Climatic Factors Are Associated with Childhood Eczema Prevalence in the United States

Abstract

Atopic dermatitis (AD, atopic eczema) is driven by a complex relationship between genetic predisposition and environmental exposures. We sought to determine the impact of specific climatic factors on the US prevalence of AD. We used a merged analysis of the 2007 National Survey of Children's Health from a representative sample of 91,642 children age 0–17 years and the 2006–2007 National Climate Data Center and Weather Service measurements of relative humidity (%), indoor heating degree days (HDD), clear sky UV indices ozone levels, and outdoor air temperature. As a proxy for AD, we used an affirmative response to the NSCH survey question asking whether the participant’s child has been given a doctor diagnosis of “eczema or any other kind of skin allergy” in the previous 12 months. In multivariate models controlling for sex, race/ethnicity, age and household income, eczema prevalence was significantly lower with highest-quartile mean annual relative humidity (logistic regression, adjusted odds ratio [95% confidence interval]=0.82 [0.71–0.96], P=0.01) and issued UV index (0.73 [0.64–0.84], P<0.0001), and with two other factors associated with increased UV exposure. Eczema prevalence was decreased with highest-quartile air temperature (0.80 [0.70–0.92], P=0.002), but increased with 3rd–quartile mean annual HDD (1.26 [1.11–1.43], P=0.0003). This study provides evidence of climate influences on the US prevalence of childhood eczema.

Prevalence of Atopic Dermatitis in Korean Children Based on Data From the 2008-2011 Korean National Health and Nutrition Examination Survey

“…26 Indeed, previous reports have shown that AD symptoms correlate positively with latitude and negatively with annular outdoor temperature. 27 These data may also suggest that females are susceptible to environmental factors with respect to AD. Our data also revealed a significant geographic variability in disease prevalence in Korea with a higher prevalence in lower latitude cities and province.…”

Environmental risk factors and their role in the management of atopic dermatitis

“…Indoor relative humidity is inversely associated with eczema prevalence, i.e. higher indoor humidity is associated with lower rates of AD [84,90]. However, conflicting results have been found about whether outdoor humidity is positively or inversely associated with AD prevalence [85,87,88,90].…”

“…higher indoor humidity is associated with lower rates of AD [84,90]. However, conflicting results have been found about whether outdoor humidity is positively or inversely associated with AD prevalence [85,87,88,90]. Further epidemiological research on humidity and AD is warranted, particularly because humidifiers are commonly used as an adjunctive treatment by AD patients.…”

“…Moreover, a study of the ISAAC Phase III survey in Spain found a negative association between outdoor temperature and AD prevalence [85]. Likewise, Silverberg et al found a lower prevalence of AD in US states with higher quartile temperature [90]. One study that looked at multiple meteorological variables and symptom severity in eczema found that rising air temperature was actually associated with decreased pruritus, but it must be noted that the temperature change was from very cold (−17° C) to moderate (+18°C) [86].…”

“…People living in warmer climates use less indoor heating, which may trigger or aggravate AD [90]. Moreover, people living in warmer climates may spend more time outdoors and consequently have more UV exposure, which may protect against AD [90].…”