The incidence rate of familial adenomatous polyposis - Results from the Danish polyposis register

Based on the Danish Polyposis Register epidemiological calculations on familial adenomatous polyposis (FAP) were carried out. The mean annual incidence was 1.85x10(-6) during the years 1971-1992, and the prevalence increasing to about 32x10(-6) at the end of 1992. FAP patients constituted a decreased percentage of all Danish patients with colorectal cancer (0.07% in 1980-1992). The completeness of registration was 97% in 1983 - 1992. The results are similar to Finnish estimates based on the same direct method of calculation, and as both series are based on almost complete national polyposis registration in well-registered populations we regard our results to be close to the true incidence rate.