Racial differences in susceptibility to infection by Mycobacterium tuberculosis.
N Engl J Med
; 322(7): 422-7, 1990 Feb 15.
Article
em En
| MEDLINE
| ID: mdl-2300105
ABSTRACT
The prevalence of tuberculosis among blacks is known to be about twice that among whites. When we looked at infection rates among the initially tuberculin-negative residents of 165 racially integrated nursing homes in Arkansas, we were stimulated to investigate whether this difference could be due in part to racial differences in susceptibility to Mycobacterium tuberculosis infection. A new infection was defined by an increase of greater than or equal to 12 mm of induration after a tuberculin skin test (5 tuberculin units) administered at least 60 days after a negative two-step test. On repeat skin testing of the 25,398 initially tuberculin-negative nursing home residents, we found that 13.8 percent of the blacks and only 7.2 percent of the whites had evidence of a new infection (relative risk, 1.9; 95 percent confidence interval, 1.7 to 2.1). Blacks were infected more frequently, regardless of the race of the source patient. In homes with a single source patient who was white, 17.4 percent of the black and 11.7 percent of the white residents became infected (relative risk, 1.5; 95 percent confidence interval, 1.2 to 1.9); in homes with a single source patient who was black, 12.4 percent of the black and 7.7 percent of the white residents became infected (relative risk, 1.6; 95 percent confidence interval, 1.2 to 2.1). However, there was no racial difference in the percentage of residents who had recently converted to positive status who, in the absence of preventive therapy, were later found to have clinical tuberculosis (blacks, 11.5 percent; whites, 10.6 percent). Data from three outbreaks of tuberculosis in two prisons also showed that blacks have about twice the relative risk of whites of becoming infected with M. tuberculosis. We conclude that blacks are more readily infected by M. tuberculosis than are whites. The data also suggest that susceptibility to M. tuberculosis infection varies independently of the factors governing the progression to clinical disease.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Tuberculose
/
População Negra
Tipo de estudo:
Etiology_studies
/
Observational_studies
/
Prevalence_studies
/
Risk_factors_studies
Limite:
Adult
/
Aged
/
Female
/
Humans
/
Male
País/Região como assunto:
America do norte
Idioma:
En
Revista:
N Engl J Med
Ano de publicação:
1990
Tipo de documento:
Article