The epidemiology of infantile hypertrophic pyloric stenosis in a Danish population, 1950-84.

The epidemiology of Infantile Hypertrophic Pyloric stenosis (IHPS) was studied in a geographically well-delineated and demographically representative Danish region (The County of Funen), covering the period 1 January 1950 to 31 December 1984. Based upon 679 cases, the cumulative incidence from birth of IHPS was found to be virtually unchanged during the study period at a level of 4.8 per 1000 liveborn boys and 1.3 per 1000 liveborn girls. In an analysis of clinical and demographic variables, the development of IHPS was found to be associated with low parity status (regardless of maternal age). The preterm cases had a longer interval from birth to onset of symptoms, compared with those born at term. No statistically significant associations were found between IHPS and seasonal variations at onset of symptoms, ABO and Rhesus blood groups, and maternal age.