Cool, Dry Weather Boosts Eczema Risk

RALEIGH, N.C. – Climate and weather can be added to the short list of factors known to influence the prevalence of atopic dermatitis, according to Dr. Jonathan I. Silverberg.

He presented a first-of-its-kind analysis in which he merged data from the Department of Health and Human Services’ 2007 National Survey of Children’s Health with state-by-state data from the National Oceanic and Atmospheric Administration’s National Climatic Data Center and the National Weather Service.

The National Survey of Children’s Health involved in-depth telephone interviews with parents in 91,642 households having one or more children under age 18 years.

Among the key findings: The prevalence of eczema was significantly lower in areas of the country with high relative humidity during the previous 2 years, especially during the months of November through April. The prevalence of eczema was also lower in areas with a high-to-extreme UV index, and with a higher-than-average outdoor air temperature, noted Dr. Silverberg of St. Luke’s–Roosevelt Hospital Center, New York.

In contrast, eczema prevalence was increased in regions with a high heating degree day index, which is a statewide, population-based measure of the energy demand needed to heat indoor structures by 1° F for 1 day using a baseline temperature of 65° F.

Children living in areas in the top tertile nationally in terms of mean relative humidity had a 20% lower risk of having eczema than did those residing in the lowest tertile. Children living in the top tertile for mean annual outdoor air temperature had a 23% lower prevalence of eczema than did those in the lowest tertile. Similarly, children living in areas with a high-to-extreme UV index, a measure which incorporates clear-sky days, had a 24% lower eczema prevalence than did children living under the condition of a low-to-moderate UV index.

Children residing in regions in the top tertile in terms of heating degree days had a 30% higher prevalence of eczema than did those living in the lowest tertile.

The most likely explanation for the effects climactic factors exert upon eczema prevalence involves the environmental impact upon skin barrier function. However, this study can’t pinpoint causality. Other possible mechanisms that might account for the observed association include vitamin D status, immune responses, or allergen exposures, according to Dr. Silverberg.

Previously established risk factors for eczema include family history, race/ethnicity, urban living, and socioeconomic status.

This study was funded in part by a grant from the National Institute of Arthritis and Musculoskeletal and Skin Diseases. Dr. Silverberg reported having no financial conflicts.

RALEIGH, N.C. – Climate and weather can be added to the short list of factors known to influence the prevalence of atopic dermatitis, according to Dr. Jonathan I. Silverberg.

He presented a first-of-its-kind analysis in which he merged data from the Department of Health and Human Services’ 2007 National Survey of Children’s Health with state-by-state data from the National Oceanic and Atmospheric Administration’s National Climatic Data Center and the National Weather Service.

The National Survey of Children’s Health involved in-depth telephone interviews with parents in 91,642 households having one or more children under age 18 years.

Among the key findings: The prevalence of eczema was significantly lower in areas of the country with high relative humidity during the previous 2 years, especially during the months of November through April. The prevalence of eczema was also lower in areas with a high-to-extreme UV index, and with a higher-than-average outdoor air temperature, noted Dr. Silverberg of St. Luke’s–Roosevelt Hospital Center, New York.

In contrast, eczema prevalence was increased in regions with a high heating degree day index, which is a statewide, population-based measure of the energy demand needed to heat indoor structures by 1° F for 1 day using a baseline temperature of 65° F.

Children living in areas in the top tertile nationally in terms of mean relative humidity had a 20% lower risk of having eczema than did those residing in the lowest tertile. Children living in the top tertile for mean annual outdoor air temperature had a 23% lower prevalence of eczema than did those in the lowest tertile. Similarly, children living in areas with a high-to-extreme UV index, a measure which incorporates clear-sky days, had a 24% lower eczema prevalence than did children living under the condition of a low-to-moderate UV index.

Children residing in regions in the top tertile in terms of heating degree days had a 30% higher prevalence of eczema than did those living in the lowest tertile.

The most likely explanation for the effects climactic factors exert upon eczema prevalence involves the environmental impact upon skin barrier function. However, this study can’t pinpoint causality. Other possible mechanisms that might account for the observed association include vitamin D status, immune responses, or allergen exposures, according to Dr. Silverberg.

Previously established risk factors for eczema include family history, race/ethnicity, urban living, and socioeconomic status.

This study was funded in part by a grant from the National Institute of Arthritis and Musculoskeletal and Skin Diseases. Dr. Silverberg reported having no financial conflicts.

RALEIGH, N.C. – Climate and weather can be added to the short list of factors known to influence the prevalence of atopic dermatitis, according to Dr. Jonathan I. Silverberg.

He presented a first-of-its-kind analysis in which he merged data from the Department of Health and Human Services’ 2007 National Survey of Children’s Health with state-by-state data from the National Oceanic and Atmospheric Administration’s National Climatic Data Center and the National Weather Service.

The National Survey of Children’s Health involved in-depth telephone interviews with parents in 91,642 households having one or more children under age 18 years.

Among the key findings: The prevalence of eczema was significantly lower in areas of the country with high relative humidity during the previous 2 years, especially during the months of November through April. The prevalence of eczema was also lower in areas with a high-to-extreme UV index, and with a higher-than-average outdoor air temperature, noted Dr. Silverberg of St. Luke’s–Roosevelt Hospital Center, New York.

In contrast, eczema prevalence was increased in regions with a high heating degree day index, which is a statewide, population-based measure of the energy demand needed to heat indoor structures by 1° F for 1 day using a baseline temperature of 65° F.

Children living in areas in the top tertile nationally in terms of mean relative humidity had a 20% lower risk of having eczema than did those residing in the lowest tertile. Children living in the top tertile for mean annual outdoor air temperature had a 23% lower prevalence of eczema than did those in the lowest tertile. Similarly, children living in areas with a high-to-extreme UV index, a measure which incorporates clear-sky days, had a 24% lower eczema prevalence than did children living under the condition of a low-to-moderate UV index.

Children residing in regions in the top tertile in terms of heating degree days had a 30% higher prevalence of eczema than did those living in the lowest tertile.

The most likely explanation for the effects climactic factors exert upon eczema prevalence involves the environmental impact upon skin barrier function. However, this study can’t pinpoint causality. Other possible mechanisms that might account for the observed association include vitamin D status, immune responses, or allergen exposures, according to Dr. Silverberg.

Previously established risk factors for eczema include family history, race/ethnicity, urban living, and socioeconomic status.

This study was funded in part by a grant from the National Institute of Arthritis and Musculoskeletal and Skin Diseases. Dr. Silverberg reported having no financial conflicts.