The impact of screening on future health-promoting behaviours and health beliefs: a systematic review.

OBJECTIVES: To carry out a systematic review to examine the effects of cholesterol, breast and cervical cancer screening on actual or intended health-promoting behaviours and health-related beliefs. DATA SOURCES: Eleven electronic databases (between 1980 and 2000). REVIEW
METHODS: All English language studies that investigated the impact of cholesterol, breast and cervical screening programmes on health-promoting behaviours and beliefs were assessed for inclusion. The data extraction form and quality assessment criteria were developed using the NHS Centre for Reviews and Dissemination guidelines. Data were extracted and a non-quantitative synthesis was conducted. Reviewers categorised the outcomes into those that could be considered beneficial or detrimental to health. This categorisation was based on a value judgement that considered both statistical and clinical significance.
RESULTS: The cholesterol studies used prospective designs more frequently, possibly as many focused on observing changes in lifestyle following screening. Participants who went for breast or cervical screening were not offered advice on lifestyle changes and most of the research into cancer screening programmes investigated issues related to uptake of screening services, explanations of why people are or are not screened and interventions to improve uptake. All three screening programmes are associated with high levels of favourable health behaviours and beliefs that have been measured, although there is evidence that recommended follow-up after screening is often not adhered to. There was no literature on the cost-effectiveness regarding the wider implications of screening (only on reduction of disease-specific mortality/morbidity), possibly due to the outcomes being very broad and not easily categorised and classified.
CONCLUSIONS: The studies reviewed suggest that cholesterol screening had a positive effect on health behaviours, although participation was voluntary and those screened were possibly more motivated to make changes. These results are therefore not generalisable to the entire population and other factors need to be taken into account. Reduction in blood cholesterol levels was reported in all but two of the studies that assessed this outcome, suggesting that successful lifestyle changes were made. However, as most of the studies only reported follow-up of those screened, some of the reduction can be attributable to regression to the mean. Whether breast and cervical screening affect future health behaviours and beliefs has not been directly measured in many studies and few studies have collected baseline measures. However, evidence suggests that women who attend breast and cervical screening once are likely to reattend and attendance is associated with several positive health behaviours, although it cannot be confirmed whether the associations observed were a result of screening or because these women have a certain set of health behaviours and beliefs irrespective of their experience of screening. Areas of further research include: measuring a much wider range of behaviours and beliefs before and after screening is accepted or declined, examining the subgroup of participants who receive 'desirable' results and the impact of this on health beliefs and health-promoting behaviour, and qualitative research into the experiences of screening and how this interacts with knowledge and beliefs about other aspects of health.