5568 colonoscopic procedures were recorded: 3185 in the gFOBT cohort in people aged 50 to 74 (men 54.7%) and 2383 in the AI cohort (mean age 58.9 y, men 48.1%). Overall, the advanced neoplasia rate was 31.0% in the gFOBT cohort and 12.5% in the AI cohort (p < 0.0001). In the latter, indications were symptoms (56.5%), screening (23.5%) and surveillance (20.0%). In the AI cohort, 1099 people (50.4%) had never had any previous colorectal examination. In this group, advanced neoplasia rates were not significantly different between people explored for symptoms (11.4%) and screening (10.6%). In the symptomatic group, abdominal pain and change in bowel habits had the lowest advanced neoplasia rate (6.0%). In the screening group, the advanced neoplasia rate was not significantly different between people with a family history of CRC, even in a first-degree relative < 60 y (9.2%) and without (19.4%). In both cohorts, the advanced neoplasia rate increased with age and was 1.9 time higher in men than in women. In the previously unexplored group of the AI cohort, the advanced neoplasia rate was low in women, similar in the 40-49 y and 50-59 y age groups (3.8% and 3.9%) and increased to 10.1% in the 60-69 y age group. It was respectively 8.5% and 21.3% in men in the 40-49 y and 50-59 y age groups. In the 40-59 y age group, men were four times as likely to have advanced neoplasia compared with women.