Infantile hypertrophic pyloric stenosis - Decreasing incidence

Introduction: The study aimed to prove or disprove a clinical suspicion of a decreasing frequency of pyloric stenosis. Method: Retrospective review of hospital records of all children operated f or pyloric stenosis in the hospitals of the County of Viborg from 1 January 1973 to 31 December 1997. This regional review was supplemented by a natio n wide study, in which the National Registry of Patients was searched for t he diagnosis number and the operation code of pyloric stenosis during the p eriod 1 January 1977 to 31 December 1997. Results: One hundred and forty-seven children were operated for infantile h ypertrophic pyloric stenosis in Viborg County during the period in question . When calculated in five-year periods, the respective numbers per 1000 liv eborn children were: 1.6, 2.4, 2.0, 2.8, and 0.9. Only one child was operat ed per year during 1996 and 1997, compared with an average of seven childre n annually during the preceding 20 years. The same tendency was found in th e nationwide study. Until 1993 an average of 160 children were operated per year, i.e. 2.2 to 3.2 per 1000 livebom children. From 1993-1997 inclusive the number decreased to 1.4. In 1996 and 1997, respectively, 75 and 76 chil dren were operated, i.e. 1.1 per 1000 liveborn children. Conclusion: There has been a significant decrease in the incidence of child ren with infantile hypertrophic pyloric stenosis, both in the County of Vib org and in the whole of Denmark. The decrease, which started in 1993, has f or unknown reasons continued to accelerate ever since. The decrease coincid es with changing recommendations concerning the positioning of infants duri ng sleep, but a causal connection is uncertain.