Association of seropositivity for hepatitis viruses and aplastic anemia in Thailand.
Aplastic anemia is more common in the Orient than in western countries, with an incidence in Thailand that is 2- to 3-fold higher than in Europe. Aplastic anemia after hepatitis is a well characterized clinical entity, and clinical hepatitis is also prevalent in the Far East. We performed a prospective case-control study to determine risk factors for aplastic anemia in Bangkok and two rural regions during 1989 to 1994. A total of 375 cases were identified, along with 1,174 hospital controls matched for age and sex. Historical data were collected by trained interviewers. Sera from a subset of cases (N = 177) and controls (N = 183) were tested for antibodies to hepatitis viruses A, B, and C and hepatitis B surface antigen. There was no evidence of association of aplastic anemia with hepatitis B or hepatitis C. Previous exposure to hepatitis A, as determined by immunoglobulin G (IgG) seropositivity, was significantly associated with aplastic anemia: the relative risk adjusted for confounding was 2.9 (95% confidence interval 1.2-6.7). The same association also existed for persons under age 25 years, in whom the prevalence of hepatitis A IgG was lower than in the total population. However, no patients showed evidence of recent infection with hepatitis A (immunoglobulin M [IgM] seropositivity). These results indicate that exposure to a hepatitis virus is a risk indicator for aplastic anemia in Thailand, and while itself unlikely to be etiologic, hepatitis A may be a surrogate marker for another enteric microbial agent.
Issaragrisil
S
S
Department of Medicine, Siriraj Hospital, Mahidol University Bangkok, Thailand.
Kaufman
D
D
Thongput
A
A
Chansung
K
K
Thamprasit
T
T
Piankijagum
A
A
Anderson
T
T
Shapiro
S
S
Leaverton
P
P
Young
N S
NS
D000328:Adult; D000741:Anemia, Aplastic / Q000150:complications* / Q000453:epidemiology; D016022:Case-Control Studies; D006506:Hepatitis A / Q000150:complications* / Q000175:diagnosis / Q000453:epidemiology; D006509:Hepatitis B / Q000150:complications* / Q000175:diagnosis / Q000453:epidemiology; D006526:Hepatitis C / Q000150:complications* / Q000175:diagnosis / Q000453:epidemiology; D006801:Humans; D012698:Serologic Tests; D013785:Thailand / Q000453:epidemiology