Risk Of Hay Fever Research Articles

Perinatal Risk Factors for Hay Fever — A Study Among 2550 Finnish Twin Families

AbstractPrevious studies have suggested that perinatal factors influence the risk for asthma but population studies on perinatal factors and risk for hay fever are few. We studied the effect of perinatal factors on the risk for hay fever among adolescent twins by a questionnaire study involving five consecutive nation-wide birth cohorts of 16-year-old twins and their parents. The risk for parent-reported, doctor-diagnosed hay fever in the adolescents associated with several perinatal characteristics was assessed with logistic regression analysis among individuals and by a discordant pair analysis. In the univariate analysis of the birth factors, the risk for hay fever increased with increasing birth weight (pfor trend = 0.048, OR for those ≥ 3000g 1.35, 95% CI 0.91–2.02 compared to those < 2000g) and gestational age (pfor trend = 0.04, OR for those born after 40 weeks of gestation 2.24, 95% CI 1.03–4.86, compared to those born before 33 weeks of gestation) and was lower in those subjects hospitalised in the neonatal period (OR 0.74, 95% CI 0.58–0.93). Because of significant interactions between parental hay fever status and birth factors (ponderal index,p= 0.03 and maternal agep= 0.04), stratified analysis were performed. The positive association between birth weight and hay fever was most obvious among adolescents with no parental history of hay fever (pfor trend = 0.03). Similar, though not significant, trends were found with other birth factors among these families, whereas no such trend was found among adolescents with parental hay fever, suggesting that gestational maturity increases the risk for hay fever in the absence of genetic predisposition. However, of the perinatal factors only neonatal hospitalisation (OR 0.75, 95% CI 0.59–0.96) remained a significant risk factor for the development of hay fever, when adjusted for non-perinatal factors.

What should we tell allergic families about pets?

What should we tell allergic families about pets?

Cross-sectional study on cytokine polymorphisms, cytokine production after T-cell stimulation and clinical parameters in a random sample of a German population.

We investigated, in a random sample of a German population, the association of polymorphisms in the genes encoding the cytokines interleukin 2 (IL-2), interleukin 4 receptor (IL-4R), interleukin 6 (IL-6), interleukin 10, interferon gamma (IFNG), tumor necrosis factor (TNF) and intercellular adhesion molecule 1 (ICAM-1) with (1) secreted levels of the respective proteins after T-cell stimulation and (2) data on selected diseases obtained from a questionnaire. The scope of this investigation was to further the understanding of the genetic background of allergies and common colds and the observed heterogeneity of many immune responses in the human population. In contrast to previous reports that showed associations of promoter polymorphisms of cytokine genes with the production of the corresponding protein, we did not find associations with protein release after T-cell stimulation in vitro. Among the correlations with the clinical parameters, we observed an increased risk of allergies (odds ratio, OR= 4.1; confidence interval, CI: 1.6-10.4), particularly hay fever (OR=5.6, CI: 1.8-17.1) in individuals homozygous for IFNG 13 CA-repeats. In combination with the TNF wildtype, the risk for hay fever increased to OR=8.4 (CI: 2.7-25.6). Furthermore, individuals with a combination of IL2, IL6 and ICAM-1 polymorphisms tended to have higher frequencies of reported common colds than individuals with the alternate genotypes. As these are results of an explorative investigation, these findings require confirmation in material from a different source. If confirmed, these relationships could contribute to a better characterisation of the genetic component of allergies.

The initial care of newborn infants and subsequent hay fever

Patterns of neonatal exposure to microorganisms have changed substantially over the last 100 years, and it has been suggested that this has influenced the risk of immune-mediated disease. Using a proxy measure, we tested the hypothesis that the initial handling of newborn infants, which is known to affect the pattern of exposure to microorganisms, may alter the risk of developing subsequent atopy, as indicated by hay fever. Analysis was performed on 5,519 members of the 1970 British Cohort Study, a nationally representative birth cohort. Cohort members with hay fever were identified at intervals up to the age of 26 years. Details of neonatal care and childhood circumstances were recorded prospectively. Those who had spent their first night away from their mother in the communal infant nursery were selected as likely to have experienced atypical exposure compared with infants who remained with their mother. Adjustment was made for potential confounding factors in infancy and childhood by multiple logistic regression analysis. Unadjusted relative odds (with 95% CI) for developing hay fever among those spending the first night in the communal nursery, when compared with other infants who remained with the mother, were 1.48 (1.23-1.77), P<0.001. Comprehensive adjustment for the potential confounding factors, including feeding practices on the first day of life, markers of social and material circumstances, and region, did not substantially alter this relationship, with adjusted relative odds of 1.31 (1.08-1.59), P=0.005. While our proxy measure is associated with an increased risk of hay fever, further research is required to confirm that this is due to the pattern of infectious exposure in very early life. The results are consistent with the hypothesis that the first challenges are particularly important in the development of the newborn infant's immune system.

Allergic diseases in farmers' children.

Several studies have reported lower rates of allergic sensitization and allergies in children living in rural as compared to urban communities. This has been attributed to the lower levels of air pollution in rural areas. The question arises whether other factors in the rural environment could explain the lower prevalence rates of allergic sensitization and hay fever. A first report from rural South Bavaria in Germany demonstrated that children living in a home where coal and wood were used for heating had a significantly lower risk of suffering from hay fever (odds ratio 0.57 (0.34-0.98)), of being sensitized to common allergens (OR 0.67 (0.49-0.93)) and of having bronchial hyperresponsiveness (OR 0.55 (0.34-0.90)) than their peers living in homes with other heating systems. Subsequently, the Swiss Study on Childhood Allergy and Respiratory Symptoms with Respect to Air Pollution (SCARPOL) tested the hypothesis that farming as parental occupation was associated with a lower risk of hay fever and atopy. A total of 1620 (86.0%) 6-15-year-old schoolchildren living in three rural communities of Switzerland were examined using a standardized questionnaire completed by the parents and IgE antibodies against six common aeroallergens in serum samples of 404 (69.3.0%) of the 13-15-year-olds. Farming as parental occupation was significantly associated with lower rates of reported hay fever symptoms and allergic sensitization. Comparing children from farming with those from non-farming environments, the adjusted OR was 0.34 (95% CI: 0.12-0.89) for sneezing attacks during the pollen season, and 0.31 (95% CI: 0.13-0.73) for a sensitization to allergens. These results have recently been confirmed in a new and much larger survey in rural South Bavaria. Several alternative explanations have to be considered when interpreting these findings, namely, selection bias, the development of tolerance, increased microbial stimulation and a more traditional lifestyle (diet and housing conditions). Based on present knowledge, the underlying environmental factor explaining the protective effect of the farming environment has not yet been identified.

Reduced risk of hay fever and asthma among children of farmers.

The prevalence of atopic diseases is on the rise. Traditional lifestyles may be associated with a reduced risk of atopy. To test the hypothesis that children living on a farm have lower prevalences of atopic diseases. To identify differences in living conditions between farmers and other families which are associated with the development of atopic conditions. Cross-sectional survey among children entering school (aged 5-7 years). A written questionnaire including the ISAAC core questions and asking for exposures on a farm and elsewhere was administered to the parents. School health entry examination in two Bavarian districts with extensive farming activity. 10 163 children. The prevalence of doctor's diagnoses and symptoms of hay fever, asthma and eczema as assessed by parental report. Farmers' children had lower prevalences of hay fever (adjusted odds ratio = 0. 52, 95% CI 0.28-0.99), asthma (0.65, 0.39-1.09), and wheeze (0.55, 0. 36-0.86) than their peers not living in an agricultural environment. The reduction in risk was stronger for children whose families were running the farm on a full-time basis as compared with families with part-time farming activity. Among farmers' children increasing exposure to livestock was related to a decreasing prevalence of atopic diseases (aOR = 0.41, 95% CI 0.23-0.74). Factors related to environmental influences on a farm such as increased exposure to bacterial compounds in stables where livestock is kept prevent the development of allergic disorders in children.

Measles infection, measles vaccination and the effect of birth order in the aetiology of hay fever.

It has recently been suggested that measles infection may reduce the risk of atopy. To study the independent effect of measles infection and measles vaccination on the occurrence of hay fever in a British national birth cohort. In over 6000 children born in 1970, details of immunizations and childhood diseases were collected by parental interviews at ages 5, 10 and 16 years, and hay fever within the past year at age 16 years. In univariate analysis, hay fever was less common in those contracting measles infection than in those not infected (OR 0.86, 95% CI 0.76-0.96), and more common in those given measles vaccination than in those not vaccinated (OR 1.16, 95% Cl 1.03-1.31). However, these effects were strongly confounded by birth order, which was closely associated with the likelihood of receiving measles vaccination and with the risk of hay fever. A strong interaction between the effects of measles vaccination and infection, and birth order was found, such that in those with many older sibling contacts, hay fever was significantly and independently reduced in relation to both measles infection and measles vaccination relative to those who were neither infected nor vaccinated. Both measles infection and measles vaccination in childhood appear to reduce the risk of hay fever in children with multiple older sibling contacts. Differential exposure or response to the measles virus may explain the effect of birth order on the occurrence of allergic disease.

Family size, childhood infections and atopic diseases. The Aberdeen WHEASE Group.

BACKGROUND: This study addresses the causes of the increases in childhood asthma and allergic disease. On the basis of an observed inverse relationship between family size and allergic disease or...

Family structure, neonatal infection, and hay fever in adolescence.

To determine whether increased numbers of siblings and infection in early life protect against allergic sensitisation. Historical cohort study. Sheffield, UK. 11,765 children aged 11-16 years for whom a history of neonatal infectious illness had been recorded systematically at 1 month of age. A history of hay fever and family structure was obtained by postal questionnaire; neonatal illness history was ascertained from health visitor records; 723 children underwent skin prick testing with mixed grass pollen extract. The prevalence of hay fever was reduced (p < 0.0001) among children of younger mothers, and those from larger families. The number of older siblings exerted a stronger independent effect than the number of younger siblings (p < 0.001). Infants breast fed exclusively during the first month were at higher risk (p < 0.05) of subsequent hay fever, independent of demographic factors. Adolescents at high risk of hay fever by virtue of their family structure were more likely to be sensitised to grass pollen (p < 0.002). No significant relations emerged between hay fever and infection in the first month of life, even among children born in June. The association of hay fever with family structure is not due to reporting bias and reflects an environmental influence on allergic sensitisation. The effects of sibship size, birth order, and infant feeding are consistent with a protective influence of postnatal infection. The first month of life and the first postnatal exposure to allergen are not the critical periods during which this protective effect is determined.