Environmental factors associated with childhood asthma in Puerto Ricans

Public Health Significance: Asthma is a major public health problem and the most common chronic disease of childhood in the United States. The burden of disease is unequally shared with Puerto Ricans having the highest prevalence, morbidity and mortality from asthma. Asthma is estimated to cost $56 billion dollars annually in the United States due to cost of treatment, hospitalization and absenteeism from work and school. Better understanding the role of risk factors and potential interventions will be critical in addressing this public health disparity. \ud Rationale: Asthma is a multifactorial disease. Understanding the factors contributing to disparities in disease prevalence among Puerto Ricans will provide potential avenues for intervention or prevention. We will accomplish this by examining risk factors including maternal depression, maternal asthma, socioeconomic status and indoor allergen exposure. While maternal depression symptoms and maternal asthma have been separately associated with childhood asthma, no study has estimated their joint effects on asthma in children. Similarly no study has examined the cytokine changes associated with socioeconomic status and whether exposure to cockroach allergen plays a role in that relationship.\ud Objective: To examine whether maternal depressive symptoms and maternal asthma interact on or have joint effects on childhood asthma. Separately, cytokine profiles as related to socioeconomic status and cockroach allergen exposure will be examined. \ud Methods: Cross-sectional study of 655 children (ages 6-14 years) with (n=341) and without (n=314) asthma in San Juan (Puerto Rico). \ud Measurements: Maternal depressive symptoms were assessed using the Center for Epidemiologic Studies Depression (CESD) Scale questionnaire. A CESD score ≥21 points among the Puerto Rican cohort was used to define significant depressive symptoms. A maternal history of asthma was defined as the child’s mother ever having asthma. Asthma in participating children was defined as physician-diagnosed asthma and current wheeze. Cytokine levels were measured using a commercially available TH17 cytokine panel. Cockroach and dust mite allergens were measured using a monoclonal antibody assay. Logistic regression was used for the multivariable analysis. \ud Main Results: In a multivariable analysis, children whose mothers had both history of asthma and depressive symptoms had 6.5 times higher odds of asthma (95% confidence interval for the odds ratio=3.3 to 13.0, P <.0001) than children whose mothers had neither history of asthma nor depressive symptoms. In cytokine analysis cockroach allergen (Blatella germanica, Bla g 2) was associated with a mix of TH2 and TH17 related cytokines. Lower socioeconomic status demonstrated a similar profile being associated with increased IL-4, IL-10, IL-17F, IL-25, IL-31 and TNFα as well as decreased IL-17A. After correction for cockroach allergen (Bla g 2), only increased IL-10 and decreased IL-17A remained significant suggesting that cockroach allergen may have been contributing to previously noted cytokine changes. \ud Conclusions: Findings suggest maternal depressive symptoms and maternal history of asthma have strong joint effects on increasing asthma risk among Puerto Rican children. Cockroach allergen may contribute to TH2 and TH17 related cytokine changes potentially accounting for some of the observed cytokine changes note among lower socioeconomic status