The opinion is prevalent among students of hypertrophic pyloric stenosis that the incidence of the disorder differs widely in different countries. It is generally maintained that it is common among Anglo-Saxons but relatively rare in the Latin races. The disease does not seem to occur at all or, at least, is extremely rare in certain races. Eckstein1 reported that he observed only 2 children with pyloric stenosis among 50,000 patients in the outpatient department for children's diseases at Ankara, the capital of Turkey, and the parents of these 2 patients were foreigners. Vilén,2 a pediatrically trained medical missionary mentioned that during his many years' service in the Belgian Congo he encountered only 1 patient with pyloric stenosis, a child of French parentage.
The opinion that the disease is common in one country and rare in another is to a great extent based on the number of reports published
WALLGREN A. INCIDENCE OF HYPERTROPHIC PYLORIC STENOSIS. Am J Dis Child. 1941;62(4):751-756. doi:10.1001/archpedi.1941.02000160052006