Incidence of aplastic anemia in a defined subpopulation from Mexico City.

Aplastic anemia (AA) is a hematological disease characterized by the deficient production of blood cells. The incidence of AA worldwide is low (1-5 new cases per 10(6) individuals per year). In contrast to other countries, no current reports exist on the incidence of this disorder in Mexico. In the present study, we have determined the incidence of AA in a defined subpopulation from Mexico City during the period 1996-2000. For the purpose of this study, we focused on the experience from a single medical institution: the Mexican Institute of Social Security (IMSS), which covers around 50% of Mexico's population. The incidence of AA was determined based on the actual number of patients diagnosed with this disease at the IMSS in Mexico City in a given year and the total number of individuals registered at the IMSS in Mexico City in the same year. Considering the IMSS population as a whole, the annual incidence of AA was 3.9 new cases per 10(6) individuals per year. In the pediatric population, the annual incidence was 4.2 new cases per 10(6) individuals per year, whereas in people 15-years-old and older the incidence was 3.8 new cases per 10(6) individuals per year. These incidences were higher than those reported in most studies from the USA, Europe and Israel. Compared to the incidence in Thailand, the incidence we observed in children was considerably higher, whereas the one in adults was similar to the one in that country. The results of the present study suggest that the incidence of AA in Mexico City is one of the highest worldwide, particularly in terms of the pediatric population; however, these results must be taken with caution since this study comprises only a subpopulation from Mexico City and not the entire population. Thus, further studies including a broader population, both in Mexico City and other urban and rural areas of this country, will be necessary in order to obtain better and more complete estimates of the actual incidence of AA in Mexico.