2.3 | Statistical analysis
To investigate whether exposure to ambient PM affects the remission of AD in young children, we evaluated the associations of long-term exposure (from birth to age 3) to ambient PM10 with the persistence of AD and the incidences of allergen sensitizations at age 3 using Cox proportional hazard regression models. Ambient nitric dioxide (NO2), sulfur dioxide (SO2), ozone (O3), carbon monoxide (CO), relative humidity (RH), and temperature, sex, BMI, SCORAD at enrollment, and the presence of inhalant allergen sensitization were included in the Cox models as confounding factors.
All procedures were conducted using R version 4.0.2 (Comprehensive R Archive Network: http://cran.r-project.org). The “survival” package (version 3.1-12) was used for Cox proportional hazard regression model fitting. All tests were two-sided, and an alpha level of less than 0.05 was considered significant.