Relationship between in utero C-reactive protein levels and asthma in at-risk children

Background Asthma research has focused on postnatal exposures, but there is recent evidence to indicate atopic immune responses might be initiated in utero. Systemic inflammation during pregnancy might indicate an environment that could increase propensity in the child to develop allergic disease. Objective To investigate the association of systemic inflammation, as measured by C-reactive protein (CRP) levels, with asthma and wheezing in offspring within an at-risk, mostly Mexican, cohort. Methods Using data from a randomized education intervention of families at risk for asthma from 1998 followed through 2009 in urban Chicago, asthma was defined as ever having a physician diagnosis of asthma by 3 years of age and wheezing before the third year. Logistic regression models controlling for confounders investigated the effect of prenatal CRP levels on these outcomes. Results There were 244 mother-child pairs included in the study analysis with median prenatal CRP levels of 4.9 mg/L (interquartile range 3.2-7.7). Continuous prenatal CRP levels were predictive of asthma by year 3 (relative risk 2.4, 95% confidence interval 1.3, 3.6) and wheezing in year 3 (relative risk 1.7, 95% confidence interval 1.1, 2.4) after adjustment. Associations remained significant in mothers who were of Mexican ethnicity and were nonsmokers, suggesting that effects might be stronger in children at lower risk of disease. Conclusion Prenatal CRP levels are associated with asthma by year 3 and wheezing in year 3 within a high-risk, urban, mostly Mexican, cohort. Maternal systemic inflammation might reflect a prenatal environment that could increase offspring susceptibility to develop wheezing and asthma young in life.