Statistical Analyses
Bivariate analyses were performed using Fisher’s exact test or t-tests as appropriate. Multivariable analyses were then performed using logistic regression to evaluate the association between PCP-diagnosed asthma and API status, adjusting for variables that had p-value<0.10 in the bivariate analysis plus a priorifactors including gender, C-section, and tobacco exposure. Potential confounders (p-value<0.10) included maternal BMI, education, and oral contraceptive use; birthweight; placenta weight; pets at home at 6 months; age at daycare start; gastroesophageal reflux disease (GERD) by 12 months; acute otitis media (AOM) by 18 months; bronchiolitis, croup, or pneumonia prior to PCP asthma diagnosis; and cord blood 25(OH)D, CC16, adiponectin, and IL12p40. These were retained in the final model if their coefficients were significant, or they contributed significantly to the best model fit. Ap -value<0.05 was considered statistically significant. SPSS® v17.0 (IBM, Armonk, NY) was used throughout.