title: The epidemiology of aplastic anemia in Thailand.
abstract: Aplastic anemia has been linked to environmental exposures, from chemicals and medical drugs to infectious agents. The disease occurs more frequently in Asia than in the West, with incidence rates 2- to 3-fold higher. We report updated results of an epidemiologic study conducted in Thailand from 1989 to 2002, in which 541 patients and 2261 controls were enrolled. Exposures were determined by in-person interview. We observed significantly elevated relative risk estimates for benzene (3.5) and other solvents (2.0) and for sulfonamides (5.6), thiazides (3.8), and mebendazole (3.0). Chloramphenicol use was infrequent, and no significant association was observed. Agricultural pesticides were implicated in Khonkaen (northeastern Thailand). There were significant associations with organophosphates (2.1), DDT (6.7), and carbamates (7.4). We found significant risks for farmers exposed to ducks and geese (3.7) and a borderline association with animal fertilizer (2.1). There was a significant association in Khonkaen with drinking other than bottled or distilled water (2.8). Nonmedical needle exposure was associated in Bangkok and Khonkaen combined (3.8). Most striking was the large etiologic fraction in a rural region accounted for by animal exposures and drinking of water from sources such as wells, rural taps, and rainwater, consistent with an infectious etiology for many cases of aplastic anemia in Thailand.
authors.affiliation: Division of Hematology, Department of Medicine, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand. sisis@mahidol.ac.th
authors.forename: Surapol
authors.initials: S
authors.lastname: Issaragrisil
authors.forename: David W
authors.initials: DW
authors.lastname: Kaufman
authors.forename: Theresa
authors.initials: T
authors.lastname: Anderson
authors.forename: Kanchana
authors.initials: K
authors.lastname: Chansung
authors.forename: Paul E
authors.initials: PE
authors.lastname: Leaverton
authors.forename: Samuel
authors.initials: S
authors.lastname: Shapiro
authors.forename: Neal S
authors.initials: NS
authors.lastname: Young
mesh_terms: D000741:Anemia, Aplastic / Q000453:epidemiology*; D000818:Animals; D000829:Animals, Domestic; D001208:Asia; D016022:Case-Control Studies; D003710:Demography; D004781:Environmental Exposure; D006801:Humans; D015994:Incidence; D016017:Odds Ratio; D010575:Pesticides; D013785:Thailand / Q000453:epidemiology
chemical_list: D010575:Pesticides