Towards a true prevalence of peptic ulcer: the Sorreisa gastrointestinal disorder study. This study, designed to overcome methodological problems inherent in earlier prevalence studies of peptic ulcer, was carried out in a municipality in northern Norway. It included the total population of 2027, aged 20-69 years, and comprised a questionnaire and search for previously diagnosed peptic ulcers in the local medical records for all subjects, and additional endoscopy of all subjects with dyspepsia and their matched healthy controls (n = 619). The overall prevalence was 10.5% in men and 9.5% in women, a sex ratio close to one and a higher duodenal:gastric ratio than previously reported from this region. A substantial 1% prevalence of asymptomatic ulcers was also observed. 