Socioeconomic risk factors in the prevalence of asthma and other atopic diseases in children 6 to 7 years old in Valencia Spain

Prevalence and factors linked to atopic eczema in 10- and 11-year-old schoolchildren. Isaac 2 in Almeria, Spain

BACKGROUND

Atopic eczema affects 5-10% of the Spanish paediatric population, and has increased in frequency over the last few decades, probably due to changes in the environment and lifestyle. Phase II of the ISAAC (International Study of Asthma and Allergies in Childhood) uses a standardised methodology to establish the prevalence of allergic disorders and factors linked to them in each centre.

OBJECTIVES

To assess the prevalence and severity of atopic eczema, and to establish factors linked to atopic eczema in 10-11 year-old school children in the city of Almeria (South-East coast of Spain).

MATERIAL AND METHODS

An ecological study was carried out as part of ISAAC II, using homologated questionnaires and allergic tests in 1143 schoolchildren. Statistic association was assessed by means of chi(2) test, and then logistic regression analysis was performed with the most significant variables from the univariant analysis.

RESULTS

The prevalence of atopic eczema was 11.4%. The risk factors found in the multiple logistic regression analysis were: personal antecedents of severe asthma (OR 19 CI 95% 1.35-266) and severe rhinitis (OR 7.7 CI 95% 1.79-33), fungi in bedroom during the first year of life (OR 4.2 CI 95% 1.17-15.1) and atopic eczema in one parent (OR 5.2 CI 95% 2.69-10.1).

CONCLUSIONS

The prevalence of atopic eczema is similar to that found in other studies within ISAAC Phase I. The most important risk factors for atopic eczema are family and personal history of other atopic diseases and the presence of fungi in the home.

Epidemiology and burden of rhinitis and rhinoconjunctivitis in 9- to 11-year-old children

BACKGROUND

Rhinoconjunctivitis (RC) is regarded as the most common chronic disease of childhood; however, the currently available epidemiological studies on prevalence, burden, and risk factors of RC are insufficient. This analysis aimed to investigate potential risk factors, symptom frequency, and burden of RC.

METHODS

Using the International Study of Asthma and Allergies in Childhood Phase II questionnaires, 6963 elementary school children aged 9-11 years were surveyed in five different city centers of Turkey. All participants were skin-prick tested with common aeroallergens.

RESULTS

The prevalence of ever rhinitis, physician-diagnosed rhinitis, current rhinitis, and current RC were 51.6, 31.0, 43.5, and 23.1%, respectively; 19.8% of children with RC symptoms were atopic to at least one allergen. Among students with RC symptoms, 42.2, 23.9, 35.8, and 28.2% reported moderate-severe interference of daily activities, at least 1 day of absence from school, visit to a health care professional, and any drug usage for rhinitis, respectively. Nasal decongestants and oral antihistamines were the most frequently used treatment. Approximately 70% of RC patients reported perennial symptoms and 42.8% were classified as mild to intermittent. Multivariate logistic regression analysis revealed family history of asthma and/or allergic rhinitis (odds ratio [OR] = 1.863; confidence interval, [CI] = 1.583-2.191; p < 0.001), living in a house with mold and dampness in the 1st year of life (OR = 1.651; CI = 1.356-2.01; p < 0.001), maternal smoking in pregnancy (OR = 1.425; CI = 1.089-1.864; p = 0.011), low monthly income (OR = 1.685; CI = 1.422-1.998; p = 0.001), current wheezing (OR = 2.543; CI = 2.151-3.006; p = 0.001), and current atopic eczema (OR = 2.503; CI = 1.96-3.196; p = 0.001) as significant risk factors for current RC.

CONCLUSION

Along with the high prevalence of RC in childhood, underdiagnosis and undertreatment of the disease are also frequent. The socioeconomic burden of the disease can be reduced by increasing awareness and proper diagnosis/treatment.

Contact to cat or dog, allergies and parental education

Whether or not associations between animal contact and allergy/atopy are homogeneous across social strata has not yet been investigated. The aim of this study was to estimate the association between animal contact (cat, dog) and allergy/atopy in 6-yr-old school beginners, stratified by parental educational level. A total of 30794, 6-yr old children participated in cross-sectional studies between 1991 and 2000 in Germany. Allergic sensitization to common aeroallergens and symptoms and diagnoses of atopic diseases (asthma, eczema, hay fever) were the dependent variables. Contact with dog/cat were the independent variables. Logistic regression was used to adjust for confounding. Analyses were stratified for parental education. Prevalences of hay fever, eczema, specific sensitization to pollen and house dust mite increased, while the prevalence of contact to cat and dog decreased with parental educational level. Globally significant positive associations between cat contact and sensitization to cat (interaction significant) and between dog contact and wheezing remained significant in the highest and medium/highest educational strata respectively. A globally significant inverse association between cat contact and hay fever remained significant in the highest educational stratum only. The inverse association of contact to dog with eczema was globally significant, but not in the strata. When estimating the associations between animal contact and allergy/atopy in children, effect modification by social status should be considered. Cat contact seems to increase the odds of sensitization to cat only in children whose parents have a high level of education.

Environmental tobacco smoke (ETS) and respiratory health in children

Environmental tobacco smoke (ETS) is a major risk factor for poor lung health in children. Although parental smoking is the commonest source of ETS exposure to children, they are also exposed to ETS in schools, restaurants, public places and public transport vehicles. Apart from containing thousands of chemicals, the particle size in the ETS is much smaller than the main stream smoke, and therefore has a greater penetrability in the airways of children. Exposure to ETS has been shown to be associated with increased prevalence of upper respiratory tract infections, wheeze, asthma and lower respiratory tract infections. Even developing fetuses are exposed to ETS via the umbilical cord blood if the mother is exposed to tobacco smoke. The placenta also does not offer any barrier to the penetration of ETS into the fetus. The immune system in these babies is more deviated toward the allergic and asthmatic inflammatory phenotype and therefore makes them more prone to develop asthma later in life. An increased awareness of the harmful effects of ETS on children's health is warranted.

Cellular and molecular mechanisms in atopic dermatitis

Atopic dermatitis (AD) is a pruritic inflammatory skin disease associated with a personal or family history of allergy. The prevalence of AD is on the rise and estimated at approximately 17% in the USA. The fundamental lesion in AD is a defective skin barrier that results in dry itchy skin, and is aggravated by mechanical injury inflicted by scratching. This allows entry of antigens via the skin and creates a milieu that shapes the immune response to these antigens. This review discusses recent advances in our understanding of the abnormal skin barrier in AD, namely abnormalities in epidermal structural proteins, such as filaggrin, mutated in approximately 15% of patients with AD, epidermal lipids, and epidermal proteases and protease inhibitors. The review also dissects, based on information from mouse models of AD, the contributions of the innate and adaptive immune system to the pathogenesis of AD, including the effect of mechanical skin injury on the polarization of skin dendritic cells, mediated by keratinocyte-derived cytokines such as thymic stromal lymphopoietin (TSLP), IL-6, and IL-1, that results in a Th2-dominated immune response with a Th17 component in acute AD skin lesions and the progressive conversion to a Th1-dominated response in chronic AD skin lesions. Finally, we discuss the mechanisms of susceptibility of AD skin lesions to microbial infections and the role of microbial products in exacerbating skin inflammation in AD. Based on this information, we discuss current and future therapy of this common disease.

Allergic rhinoconjunctivitis: epidemiology

Allergic rhinoconjunctivitis has been studied much less frequently than asthma using epidemiologic approaches. Population-based studies are difficult to conduct because of misclassification arising from the reliance on self-reported questionnaires that use terms such as allergic rhinitis or hay fever to establish the diagnosis. In addition, many epidemiologic studies focus on diagnostic skin testing or allergen-specific IgE antibodies (RASTs) as an objective outcome to assess for hay fever. These techniques are helpful but not perfect measures for predicting hay fever outcomes in epidemiologic studies. It is generally accepted, however, that allergic rhinoconjunctivitis is one of the most common of chronic diseases and is the most common atopic disorder. This article reviews the definition of allergic rhinoconjunctivitis, the epidemiology of this disorder from infancy into adulthood, and environmental risk factors for development of sensitization to certain allergens.

Socioeconomic risk factors for asthma in Chilean young adults

OBJECTIVES

We studied the association between socioeconomic status (SES) and asthma symptoms, severity of asthma, atopy, and bronchial hyperresponsiveness (BHR) to methacholine.

METHODS

We studied 1232 men and women born between 1974 and 1978 in a semirural area of Chile. We assessed asthma symptoms with a standardized questionnaire, atopy with a skin-prick test to 8 allergens, and BHR to methacholine with the tidal breathing method. SES was derived from several indicators: education, occupation, completion of a welfare form, belongings, housing, number of siblings, and overcrowding.

RESULTS

Those with fewer belongings had more asthma symptoms. Those who had higher education and those who owned cars had fewer asthma symptoms and BHR. Overcrowding was negatively related to atopy, atopy with asthma symptoms, and BHR. Higher education and noncompletion of a welfare form were risk factors for atopy.

CONCLUSION

The strength and direction of the association between asthma and SES depended on what definition of asthma was analyzed. Asthma symptoms were more common among poor people. There was some support for the hygiene hypothesis, as overcrowding was associated with less wheezing with atopy, less atopy, and less BHR.

School education and allergic sensitization in adults

BACKGROUND

There is evidence of an association between socioeconomic status (SES) and atopy mainly from studies in children which investigated atopic diseases and parental SES. We determined the association of allergic sensitization, as measured by skin prick test (SPT) and allergen-specific IgE (RAST), and SES in a population-based study in adults.

METHODS

Within a population-based, nested, case-control study, a standardized interview was performed and allergic sensitization to common aeroallergens was determined by SPT and RAST.

RESULTS

A total of 1537 adults (50.4% female, age: median 50.0, range 28-78 years) were investigated, half of whom (50.2%) exhibited at least one positive RAST result according to the study design. SPT reactivity was 37.3% in this group and was estimated to be 26.1% in the representative study base of 4178 adults. Within increasing categories of school graduation (none; after 8, 10, 13, and >13 years), the prevalence of SPT (20.5%, 31.3%, 44.0%, 44.2%, 48.1%; P trend <0.0001) and RAST reactivity (35.0%, 48.0%, 52.3%, 48.4%, 58.4%; P trend=0.004) increased continuously. Similar results were obtained when testing this association on the level of single allergens. After control for age, sex, and parental history of atopic diseases, all but the first odds ratios for SPT remained significant (first category=reference, 2.06, 3.21, 3.88, 3.96). The same model for RAST reactivity revealed a similar result with effect estimate for the last category being significant (first category=reference, 1.89, 2.08, 2.10, 2.81).

CONCLUSIONS

Allergic sensitization (SPT and RAST) to common aeroallergens in adults follows a significant and linear association with school education.