Development of a population-based microsimulation mode of physical activity in Canada.

Computer simulation modeling makes it possible to project physical activity levels and the prevalence of related health outcomes. Such projections can help to inform programs that aim to increase physical activity levels and improve population health.The Population Health Model (POHEM) platform was used to develop a dynamic microsimulation model of physical activity among Canadian adults. Key parameters were derived from the National Population Health Survey (1994/1995 to 2006/2007) and the 2000/2001 Canadian Community Health Survey. To assess the validity of the physical activity module (POHEM-PA), estimates from the simulation projections were compared with results from nationally representative surveys.Trends over time in physical activity levels, chronic disease prevalence, and Health Utilities Index based on POHEM-PA projections were similar to those based on data from subsequent cycles of the Canadian Community Health Survey.The addition of a physical activity module to POHEM provides a tool that can improve understanding of the complex dynamics underlying the relationship between physical activity and health outcomes as a population ages.