Association of pollution and climate with atopic eczema in US children.

BACKGROUND

We sought to determine the relationship between childhood eczema, climate, and environmental pollutants.

METHODS

We analyzed data from the 2007-2008 National Survey of Children's Health including a representative sample of 91,642 children age 0-17 years and the 2006-2007 Environmental Protection Agency measurements of carbon monoxide (CO), nitrate (NO3 ), nitrogen dioxide (NO2 ), organic carbon (OC), sulfate (SO3 ), sulfur dioxide (SO2 ), particulate matter ≤2.5 μm (PM-2.5) and <10 μm (PM-10), and tropospheric ozone levels, and the National Climate Data Center measurements of relative humidity (%), issued UV index, outdoor air temperature, and precipitation levels.

RESULTS

In multivariate survey logistic regression models controlling for age, sex, race/ethnicity, household income, US birthplace, and history of moving to a new location, eczema was associated with higher mean annual NO2 (p = 0.008), SO2 (p = 0.006), SO3 (p = 0.0002), arsenic (p = 0.0007), nickel (p = 0.0002), lead (p = 0.03), vanadium (p < 0.0001), and zinc (p = 0.003), but lower NO3 (p = 0.002), OC (p = 0.03), PM-2.5 (p = 0.006), cadmium (p < 0.0001), copper (p = 0.004), and potassium (p < 0.0001). In contrast, moderate-severe eczema was associated with higher NO3 (p = 0.03), OC (p = 0.008) and PM-2.5 (p = 0.01), copper (p = 0.04), lead (p = 0.008), and zinc (p = 0.01), but lower CO (p = 0.03). Principal component analysis was used and identified 4 combinations of pollutants and climate factors occurring in the USA, of which 1 was associated with higher prevalence and two were associated with lower prevalences of eczema (p < 0.05).

CONCLUSIONS

Pollutants in conjunction with climate factors may differentially impact eczema prevalence and severity, some with apparent harmful effects.