Prevalence of pollinosis in the Basque Country

Epidemiology of asthma exacerbations and their relation with environmental factors in the Basque Country

BACKGROUND

Asthma is a highly prevalent chronic inflammatory disease characterised by reversible airflow obstruction and hyperreactivity and inflammation of the airways. Factors that cause and/or trigger asthma attacks include host-related factors (genetic predisposition, obesity and sex) and environmental factors (allergens, infections, occupational sensitisation, smoking status, pollution and diet).

OBJECTIVE

To describe the epidemiology of asthma exacerbations (AEs) in the Basque Country and to explore its relationship with potentially associated environmental variables. We studied a total of 31,579 emergency department (ED) visits and 28,189 hospitalisations due to asthma. We describe the trends, incidence, seasonality and the influence of age and sex, as well as of exposure to NO2 , CO, PM, O3 , and pollen, temperature, relative humidity and flu status. We calculated the Pearson's R correlation coefficient for the study variables.

RESULTS

The incidence was 486 and 88.9 cases per 100,000 people for ED visits and hospitalisations, respectively. Slightly over half (53.5%) of the ED cases were male, while females represented 62.6% of the hospital admissions. Hospitalisations are tending to decrease in children and increase in over 64-year-olds. Peaks in cases occur at the beginning of autumn in children and in winter in adults. AEs were correlated positively with exposure to NO2 , CO and to the influenza virus and negatively with temperature and exposure to O3 . These relationships vary, however, with age and season.

CONCLUSIONS AND CLINICAL RELEVANCE

Rates of hospitalisation for AEs and trends in these rates over time are different in adults and children with the patterns varying by sex, season and environmental conditions.

Effect of area of residence on patterns of aeroallergen sensitization in atopic patients

BACKGROUND

An association with sensitization to inhaled allergens and allergic rhinitis and asthma has been established. A recent study concluded that the disparity in allergen sensitization might primarily be caused by environmental factors rather than genetic differences. The primary objective was to identify potential differences in sensitization among subjects with the same ethnicity in South India who reside in different environments.

METHODS

Five hundred forty-six patients presenting to a tertiary allergy center with allergic rhinitis and or asthma underwent evaluation using a structured questionnaire, skin-prick testing to common aeroallergens, and spirometry and were categorized according to area of residence.

RESULTS

The most common allergens causing sensitization were house-dust mite (range, 65-70%), trees (range, 52-56%), and cockroaches (range, 39-53%). There was lower risk of sensitization to cockroach allergens for subjects <21 years old living in suburban (odds ratio [OR], 0.32; 95% confidence interval [CI], 0.12-0.81) and rural environments (OR, 0.33; 95% CI, 0.11-0.96) compared with subjects <21 years old living in urban areas. There was higher risk of sensitization to fungi in subjects <21 years old living in suburban areas (OR, 1.51; 95% CI, 0.60-3.77) and rural environments (OR, 2.71; 95% CI, 0.98-7.48) compared with subjects <21 years old living in urban environments.

CONCLUSION

Sensitization patterns are similar in different areas of residence except in younger subjects. Sensitization to fungi was higher in younger subjects from the rural area and cockroach sensitization were higher in younger subjects from urban areas. Sensitization is an important precursor of clinical allergic disease and further studies to unravel the complex gene-environment interactions of aeroallergen sensitization in different environments are needed.

Prevalence of allergy, patterns of allergic sensitization and allergy risk factors in rural and urban children

BACKGROUND

We aimed to compare the prevalence of allergic diseases and sensitization in children living in urban and rural areas and to identify potential risk/protection factors associated with allergy.

METHODS

School children 12-16 years old, from urban community (n = 201) and rural area (n = 203) were recruited. The data obtained by questionnaire were referred to doctors' diagnosis, skin prick tests (SPTs), and serum specific and total IgE assessment.

RESULTS

The prevalence of allergic diseases in urban children was significantly higher as compared with rural children [asthma 16.42%vs 1.97% (P < 0.001) allergic rhinitis 38.81%vs 10.84% (P < 0.001)]. Positive SPTs to at least one allergen was found in 63.7% of urban and 22.7% rural children (P < 0.001). Significantly higher percentage of allergic rural than urban children were monosensitized or sensitized to 2-4 allergens, but almost a fourfold higher percentage of allergic urban children was found to be sensitized to five or more allergens (P < 0.0001). The history of frequent upper respiratory factor (URT) infections, antibiotic therapy, tonsiltectomy/adenoidectomy were positively associated with development of atopy and sensitization.

CONCLUSION

Our findings confirm that residence of rural area is associated with a significant lower prevalence of allergic sensitization and symptoms in school children. Several risk and protective factors related to environment and style of life could be identified in both environments.

Atopy and asthma in rural Poland: a paradigm for the emergence of childhood respiratory allergies in Europe

BACKGROUND

We hypothesized that, in south-west Poland, a 'rural' protective effect on atopy and respiratory allergies would be most pronounced among children but that at all ages would be stronger among those with a rural background.

METHODS

A cross-sectional survey of the inhabitants (age >5 years, n = 1657) of Sobotka, a town of 4000 people in south-west Poland: and seven neighbouring villages. We measured and analysed responses to skin prick tests (atopy) and to a standard questionnaire (asthma and hayfever).

RESULTS

Atopy was very uncommon (7%) among villagers at all ages but not among townspeople (20%, P < 0.001); the differences were most marked among those aged under 40 years. Asthma and hayfever were similarly distributed, both being very rare among villagers. The differences appear to be explained by the cohort effect of a communal move away from rural life. This interpretation is supported by an ecological correlation (rho = -0.59) between rural populations and childhood wheeze in 22 European countries.

CONCLUSION

The very striking differences in the prevalence of allergy between these two neighbouring communities of central Europe reflect the pan-continental population movements that may have been responsible for the emergence of childhood allergies in Europe.

[Time trends in prevalence of symptoms of allergic rhinitis in 13-14 year-old schoolchildren in 8 areas of Spain between 1993-1994 and 2001-2002 according to the International Study of Asthma and Allergies in Childhood (ISAAC)]

BACKGROUND AND OBJECTIVE

Our goal was to estimate the time trends in the prevalence of symptoms of allergic rhinitis (AR) and its geographic variations.

POPULATION AND METHOD

During 2001-2002, the phase 3 of ISAAC study was carried out, and a comparison with the phase 1 (1993-1994) was done. This cross sectional study included 30,046 schoolchildren 13-14 years-old from 9 centers (Asturias, Barcelona, Bilbao, Cartagena, Castellon, Madrid, Pamplona, Valencia, and Valladolid). A questionnaire about rhinitis symptoms self-administered to schoolchildren was used at schools and institutes with a participation rate of 100% to 75.8%.

RESULTS

A divergent time trend of AR prevalence symptoms was observed with a decrease in Barcelona and Bilbao, a stabilization in Cartagena, Pamplona, and Valencia, and an increase in Castellon; Madrid and Valladolid; however, there was an overall increase in nasal allergy. The prevalence of rhinoconjunctivitis in the past year (Prevalence Ratio [PR] = 1,13; 95% Confidence Interval [CI], 1.07-1.19) and nasal allergy ever (PR = 1.22; 95% CI, 1.15-1.30) increased after adjusting for gender, center and season change. The prevalence of rhinoconjunctivitis and nasal allergy varied according to centres, Madrid, Asturias, Cartagena and Bilbao exhibiting the higher prevalence. Taken as a whole, these data indicate a middle prevalence of AR when compared with other countries following an ISAAC methodology.

CONCLUSIONS

Two patterns of time trend of prevalence of symptoms of AR were observed. The investigation of risk factors at local level could be important in order to undertake preventive measures.

[Identification of the allergenic taxa of pollen in patients with pollinosis to determine the risk season]

BACKGROUND

Determining the risk season for the presence of pollen in the atmosphere aids primary care physicians in the diagnosis and treatment of allergic diseases. Our objective was to identify the taxa of pollen that cause allergic rhinoconjunctivitis in a sample of patients from a health center who presented seasonal symptoms.

METHODS

We designed an observational, cross-sectional, non-randomized study to be carried out in the Cazoña Health Center in Santander, Spain. We selected 30 volunteers of both sexes, aged between 13 and 69 year old, who suffered seasonal rhinoconjunctivitis symptoms and who had always lived in Santander. Patients underwent skin-prick tests with the 25 pollen extracts routinely used in Spain, house dust mite (HDM), cat dander and Alternaria extracts by means of the Prick-Film system. The test result was expressed as the percentage of the papule area caused by histamine. Measurement was performed by scanning the copied papule area with the Prick-Scan program for PC.

RESULTS

All patients were positive to grass pollen, 26 % were sensitized to grass pollen only and 23 % were also sensitized to other non-pollen allergens. Twenty-seven percent tested positive to Plantago, 20 % to Quercus and 13 % to Morus; the remaining pollen extracts were positive in less than 10 %. Fifty-six percent of the patients were positive to HDM and 6 % to cat dander.

CONCLUSIONS

A warning period for pollinosis patients in the city of Santander can be defined. In our case, the important period is the grass pollen season, since the remaining pollen taxa sensitized few patients. Most of our patients were also sensitized to HDM.