Traffic pollution is associated with early childhood aeroallergen sensitization.

BACKGROUND: No large, prospective, epidemiologic study has investigated the association between diesel exhaust particle (DEP) exposure and early aeroallergen sensitization and allergic rhinitis (AR) at 4 years of age. OBJECTIVE: To determine how exposure to traffic exhaust during infancy is associated with aeroallergen sensitization and AR at 4 years of age and the predictive utility of the wheal area at 1 to 3 years of age on AR at 4 years of age. METHODS: Infants born to aeroallergen sensitized parents were evaluated annually with skin prick tests to 15 aeroallergens with measurement of wheal areas. At 4 years of age, AR was defined as at least one positive aeroallergen skin prick test result and the presence of sneezing and a runny nose without a cold or flu. Infant (DEP) exposure was estimated using data from 27 air sampling monitors and a land use regression model. RESULTS: Complete data were available for 634 children at 4 years of age. Prevalence of AR increased annually from 6.9% to 21.9%. A positive trend was observed for high DEP exposure and aeroallergen sensitization at 2 and 3 years of age (odds ratio, 1.40; 95% confidence interval, 0.97-2.0) and (odds ratio, 1.35; 95% confidence interval, 0.98-1.85) but not with AR. At 2 years of age, every 1-mm(2) increase in the wheal area of timothy and Alternaria significantly increased the odds of AR at 4 years of age. At 3 years of age, every 1-mm(2) increase in the wheal area of fescue, dog, and Penicillium significantly increased the odds of AR at 4 years of age. CONCLUSION: DEP exposure enhances the risk of early aeroallergen sensitization. Aeroallergen wheal area at 2 and 3 years of age is associated with AR at 4 years of age.

Validating childhood symptoms with physician-diagnosed allergic rhinitis.

BACKGROUND: Multiple population-based and high-risk cohort studies use parental questionnaire responses to define allergic rhinitis (AR) in children. Individual questionnaire items have not been validated by comparison with physician-diagnosed AR (PDAR). OBJECTIVE: To identify routine clinical questions that best agree with a physician diagnosis of AR and can be used for early case identification. METHODS: Children participating in a longitudinal birth cohort study were evaluated at ages 1 through 4 and at age 7 (n = 531) using questionnaires, physical examinations, and skin prick tests (SPT) with 15 aeroallergens (AG). Parents answered 3 stem questions pertaining to their child, including presence of nasal symptoms absent a cold/flu (ISAAC-validated question), presence of hayfever, and ocular itch. Substem questions were answered with details regarding seasonality, nasal triggers, and ocular seasonality. A global assessment of allergic diseases, including AR, was performed by a specialty-trained clinician. Percent agreement, sensitivity, specificity, and positive predictive values were assessed for individual stem and substem questions. RESULTS: Positive response to having hayfever and presence of ocular symptoms had the highest specificity (84% and 69%, respectively) and the highest percent agreement (74% and 68%) with PDAR. Identification of triggers for nasal and ocular symptoms had the highest sensitivity (89%). Positive predictive values ranged from 31 to 39%. Combining 2 responses with highest agreement increased specificity for PDAR to 91%. CONCLUSION: Responses to hayfever and ocular symptoms had better specificity and percent agreement with PDAR than the ISAAC-validated questionnaire item. Combining 2 rhinitis questions sharply increases specificity and may improve diagnostic accuracy of clinical questions.

Unraveling the relationship between aeroallergen sensitization, gender, second-hand smoke exposure, and impaired lung function.

BACKGROUND: Contradictory findings on the differential effects of second-hand smoke (SHS) on lung function in girls and boys may result from masked relationships between host and environmental factors. Allergic sensitization may augment the relationship between SHS and decreased lung function, although its role in relation to the inconsistent gender differences in children has not been elucidated. HYPOTHESIS: We hypothesize that there will be differences between boys and girls related to early-life allergic sensitization and exposure to SHS on pulmonary function later in childhood. METHODS: Participants in this study (n = 486) were drawn from the Cincinnati Childhood Allergy and Air Pollution (CCAAPS) birth cohort study consisting of 46% girls. Allergic sensitization was assessed by skin prick test (SPT) to 15 aeroallergens at ages 2, 4, and 7, while pulmonary function and asthma diagnosis occurred at age 7. SHS exposure was measured by hair cotinine at ages 2 and/or 4. Gender differences of SHS exposure on pulmonary function among children with positive SPTs at ages 2, 4, and 7 as well as first- and higher-order interactions were examined by multiple linear regression. Interactions significant in the multivariate models were also examined via stratification. Comparisons within and between stratified groups were assessed by examining the slope of the parameter estimates/beta coefficients and associated p-values and confidence intervals. RESULTS: Increased cotinine levels were significantly associated with decreases in FEV(1) (-0.03 l, p < 0.05), peak expiratory flow (-0.07 l/s, p < 0.05), and FEF (25-75%) (-0.06 l/s, p < 0.01). The interaction between cotinine and sensitization at age 2 was borderline significant (p = 0.10) in the FEF(25-75%) model and showed an exposure response effect according to the number of positive SPTs at age 2; zero (-0.06 l/s, p < 0.01), one (-0.09 l/s, p < 0.05), or two or more positive SPTs (-0.30 l/s, p < 0.01). Despite increased polysensitization among boys, the association between cotinine and FEF(25-75%) among girls, with two or more positive SPTs at age 2, showed the greatest deficits in FEF(25-75%) (-0.34 l/s vs. -0.05 l/s and -0.06 l/s for non-sensitized girls and boys, respectively. Girls with two or more positive SPTs showed a twofold greater decrease in FEF(25-5%) (-0.34 l/s; 95% CI: -0.55, -0.13) compared to boys with the same degree of allergic sensitization (-0.18 l/s; 95% CI: -0.41, 0.06), although this difference was not statistically significant. CONCLUSIONS: Reductions in lung function were observed among children exposed to SHS, and the number of aeroallergen-positive SPTs at age 2 modifies this relationship. Girls experiencing early childhood allergic sensitization and high SHS exposure are at greater risk of decreased lung function later in childhood compared to non-sensitized girls and boys and demonstrate greater deficits compared to boys with similar degrees of sensitization.