Objective Colorectal cancer (CRC) screening programmes can reduce CRC mortality. However, the implementation of a screening programme may create or exacerbate socioeconomic and ethnic health inequities if participation varies by subgroup. We determined which organised programmes characterise participation inequities by socioeconomic and ethnic subgroups, and assessed the variation in subgroup participation among programmes collecting group-specific data.

Design Employing a literature review and survey among leaders of national or regional screening programmes, this study identified published and unpublished data on participation by socioeconomic status and ethnicity. We assessed programmes offering faecal occult blood tests (FOBT) for screening. Primary outcome was screening participation rate.

Results Across 24 organised FOBT-screening programmes meeting the inclusion criteria, participation rates ranged from 21% to 73%. Most programmes (13/24, 54%) did not collect data on participation by socioeconomic status and ethnicity. Among the 11 programmes with data on participation by socioeconomic status, 90% (28/31 publications) reported lower participation among lower socioeconomic groups. Differences across socioeconomic gradients were moderate (66% vs 71%) to severe (35% vs 61%). Only six programmes reported participation results by ethnicity. Ethnic differences were moderate, though only limited data were available for evaluation.

Conclusions Across organised CRC screening programmes worldwide, variation in participation by socioeconomic status and ethnicity is often not assessed. However, when measured, marked disparities in participation by socioeconomic status have been observed. Limited data were available to assess inequities by ethnicity. To avoid exacerbating health inequities, screening programmes should systematically monitor participation by socioeconomic status and ethnicity, and investigate and address determinants of low participation.