Uptake trends in the Scottish Bowel Screening Programme and the influences of age, sex, and deprivation.

Objective: Age, sex, and deprivation are known factors influencing colorectal (bowel) cancer screening uptake. We investigated the influence of these factors on uptake over time. Methods: Data from the Scottish Bowel Screening Programme (SBoSP) were collected between 2007 and 2014. End-points for analysis were uptake, faecal occult blood test positivity, and disease detection, adjusted for age, sex, deprivation, and year of screening. Results: From 5,308,336 individual screening episodes documented, uptake gradually increased with increasing age up to 65-69 and was lower in men than women (52.4% vs. 58.7%, respectively). Deprivation had a significant effect on uptake by men and women of all age groups, with the most deprived least likely to complete a screening test. Uptake has increased with time in both sexes and across the deprivation gradient. The number needed to screen to detect significant neoplasia was significantly lower in men than women overall (170 vs. 365), and this held over all age and deprivation groups. The number needed to screen was also lower in the more deprived population. Conclusions: Although lower age, male sex, and increased deprivation are associated with lower bowel cancer screening uptake in Scotland, uptake has increased since SBoSP introduction in all age groups, both sexes, and across the deprivation gradient. Despite a lower uptake, the number needed to screen to find significant disease was lower in men and in those with higher levels of deprivation.