Climate and prevalence of atopic eczema in 6- to 7-year-old school children in Spain. ISAAC PhASE III

Abstract

Atopic eczema (AE) is a chronic skin disease. Recent reports indicate that the worldwide prevalence of AE is increasing and that various environmental factors are implicated in its aetiology. Climatic conditions have been related with AE prevalence, and Spain has varying climatic conditions. The aim of this study is to document the possible climatic influence on the prevalence of AE in schoolchildren aged 6-7 years in three different climatic regions in Spain. We conducted a cross-sectional population-based survey of 28,394 schoolchildren aged 6-7 years from 10 Spanish centres in three different climatic regions. The mean participation rate was 76.5%. AE prevalence was assessed using the International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire and the Spanish Academy of Dermatology criteria used in Spain to diagnose AE. The data, including annual temperature, precipitation, relative humidity and the annual number of sunny hours per climatic region, were obtained from the Spanish National Institute of Meteorology. Different AE prevalences were found in all three climatic regions studied: Atlantic, 32.9; Mediterranean 28.3; and Continental 31.2 per 100 children studied (p < 0.005). AE was positively associated with precipitation and humidity, and was negatively associated with temperature and the number of sunny hours. The results show that AE is significantly dependent on meteorological conditions.

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

“…A 2004 epidemiological study demonstrated reduced childhood AD with higher mean annual outdoor temperature in Europe [84]. 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].…”

“…Yet, until recently, there was little evidence to support this notion. One study found that relocating children with AD from the home subarctic/temperate climate of Norway to a subtropical climate in Gran Canary for 4 weeks improved skin symptoms and quality of life [3,[83][84][85][86][87][88]. The climate in a given geographic location is determined by a combination of multiple factors, including temperature, humidity, and precipitation, as well as related factors, such as ultraviolet (UV) exposure.…”

“…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.…”

Assessment of dietary food and nutrient intake and bone density in children with eczema

“…3,22 Milk intake was also negatively associated with eczema diagnosis among Spanish primary schoolchildren. 23 Dietary intake of vitamin D was very low in our children, and virtually all (both cases and controls) ingested a lower amount than the age-and sexspecific dietary reference intake for the Chinese population (Table 4). Our data also suggested an inverse relationship between eczema severity and vitamin D intake.…”

La Dermatitis Atópica en Quito y el Ecuador.

“…En la variable climática se ha encontrado relación de asociación positiva con la latitud y negativa con la temperatura media exterior en países alejados del trópico como se ha corroborado en estudios realizados en Taiwan y España (12,13 Finlandia en el grupo de adolescentes, las frecuencias más altas de eccema se encuentran en los países que se ubican entre los trópicos de Cáncer y de Capricornio (Tablas 4 y 5) Es los países ubicados en estas zonas tropicales, como el Ecuador, los cambios de hábitos de vestido por la variación térmica, el grado de humedad ambiental (muy bajo en Quito), el estado de hidratación de la piel, la polución medioambiental, la mayor exposición a la radiación ultravioleta (¿de los trópi-cos? ), pueden favorecer sensibilizaciones mediadas por IgE (14)(15)(16).…”