Psychosocial variables associated with colorectal cancer screening in South Australia

Background: Population screening reduces mortality from colorectal cancer, yet factors associated with uptake of screening are incompletely understood. Purpose: The purpose of the study was to determine demographic and psychosocial factors associated with participation in faecal occult blood test (FOBT)-based colorectal cancer (CRC) screening in an average risk community programme in Adelaide, South Australia. Method: A questionnaire consistent with the Preventive Health Model was used to determine demographic and psychosocial differences between previous FOBT-based screening participants (n=413, response rate 93.2%) and non-participants (n=481, response rate 47.9%). Results were analysed by univariate and multivariate generalised linear modelling, and factors associated with participation were identified. Results: Factor analysis of psychosocial items revealed an optimal three-factor solution (knowledge, faecal aversion, belief in the value of screening). Following multivariate analyses, two psychosocial and two demographic factors remained as predictors of FOBT screening behaviour: (1) items related to faecal aversion (Aversion), relative risk (RR)=0.61, CI=0.55-0.69, (2) perceptions about the value of screening (Value), RR=1.45, CI=1.13-1.85, (3) age band 65-69 (Age, five age bands, relative to age 50-54), RR=1.43, CI=1.16-1.76 and FOBT type (Test; three tests, Hemoccult^®, FlexSure^®, InSure ^® randomly assigned, relative to Hemoccult^®: FlexSure^®: RR=1.41, CI=1.17-1.71, InSure^®: RR=1.76, CI=1.47-2.11. Conclusions: The psychosocial factors associated with nonparticipation in FOBT-based CRC screening are amenable to interventions designed to improve participation. The small relative risks values associated with each predictor, however, raise the possibility that additional factors are likely to influence screening participation.