Introducing The Physical Activity Longitudinal Study

Abstract

Substantial evidence has been accumulated on the health benefits of physical activity. However, the relative contributions of individual and environmental determinants of lifetime participation are poorly understood. PURPOSE To outline the background and methods of the Physical Activity Longitudinal Study (PALS), a follow-up study that was undertaken to examine the individual- and neighborhood-level influences on long-term participation in physical activity and its relationship to health outcomes. METHODS The sample was a representative, population- and place-based cohort consisting of 4904 individuals in families participating in the 1981 Canada Fitness Survey and 1988 Campbell's Survey of Well Being. Information on leisure-time physical activity was collected at baseline (1981) and about 20-years later using a validated adaptation of the Minnesota Leisure Time Physical Activity Questionnaire. Self-rated health status was gathered at all time points; self-reported chronic conditions were recorded in 1988 and 2002–4, and physical functioning, bodily pain, vitality, mental health, and physical role limitations were assessed in 2002–4 using a standard scale (SF36). Height and weight were self-reported in 2002–4 and were measured in 1981 and 1988 using the Canadian Standardized Test of Fitness (including waist circumference, aerobic fitness, sit-ups and pushups). Environmental data collected in 2002–4 included neighborhood socio-economic status, social cohesion, and urban form (mixed use, safety, traffic, etc). The place-based design provided data on degree of urbanization at each time point. RESULTS After extensive tracing activities, 2511 individuals provided self-reported data between November 2002 and April 2004. An estimated 899 among the 4904 persons eligible were deceased, which is being confirmed by mortality record linkage; 32 were unable to participate due to health reasons; 973 refused; and the remaining 489 were lost to follow-up. This yields an overall non-response rate of 29.8% over the 20-year period. No differences were observed in the 1981 profile of participants compared to the eligible cohort (physical activity, other lifestyle, health, median income, housing) although fewer respondents than non-respondents smoked or were underweight at baseline. CONCLUSION Results emanating from the population and place perspective of PALS should help inform policy development on socio-environmental factors to promote physical activity and population health. Results will be released through conferences and Publications beginning in 2006.