Interventions for promoting physical activity.
Hillsdon M., Foster C., Thorogood M.
BACKGROUND: Little is known about the effectiveness of strategies to enable people to achieve an increase in their physical activity. OBJECTIVES: To assess the effects of interventions for promoting physical activity in adults aged 16 years and older, not living in an institution. SEARCH STRATEGY: We searched CENTRAL (Issue 4, 2001), MEDLINE, EMBASE, CINAHL, PsychLIT, BIDS ISI, SPORTDISCUS, SIGLE, SCISEARCH (from earliest date available to December 2001) and reference lists of articles. SELECTION CRITERIA: Randomised, controlled, trials comparing different interventions to encourage sedentary adults not living in an institution to become physically active. Studies required a minimum of six months follow up from the start of the intervention to the collection of final data and either used an intention to treat analysis or, failing that, had no more than 20% loss to follow up. DATA COLLECTION AND ANALYSIS: At least two reviewers independently assessed each study quality and extracted data. Study authors were contacted for additional information where necessary. Standardised mean differences and 95% confidence intervals were calculated for continuous measures of self reported physical activity and cardio-respiratory fitness. For studies with dichotomous outcomes, odds ratios and 95% confidence intervals were calculated. MAIN RESULTS: The effect of interventions on self reported physical activity (11 studies; 3940 participants) was positive and moderate, with a pooled standardised mean difference of 0.31 (95% CI 0.12 to 0.50), as was the effect on cardio-respiratory fitness (7 studies; 1406 participants) pooled SMD 0.4 (95% CI 0.09 to 0.70). The effect of interventions in achieving a predetermined threshold of physical activity (6 studies; 2313 participants) was not significant with an odds ratio of 1.30 (95% CI 0.87 to 1.95). There was significant heterogeneity in the reported effects as well as heterogeneity in characteristics of the interventions. The heterogeneity in reported effects was reduced in higher quality studies, when physical activity was self-directed with some professional guidance and when there was on-going professional support. AUTHORS' CONCLUSIONS: Our review suggests that physical activity interventions have a moderate effect on self reported physical activity and cardio-respiratory fitness, but not on achieving a predetermined level of physical activity. Due to the clinical and statistical heterogeneity of the studies, only limited conclusions can be drawn about the effectiveness of individual components of the interventions. Future studies should provide greater detail of the components of interventions.