Comparison of competitive cognitive models in explanation of women breast cancer screening behaviours using structural equation modelling: Health belief model and theory of reasoned action.

Abstract

The efficacy of the theory of reasoned action (TRA), compared with the health belief model (HBM), has not been fully elucidated in screening practices. This population-based cross-sectional study was conducted with samples of 500 women aged 35-85years, in the north of Iran. The data of demographic characteristics, awareness, health belief, subjective norms and screening behaviours were collected using standard instruments. Structural equation modelling (SEM) was applied to estimate the pathways of regression coefficients. The model that incorporated the health belief and the standardised coefficient of the knowledge scores influenced significantly on the health belief perception (beta=0.375), and consequently, the health belief directly affected screening behaviours (beta=0.73). In contrast, In TRA model, while the direct effect of knowledge on intention was negligible it has a greater indirect effect by mediating health belief and subjective norms (indirect beta=0.35) on behaviour intention. A high coefficient of intention was observed by subjective norms (beta=0.626), and the intention has a great positive effect on screening behaviour (beta=0.601). All fitting indexes were quietly improved in the TRA model as compared with HBM. Thus, the unifying structure of knowledge, health belief, subjective norms and intention improves the predictor power in breast cancer screening behaviours.