health behaviors, and physical activity were examined. Characteristics of individuals were also examined in four extreme physical activity change groupings: consistently very active, consistently very inactive, and changing from one extreme to the other over time. RESULTS: Among women, being married was associated with consistently low levels of physical activity, and increases in education were associated with increases in physical activity. Among both men and women, maintenance of single marital status was associated with increased physical activity levels, and increases in BMI were associated with decreases in physical activity. Increases in high-fat/calorie food intake were associated with increases in physical activity among men, but not among women. CONCLUSION: The observed associations indicate factors that may be important for understanding decreases in physical activity. The dynamic associations between changes in sociodemographics and physical activity demonstrate the need to examine changes in sociodemographics over time, rather than at only a single time point.