Epidemiology of acute promyelocytic leukemia.

Background. The estimated incidence of acute promyelocytic leukemia (APL) is approximately 6 cases per 10 million people per year with no apparent differences between sexes. The age of APL cases is younger than that of other acute myeloid leukemias (AML). Spatial and temporal clusters of APL have been reported. These observations suggest a possible selective role for environmental and/or occupational factors in APL development. Methods. A multicenter case-control study was carried out on risk factors for acute leukemias and preleukemias. In this report data related to APL we selectively analyzed from the larger study to identify specific risk factors. Results. The case-control study on 38 cases of APL showed a strong association with shoemaking (odds ratio 6.3, 95% confidence interval 1.3-31.1). A moderate leukemogenic effect from living in houses built with tuff, a porous building material containing γ-emitting radionuclides and having a high radon concentration, and from using hair dyes was also suggested. Conclusions. These data, together with the reported spatial and temporal clustering of APL, support the hypothesis of specific environmental and/or occupational risk factors for APL among other AML subtypes and indicate the need for additional ad hoc multicenter studies.