The effects of screening on health behaviour: a summary of the results of randomized controlled trials.

BACKGROUND Screening aims to improve health by early detection of disease or risk factors for disease. It may also influence health behaviour, either by intention or as a side effect. The aim of this review was to summarize evidence of the effects of screening, either risk factor screening or screening for early detection of disease, on health behaviour: smoking habits, diet, exercise, alcohol consumption and adherence to guidelines for healthy living. METHODS This review included randomized controlled trials (RCTs) comparing the effects of screening on health behaviour in a screened group and an unscreened group. Systematic searches of Medline, CCTR and Embase between 1970 and May 2008 were conducted. RESULTS Seven trials were included, five on screening for risk factors (four cardiovascular; one ALDH2) and two on screening for early detection of disease (colorectal cancer and hearing loss). In trials of screening for risk factors, health behaviour was on average significantly more favourable in screened individuals. The number of trials on screening for early detection of disease was too small to allow for conclusions on effects on health behaviour. CONCLUSION The number of trials studying the effect of population-based screening programmes on health behaviour is limited. The trials on screening for risk factors suggest a positive effect on health behaviour, while the number of trials on screening for early detection of disease was too low to draw conclusions on subsequent health behaviour. Future RCTs of screening interventions should systematically include health behaviour effects in their study design.