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Background
Sensitization to cockroach is one of the strongest identified risk factors for greater asthma morbidity in low-income urban communities; however, the timing of exposures relevant to the development of sensitization has not been elucidated fully. Furthermore, exposure to combustion byproducts, including polycyclic aromatic hydrocarbons (PAHs), can augment the development of allergic sensitization.
Objective
We sought to test the hypotheses that domestic cockroach allergen measured prenatally would predict cockroach sensitization in early childhood and that this association would be greater for children exposed to higher PAH concentrations.
Methods
Dominican and African American pregnant women living in New York City were enrolled. In the third trimester expectant mothers wore personal air samplers for measurement of 8 nonvolatile PAHs and the semivolatile PAH pyrene, and dust was collected from homes for allergen measurement. Glutathione-S-transferase ¦Ì 1 (GSTM1) gene polymorphisms were measured in children. Allergen-specific IgE levels were measured from the children at ages 2, 3, 5, and 7 years.
Results
Bla g 2 in prenatal kitchen dust predicted cockroach sensitization at the ages of 5 to 7 years (adjusted relative risk [RR], 1.15; P?= .001; n?= 349). The association was observed only among children with greater than (RR, 1.22; P?= .001) but not less than (RR, 1.07; P?= .24) the median sum of 8 nonvolatile PAH levels. The association was most pronounced among children with higher PAH levels and null for the GSTM1 gene (RR, 1.54; P?= .001).
Conclusions
Prenatal exposure to cockroach allergen was associated with a greater risk of allergic sensitization. This risk was increased by exposure to nonvolatile PAHs, with children null for the GSTM1 mutation particularly vulnerable.
