Factors associated with participation in colorectal cancer screening in Australia: Results from the 45 and Up Study cohort

The Australian Government's National Bowel Cancer Screening Program (NBCSP) was introduced in 2006 to provide free home-based immunochemical faecal occult blood test (iFOBT) to eligible Australians turning 55 and 65 years in that year. With the gradual inclusion of additional age cohorts, the rollout of the NBCSP is being implemented in the context of a degree of opportunistic or de facto screening. This study investigated factors associated with self-reported ever-uptake of the NBCSP and of any CRC screening using follow-up questionnaire data from 105,897 Australians aged ≥ 45 years enrolled in the 45 and Up Study in New South Wales, Australia. Of the 91,968 study participants with information on CRC screening behaviour, 70,444 (76.6%) reported ever-uptake of any CRC screening. 63,777 study participants were eligible for a NBCSP invitation, of these 33,148 (52.0%) reported ever-uptake of screening through the NBCSP. Current smoking (RR = 0.86, 0.83–0.90), non-participation in breast cancer screening (female) or PSA testing (male) (RR = 0.84, 0.81–0.86), poor self-reported health (RR = 0.89, 0.86–0.91), lower levels of education (RR = 0.91, 0.90–0.93), and not speaking English at home (RR = 0.88, 0.85–0.91) were associated with reduced ever-uptake of screening within the NBCSP and of any CRC screening. Individuals with a family history of CRC were less likely to screen through the NBCSP (RR = 0.71, 0.69–0.73), but more likely to participate in any CRC screening (RR = 1.18, 1.17–1.19). Smokers, disadvantaged groups and those with non-English speaking backgrounds are less likely to have ever-participated in organised screening through the NBCSP or in any form of CRC screening, supporting efforts to improve participation in these groups.