Using the theory of planned behaviour to predict screening uptake in two contexts

Abstract
Given current policy that decisions about screening should be based on informed choice, such decisions should reflect people's values and attitudes. This prospective study compares the attitudes and other cognitive predictors of screening uptake in two contexts: when conducted as part of a routine visit and when it is conducted at a separate, test-specific visit. It was conducted in two hospitals in England, differing in method of screening organisation. 1499 pregnant women offered serum screening for Down Syndrome completed a questionnaire assessing theory of planned behaviour constructs: attitude towards undergoing the test, subjective norms of others, perceived behavioural control and intention to undergo the test. Intention predicted screening uptake in both screening settings, but more strongly when screening was part of a routine visit. Perceived behavioural control was not predictive of uptake, and only weakly predictive of intention in both settings. Subjective norm predicted intention more strongly when it referred to partner and friends than when it referred to health professionals, in both settings. Attitude was more strongly predictive of intention to attend screening when screening was organised as a part of routine screening, rather than requiring a separate visit. These results suggest that offering a screening test at a routine visit compared with a separate visit is more likely to facilitated uninformed choices, given the stronger association between attitudes and intention and the absence of an association with the perceived influence of health professionals.