A systematic review of the relationship between socio-economic position and physical activity

Objective: The aim of the present review was to examine epidemiological evidence to determine if there is strong evidence of a positive gradient of increasing physical activity across the socio-economic strata, and how relationships are affected by socio-economic measurement. Design: Systematic review. Method: A search of major databases was conducted to identify published studies that reported physical activity in relation to socio-economic position (SEP) in adults. Results: Twenty-eight cross-sectional and five longitudinal studies met the inclusion criteria. Approximately half of these were American. Consequently education and income were most commonly used to represent SEP. The majority of studies were secondary analyses of existing health survey data, which could explain the generally large sample sizes and methodological weaknesses in physical activity and SEP measurement. There was consistent evidence of a higher prevalence or higher levels of leisure-time or moderate-vigorous intensity physical activity in those at the top of the socio-economic strata compared with those at the bottom. Evidence for positive gradients across the socio-economic strata was less consistent. Education produced the most stable relationships, less susceptible to confounding effects of ethnicity and the environment. Conclusion: Those at the top of the socio-economic scale appear to perform more leisure-time activity than those at the bottom. Diverse and often crude physical activity and socio-economic measurement made it difficult to distinguish between artefact and true effect in a relationship with so many potential confounding influences. Further studies using up-to-date methods of socio-economic and physical activity measurement are necessary to further explore this relationship and its confounders.