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

Sunny hours and variations in the prevalence of asthma in schoolchildren according to the International Study of Asthma and Allergies (ISAAC) Phase III in Spain

The objective of this study was to estimate the relationship between the prevalence of asthma in schoolchildren aged 6-7 years and 13-14 years and the mean annual sunny hours (MASH) in Spain, and to explore predictive models for asthma prevalence. The prevalence of asthma was obtained from the International Study of Asthma and Allergies (ISAAC) Phase III 2002-2003, and climate and socio-economic variables from official sources. Nine centres were studied and a further four centres, two of which are in ISAAC, to test the predictive models. Logistic regression was used to estimate adjusted prevalence rates of asthma for each centre, and multiple regression models to study the effects of MASH and other meteorological and socio-economic variables. The adjusted prevalence rate of asthma decreased 0.6% [95% confidence interval (CI) 0.4-0.8%] for the 6-7 years group and 1.1% (95% CI 0.8-1.3%) for the 13-14 years group with an increase in the MASH of 100 h. Relative humidity was negatively associated with asthma in the older age group, and gross province product per capita (GPP) was positively associated with asthma in the younger age group. The predictive models, which included MASH, gender, relative humidity, and GPP, anticipated prevalence rates of asthma without significant differences between the levels observed and those expected in 9 of the 11 measurements carried out. The results indicate that sunny hours have a protective effect on the prevalence of asthma in schoolchildren.

Proportional Venn diagram and determinants of allergic respiratory diseases in Italian adolescents

Large variations in prevalence of atopy and allergic diseases are reported worldwide in children, but in epidemiological studies the use of skin prick tests (SPT) and spirometry along with questionnaires is not common in the Mediterranean Area. The present work was aimed at evaluating the prevalence of current asthma (CA), rhinoconjunctivitis (RC), and eczema (E), with atopy and respiratory function, and the role of risk factors for allergic respiratory diseases. A total of 2150 Italian schoolchildren were cross-sectionally investigated through respiratory questionnaire, SPT, and spirometry. A proportional Venn diagram quantified the distribution of CA, RC, and E, stratifying for allergic sensitization to show differences in prevalence of allergic diseases among subjects with and without positive SPT. CA prevalence was 4.2%, RC 17.9%, and E 5.3%. CA and RC increased, while E decreased, with respect to previous local studies. Allergic sensitization prevalence (evaluated as positive response to at least one SPT) was 39.2%. A double Venn diagram identified 15 categories. Atopic CA was threefold more frequent than non-atopic CA. Atopic vs non-atopic RC and E were 9.6% vs 10.3% and 2.0% vs 3.3%, respectively. Atopic vs non-atopic RC associated with CA were 1.6% vs 0.5%; the same figures for RC associated with E were 0.8% vs 1.3%. Asymptomatic atopic subjects were 27.0%. Atopy, RC, parental asthma, and environmental risk factors were associated with CA. Atopy and environmental factors were risk factors also for RC. Asthma and traffic exposure were linked to reduced lung function. Respiratory allergic diseases are still increasing and largely concomitant in Italian adolescents. Atopy is more important for CA than RC. Avoiding exposures to measured environmental risk factors would prevent 41% of current asthma and 34% of rhinoconjunctivitis.

Aeroallergens, allergic disease, and climate change: impacts and adaptation

Recent research has shown that there are many effects of climate change on aeroallergens and thus allergic diseases in humans. Increased atmospheric carbon dioxide concentration acts as a fertilizer for plant growth. The fertilizing effects of carbon dioxide, as well as increased temperatures from climate change, increase pollen production and the allergen content of pollen grains. In addition, higher temperatures are changing the timing and duration of the pollen season. As regional climates change, plants can move into new areas and changes in atmospheric circulation can blow pollen- and spore-containing dust to new areas, thus introducing people to allergens to which they have not been exposed previously. Climate change also influences the concentrations of airborne pollutants, which alone, and in conjunction with aeroallergens, can exacerbate asthma or other respiratory illnesses. The few epidemiological analyses of meteorological factors, aeroallergens, and allergic diseases demonstrate the pathways through which climate can exert its influence on aeroallergens and allergic diseases. In addition to the need for more research, there is the imperative to take preventive and adaptive actions to address the onset and exacerbation of allergic diseases associated with climate variability and change.