HLA in eczema and hay fever.

The presumed HLA haplotype A1:B8 was more frequent and the combination of A3 and B7 was less frequent in allergic subjects presenting with eczema, than in those presenting with hayfever. A1:B8 was most frequent (36%) in eczema complicated by asthma and/or hay fever, and least frequent (5%) in hay fever alone, considerably above and below the frequency in the general population (17%).     

The eczema risk variant on chromosome 11q13 (rs7927894) in the population-based ALSPAC cohort: a novel susceptibility factor for asthma and hay fever

In a genome-wide association study, a common variant on chromosome 11q13.5 (rs7927894[T]) has been identified as a susceptibility locus for eczema. We aimed to analyze the effect of this risk variant on asthma and hay fever and to determine its impact on the general population level in over 9300 individuals of the prospectively evaluated Avon Longitudinal Study of Parents and Children birth cohort. We demonstrate an association of rs7927894[T] with atopic asthma and with hay fever. The largest effect sizes were found in patients with the combined phenotype atopic asthma plus eczema [odds ratio (OR) = 1.50; 95% confidence interval (CI) 1.20-1.88; P = 3.7 × 10(-4)] and hay fever plus eczema (OR = 1.37; 95% CI 1.15-1.62; P = 3.8 × 10(-4)). We replicated the effects of rs7927894[T] on eczema-associated asthma and hay fever independently in the German GENUFAD (GEnetic studies in NUclear Families with Atopic Dermatitis) study and show that they are significantly larger than the effect observed in eczema. The estimated population attributable risk fractions for eczema, eczema-associated atopic asthma or hay fever were 9.3, 24.9 and 23.5%, respectively. Finally in eczema, we found a synergistic interaction of rs7927894[T] with filaggrin gene (FLG) mutations, which are a major cause of epidermal barrier dysfunction, and replicated the interaction in the German Multicenter Allergy Study birth cohort. The synergistic effect of rs7927894[T] and FLG mutations on eczema risk as well as the association of both variants with eczema-associated atopic asthma and hay fever point to an involvement of rs7927894[T] in a functional pathway that is linked to the barrier defect.     

The association of family size with atopy and atopic disease

Background Studies in children have shown that family size is negatively associated with atopy and atopic disease. Objective To describe the association of family size with atopy and atopic disease in young adults. Methods A randomly selected sample of 1159 men and women aged 20–44 years provided information on respiratory symptoms, hay fever and eczema. Blood samples were taken for assessment of total IgE and specific IgE to house dust mite, grass, cat, Cladosporium and birch. The association of family size and birth order with respiratory symptoms, atopy and total IgE was assessed by multiple logistic and linear regression. Results There was a negative association between family size and the reporting of ‘wheeze with breathlessness’ (adjusted odds ratio for an increase of one sibling 0.85; 95% confidence interval 0.75–0.98), ‘wheeze without a cold’ (adjusted odds ratio for an increase of one sibling 0.85; 95% confidence interva l0.75–0.98) and ‘asthma attacks’ in the last 12 months (adjusted odds ratio for an increase of one sibling 0.77; 95% confidence interval 0.61–0.97), current ‘hayfever and nasal allergies’ (adjusted odds ratio for an increase of one sibling 0.84; 95% confidence interval 0.75–0.94) and sensitization to grass (adjusted odds ratio for an increase of one sibling 0.87; 95% confidence interval 0.76–0.99). Birth order was negatively associated with ‘hayfever and nasal allergies’ only. A decreased risk of sensitization to grass in those from large families did not fully explain the negative association between family size and hayfever. No statistically significant (P > 0.05) association of family size or birth order with the reporting of other respiratory symptoms, eczema, sensitization to the other allergens or total IgE was observed. Conclusion There is a negative association between family size and some symptoms suggestive of asthma, ‘hayfever and nasal allergies’ and sensitization to grass in young adults. There is no consistent, significant association between family size and eczema, total IgE or sensitization to other allergens.     

Extrinsic and intrinsic asthma: influence of classification on family history of asthma and allergic disease

The distributions of asthma, hay fever and eczema were examined in the first degree relatives of 516 asthmatics grouped according to atopic status, history of hay fever/eczema and history of asthma provoked by pollens, dust or animals. The prevalences of both asthma and eczema in relatives were strongly correlated with the presence of hay fever/eczema in probands and to a lesser extent with their atopic status. The prevalence of hay fever in relatives was strongly correlated with both the presence of hay fever/eczema and the degree of atopy in probands. In contrast, allergic provocation of asthma in probands did not influence the prevalences of asthma, hay fever or eczema. These findings are consistent with the hypothesis that there is an increased risk of asthma in relatives of atopic asthmatics which may arise from the enhanced susceptibility to asthma of individuals who inherit both a predisposition to asthma and a predisposition to atopy.     

Does the use of antibiotics in early childhood increase the risk of asthma and allergic disease?

BACKGROUND: One of the mechanisms evoked to explain the increasing prevalences of asthma and allergy, in particular among children, is the 'Western lifestyle' or 'hygiene' hypothesis. As early childhood infections are assumed to hold a protective effect on the development of asthma and allergies, the use of antibiotics at that sensitive age may lead to an increased risk of asthma and allergy. OBJECTIVE: The aim of this study is to investigate the association between the use of antibiotics in the first year of life and the subsequent development of asthma and allergic disorders. METHODS: In a population-based sample of 7-and-8-year-old children questionnaire and skin prick test data were collected from 1206 and 675 subjects, respectively. Prevalence rates of asthma, allergic disorders and skin test positivity were compared between children with and without early life use of antibiotics, taking into account other possible risk factors including early respiratory infections. The effect of genetic predisposition was investigated by stratified analyses of children with and without parental hay fever. RESULTS: The use of antibiotics during the first year of life was significantly associated with asthma (OR = 1.7, 95% CI 1.0-3.1), hay fever (OR = 2.3, 95% CI 1.3-3.8) and eczema (OR = 1.3, 95% CI 1.0-1.8). No significant relationship was found with skin test positivity (OR = 1.1, 95% CI 0.7-1.7). After stratification for the presence of parental hay fever, children without parental hay fever did not show any significant associations between antibiotics use and asthma or allergy, whereas in children with parental hay fever the use of antibiotics was significantly related with asthma (OR = 2.3, 95% CI 1.1-5.1), hay fever (OR = 2.8, 95% CI 1.5-5.1) and eczema (OR = 1.6, 95% CI 1.0-2.6), and of borderline statistical significance with skin test positivity (OR = 1.6, 95% CI 0.9-3.0). CONCLUSION: Early childhood use of antibiotics is associated with an increased risk of developing asthma and allergic disorders in children who are predisposed to atopic immune responses. These findings support recent immunological understanding of the maturation of the immune system.     

Filaggrin mutations in the onset of eczema, sensitization, asthma, hay fever and the interaction with cat exposure

Background:  Filaggrin gene ( FLG ) mutations contribute to the development of eczema and asthma, but their contribution to sensitization and hay fever remains unclear.
Methods:  FLG mutations R501X, 2282del4 and R2447X were genotyped in the Prevention and Incidence of Asthma and Mite Allergy birth cohort ( n  = 934) to evaluate longitudinally, for up to 8 years, their association with eczema, sensitization, asthma, hay fever and their interaction with cat exposure.
Results:  The combined FLG mutations were significantly associated with eczema at all ages when occurring in the first year of life (OR = 2.0; 95% CI: 1.4–2.8). Combined FLG mutations were associated with both atopic and nonatopic eczema, as well as asthma (OR = 3.7; 95% CI: 1.8–7.5). When the FLG 2282del4 mutation was analysed separately, it was significantly associated with the development of eczema during the first year, having eczema up to 8 years and sensitization at the age of 8 years, which was enhanced by early-life cat exposure (ORs being 8.2; 95% CI: 2.6–25.9, 6.0; 95% CI: 3.2–11.3 and 5.4; 95% CI: 1.2–23.6 respectively). FLG 2282del4 was significantly associated with hay fever from the age 5 years onwards (OR = 3.9; 95% CI: 1.5–10.5).
Conclusions:  FLG mutations are associated both with atopic and nonatopic eczema starting in the first year of life. FLG mutations combined with eczema in the first year of life are associated with a later development of asthma and hay fever, a clear example of the atopic march. We confirm that cat exposure enhances the effect of a FLG mutation on the development of eczema and sensitization.     

Neonatal head circumference, neonatal weight, and risk of hayfever, asthma and eczema in a large cohort of adolescents from Sheffield, England

BACKGROUND: Neonatal physical characteristics, including head circumference and birth weight, have been hypothesized to be markers of in utero thymic development. Greater head circumference and lower birth weight have been linked in previous studies to subsequent development of asthma, and greater birth weight has been associated with subsequent development of eczema. OBJECTIVE: To investigate potential associations between neonatal head circumference and weight and hayfever, asthma and eczema in a cohort of adolescents from Sheffield, England. METHODS: Responses to a questionnaire inquiring about physician-diagnosed hayfever, asthma and eczema among adolescents in Sheffield, England, were linked to previously recorded measurements of weight at birth and at 1 month and head circumference at 1 month. Logistic regression methods were used to relate diagnoses to neonatal measurements and potential confounders. RESULTS: The cohort consisted of 10,809 adolescents, of whom 16.5% reported hayfever, 18.0% asthma, and 16.2% eczema. After adjusting for sex, age at the time of the questionnaire, maternal age and gestational age at birth, number of older and younger siblings, time since birth of next older sibling, neonatal sickness, type of neonatal feeding, and maternal and paternal educational backgrounds, hayfever was the only disease associated with neonatal measurements. Comparing the highest with the lowest fifths of distributions, lifetime prevalence of hayfever was positively associated with neonatal head circumference (adjusted odds ratio 1.23, 95% CI 1.03 to 1.47) and with birth weight (1.17, 0.99 to 1.39). Hayfever was inversely related to the ratio of head circumference to birth weight (0.89, 0.75 to 1.05) and to gestational age. The associations with head circumference and birth weight were not substantially altered by further adjustment for gestational age. CONCLUSION: Greater neonatal head circumference may be associated with an increased risk of hayfever, but the inverse relationship between hayfever prevalence and the ratio of head circumference to birth weight challenges the prior hypothesis that greater head circumference relative to body mass reflects abnormal thymic development in utero, increasing the likelihood of allergic sensitization.     

Lifelong farm exposure may strongly reduce the risk of asthma in adults

BACKGROUND: Farm exposures may protect against childhood asthma, hay fever and eczema. Whether farm exposures also confer protection in adult farmers remains unclear. Moreover, little is known about the role of timing of exposure. We assessed the effects of current and childhood farm exposures on asthma, hay fever and eczema in farmers and a rural nonfarming control population. METHODS: We conducted a cross-sectional questionnaire survey in 2509 farming families (response rate 78%) and 1001 nonfarming families (response rate 67%), which included 4288 farmers and 1328 nonfarmers. RESULTS: Farmers were less likely to have asthma symptoms, hay fever and eczema; no significant differences were observed among dairy, sheep and beef, and horticulture farmers. A combination of current and childhood exposure was more strongly associated with shortness of breath (OR 0.50, CL 0.39-0.66), wheeze (OR 0.60, CL 0.49-0.73), asthma medication (OR 0.48, CL 0.37-0.63); and asthma ever (OR 0.56, CL 0.46-0.68) than current exposure alone (OR 0.63, CL 0.47-0.84; OR 0.80, CL 0.65-0.99; OR 0.68, CL 0.51-0.9; OR 0.69, CL 0.56-0.85 respectively) or childhood exposure alone (OR 0.97, CL0.65-1.44; OR 1.01, CL 0.75-1.34; OR 0.78, CL 0.51-1.19; OR 0.87, CL 0.63-1.19 respectively). Moreover, the combined number of years of farm exposure in childhood and adulthood showed a dose-dependent inverse association with symptom prevalence. CONCLUSIONS: Although both current and childhood farm exposures may play a role in the observed low prevalence of asthma symptoms in adult farmers, continued long-term exposure may be required to maintain optimal protection.     

Asthma, allergy and atopy in southern Chinese school students

In order to determine the prevalence of asthma, allergy and atopy in southern China and the relative importance of atopy and parental history in predicting asthma and allergic diseases, we carried out a cross-sectional study on 737 secondary school students aged 12-20(492 boys, 245 girls; mean age = 16.4 years, so = 1.8 years) in the city of San Bu, Guangdong, China. Standard questionnaires on respiratory and allergic symptoms were distributed for completion by parents with an overall response of 98.6%. Skin-prick tests to common aeroallergens were performed on 647 subjects (87.8%) to determine atopic status. The prevalence (and 95% CI) of a history of hay fever, eczema, wheeze or asthma ever and wheeze in past 12 months were 1.6% (0.7-2.5), 10.4% (8.2-12.6), 1.9% (0.9-1.9) and 1.1% (0.3-1.9) respectively. Forty-nine per cent (45.2-52.9) of students had one or more positive skin tests to common aeroallergens. Amongst atopic subjects, 87.3% reacted to house dust mite (Dermatophagoides pteronyssinus) and 73.3% to cockroach. There was a close association between the degree of atopy and the prevalence of a history of wheeze (P < 0.05) but not with hay fever or eczema. After adjusting for age and sex, parental histories of hay fever, eczema and wheeze were strongly associated with the respective symptoms in the subjects (OR = 17.4 (3.2-93.9) for hay fever, 27.4 (12.7-59.0) for eczema, 79.4 (21.9-288.4) for wheeze). It is concluded that respiratory and allergic symptoms were uncommon in Chinese school students despite a high prevalence of atopy, and that parental history is more important in predicting asthma and allergy than atopy.     

A disparity in the association of asthma, rhinitis, and eczema with allergen-specific IgE between Finnish and Russian Karelia

BACKGROUND: A substantial variation in the association of asthma, rhinitis and eczema with elevated serum allergen-specific immunoglobulin E (sIgE) levels between different populations has been reported. Here, we wanted to clarify whether these proportions are different in Finnish and Russian Karelia, and compared the ability of questionnaires, skin prick tests (SPT) and sIgE measurements to detect atopic conditions in these adjacent areas with different living conditions. METHODS: Randomly selected schoolchildren, aged 6-16 years, and their mothers from Finland (n = 344 children, 344 mothers) and Russia (427 and 284 respectively) participated. SPTs and sIgE measurements to common inhalant and food allergens were performed. The occurrence of asthma, rhinitis, eczema and related symptoms was assessed with an International Study of Asthma and Allergies in Childhood-based questionnaire. Correlation between SPT and sIgE was estimated using the Spearman correlation coefficient. RESULTS: The rate of positive sIgE results was significantly higher in Finland among both mothers and children. Seventy-seven per cent of Finnish children and 43% of Russian children with asthma were sIgE positive. The respective figures for hay fever were 94% and 67%, and for eczema 68% and 41%. This discrepancy was similar but of lower magnitude among mothers. The overall occurrence of asthma, rhinitis and eczema was very low in Russian Karelia. The correlation between SPT and sIgE results was generally good. CONCLUSION: Asthma, rhinitis and eczema in Russian Karelia are not only rare but also, to a large extent, have no sIgE component. Therefore, the ability of questionnaires to detect sIgE-mediated atopic conditions in this area of Russia is poor.     

Clinical atopy and associated factors in primary-school pupils

To investigate potential risk factors for clinical atopy in childhood, we obtained cross-sectional data from a cohort of 1376 8-year-old pupils. Parental atopy (hay fever, asthma, eczema), gestational age, maternal smoking habits, and the child's history of asthma, hay fever, and eczema were ascertained by questionnaire. Combining the history and the result of a skin prick test using seven aeroallergens, we defined the child's atopic diseases. Of the population evaluated, 25.4% were categorized as atopic (10.2% allergic asthma, 17.3% eczema, 6.9% hay fever). As compared with the clear nonatopics (40.2%), parental atopic diseases were more prevalent in each of the atopic groups. Significant associations of the parents' and child's disease were obvious for eczema and hay fever. Low gestational age (LGA) was more frequent in children with any atopy or with an allergic asthma (odds ratio (OR) 1.7; 95% confidence interval (CI) 1.02-2.97; OR 2.8; 95% CI 1.5-5.4). Hay fever and allergic asthma occurred less frequently in girls (OR 0.5; 95% confidence interval 0.3-0.8; OR 0.6; 95% CI 0.4-0.9). In conclusion, our data underline the importance of parental atopy for the clinical outcome in the offspring. In addition, LGA appears to be a risk factor for allergic asthma and for general atopy in later life.     

Genes, environments, and sex: factors of importance in atopic diseases in 7—9–year-old Swedish twins

Various atopic manifestations among adults have been shown to be influenced mainly by genetic factors. With the increase in prevalence of atopic diseases in recent years, especially among children, a great deal of attention has been given to environmental causes. In a study of 1480 Swedish twin pairs, 7—9 years old, we examined the importance of genetic and environmental factors in asthma, hay fever, eczema, and urticaria. Structural equation model fitting showed 33–76% of the variation in liability to the diseases to be due to genetic effects. Shared environmental effects were also important for hay fever and urticaria in both sexes and for eczema among girls. The clustering of atopic disease in families was almost entirely due to a common set of genes, but each disease manifestation also seemed to have specific genes of importance. Investigation of unlike-sex twins showed that boys had a higher cumulative incidence of asthma and hay fever than girls, whereas girls had a higher incidence of eczema. Thus, it may be concluded that although genetic factors are of major importance in atopic manifestation in children, both environmental and sex-related factors play a role.     

Wheezing, asthma, hayfever, and atopic eczema in childhood following exposure to tobacco smoke in fetal life

BACKGROUND: Prenatal maternal smoking has been associated with adverse respiratory effects in childhood such as lung deficits and wheezing, but results concerning asthma, hayfever, and atopic eczema are inconsistent. OBJECTIVE: In the present study, we investigate the effects of maternal smoking in pregnancy on asthma, hayfever, atopic eczema, and wheezing in the offspring up to the age of 14-18. METHODS: The study was based on a cohort of mothers enrolled during midwife visits around the 36th week of gestation in Odense and Aalborg, Denmark, 1984-1987. Singleton, live born children (n = 11,144) were followed-up in 2002 to obtain a childhood history of atopic diseases, by means of questionnaires to the parents. Multivariate logistic regression analyses for medical diagnoses of asthma, hayfever, atopic eczema, and symptoms of wheezing before the age of 3, were carried out on 7844 children. RESULTS: After adjustment for confounders, late prenatal smoke exposure was associated with wheezing, with an odds ratio (OR) of 1.2, and a 95% confidence interval (CI) of 1.1-1.5. Furthermore, slightly reduced estimates for hayfever (OR 0.8, CI 0.7-1.0) and atopic eczema (OR 0.8, CI 0.7-0.9) were obtained for children exposed in late pregnancy compared with non-exposed. CONCLUSION: Late gestational smoke exposure was associated with wheezing but not with asthma, while null or even protective estimates were indicated for hayfever and atopic eczema. However, lack of control options for hereditary factors may have affected the results.     

The atopic syndrome: in vitro immunological characteristics of clinically defined subgroups of atopic subjects

Total IgE, selected specific IgE antibody levels, C2 and yeast opsonization were measured in four clinically defined subgroups of atopic patients who had previously been HLA-typed. Each group was characterized by a distinctive mean total IgE level and profile of specific IgE responses. All groups gave comparable levels of IgE antibodies to Timothy grass pollen but in patients initially presenting with infantile eczema and who subsequently developed asthma and/or hay fever, IgE antibodies to bovine milk proteins, egg ovalbumin and cat dander were frequently observed whereas in patients initially presenting with hay fever later in life these antibodies were usually absent. Computer assisted analysis failed to show any association between IgE antibody responses and (a) the HLA phenotypes A1,B8 and A3,B7 (b) C2 levels and (c) the yeast opsonization index.     

Is obesity a risk factor for childhood asthma?

Background: In adolescents and adults, an association between obesity and asthma was found in females. Does this sex‐specific association already exist in young children? Methods: Questionnaire data on 9357 5‐ and 6‐year‐old German children were collected in 1997 in two rural regions in Bavaria. The diagnosis of asthma, hay fever, and eczema was ascertained with the ISAAC core and other validated questions. Overweight was defined by a BMI of >90th and ≤97th percentile and obesity by a BMI of >97th percentile. Results: The lifetime prevalence of doctor's diagnosed asthma in girls was 3.5% (95% CI 2.9–4.1%) for normal weight, 5.8% (95% CI 3.2–8.4%) for overweight, and 10.3% (95% CI 5.3–15.2%) for obesity, whereas no relation to weight was found in boys. Hay fever and eczema were unrelated to weight in girls and boys. The adjusted odds ratio for asthma in girls was 2.12 (95% CI 1.22–3.68) for overweight and 2.33 (95% CI 1.13–4.82) for obesity. Conclusions: A sex‐specific association with doctor's diagnosed asthma was also observed in girls at school entry. Since this association was confined to doctor's diagnosed asthma in the absence of other atopic conditions, and no association with other atopic manifestations was found, we hypothesize that this association is related to factors other than atopic sensitization.     

A lower prevalence of atopy symptoms in children with type 1 diabetes mellitus

BACKGROUND: The Th1/Th 2 concept is a model to understand the pathophysiology of certain diseases. Atopic diseases (asthma, eczema and hayfever) are characterized by a chronic inflammatory reaction that is dominated by Th 2 cells, and type 1 diabetes mellitus (DM) is Th1 cell dominated. Because it is known that Th1 and Th 2 cells reciprocally counteract each other, it can be speculated that the prevalence of Th 2-mediated disease is lower in patients with Th1-mediated disease. OBJECTIVE: To compare the prevalence of atopic diseases between children with DM and age-matched controls. METHODS: Parents of children with DM were requested by Dutch paediatricians to complete the International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire on the prevalence of atopic diseases. A control group was derived from a Dutch cross-sectional survey (the ISAAC2 study). RESULTS: We received 555 completed questionnaires, which is estimated to be 25% of the total number of Dutch children with DM. The control group consisted of 777 children. After age-matching, the questionnaires of 188 DM patients were used. Symptoms of asthma, hayfever and eczema were reported less in the group of children with DM compared with the control group (wheeze last year, OR 0.796, 95% CI 0.408-1.554; hayfever symptoms last year, OR 0.642, 95% CI 0.369-1.118; eczema symptoms last year, OR 0.693, 95% CI 0.430-1.115). CONCLUSION: The lower prevalence of astma, hayfever and eczema symptoms in DM patients compared with age-matched controls, although not statistically significant, is consistent with the Th1/Th 2 concept.     

Allergy prevalence and causal factors in the domestic environment: results of a random population survey in the United Kingdom.

BACKGROUND: Surveys of the prevalence of allergic diseases associated with domestic allergens (eg, asthma, rhinitis, hay fever, eczema, and dermatitis) are usually undertaken in restricted geographic areas. They are often based on specific demographic subgroups (eg, children) or are derived from treatment data (eg, GP consultations). Causal factors are seldom quantified in these reports. OBJECTIVE: This study was designed to quantify the prevalence of allergic disease among a representative cross-section of population in the United Kingdom. It was also designed to quantify the reported causal factors in terms of domestic allergen and irritant sources and activities leading to exposure. METHODS: Two thousand respondents were selected from across the UK. These respondents were interviewed using a short series of questions that formed part of a larger, more general omnibus questionnaire. The questions required respondents to report on diagnosed allergic disease and causal factors within their household, giving a total sample base of 5,609 people. RESULTS: Asthma and hay fever account for the majority of reported cases of allergic disease in the UK (12% and 10% of total household, respectively). Pollen, house dust mite excreta (HDM allergen), and pet dander are the three most common allergic triggers (42%, 27%, and 17% respectively). Dusting and being near pets each account for about 20% of the reported domestic activities triggering an allergic response. CONCLUSION: The feedback from the general population indicates asthma and hay fever to be the predominant allergic conditions, with dust and pet dander the most common sources of allergen/irritant. Key tasks such as changing bed linen and vacuuming were not perceived as being as important as dusting in terms of activities leading to reaction.     

Is the atopic march related to confounding by genetics and early‐life environment? A systematic review of sibship and twin data

A popular hypothesis known as the atopic march proposes a set of sequential allergy and respiratory disorders in early childhood contributes enormously to the burden of disease in developed countries. Although the concept of the atopic march has been refined and strengthened by many cross‐sectional and longitudinal studies linking eczema as the initial manifestation with progression to hay fever and then asthma, there is yet no definitive proof that the atopic march is the primary causal factor in childhood allergic disease. This debate is mainly related to the controversy around potential confounding of these associations by genetic and environmental factors. Family studies are ideally suited to unravelling the role of these factors. While multiple reviews have synthesized evidence from studies investigating this question, no review to date has explored specific evidence generated by twin and sibling studies to understand the aetiology of atopic march diseases. Our aim was to conduct a systematic review of twin and sibling studies that examine the allergic phenotypes that form the atopic march, to determine whether such analyses of data from these studies attempt to control for the effect confounding by shared factors, and to report estimates of the magnitude of associations between multiple phenotypes. Our review suggests that (1) genetics play a bigger role predisposing eczema to hay fever and eczema to asthma than environmental factors, and (2) the link between eczema and asthma and hay fever is independent of shared early‐life environmental factors.     

History of allergic diseases and lung cancer risk

BackgroundThe exact nature and direction of the association between a history of allergic diseases and lung cancer risk remain controversial.ObjectiveTo examine the association between self-reported history of allergic diseases and lung cancer using data from a population-based case–control study conducted in the Montreal metropolitan area (1996–2002).MethodsThe study is based on interview data collected from 1,169 incident lung cancer cases and 1,486 controls. Separate logistic regression models were used to estimate the relative risk of lung cancer, using odds ratios (ORs) and 95% confidence intervals (CIs), in subjects with vs without asthma, eczema, or hay fever after adjustment for several sociodemographic and lifestyle factors, including smoking.ResultsFor asthma, the OR was 0.90 (95% CI 0.65–1.24), which decreased to 0.76 (95% CI 0.54–1.08) for subjects whose onset was more than 2 years before lung cancer diagnosis or interview and then to 0.64 (95% CI 0.44–0.93) when restricted to subjects who reported using medication for their asthma. For eczema, the point estimate was 0.73 (95% CI 0.48–1.12), which decreased to 0.63 (95% CI 0.38–1.07) when considering eczema only in those who reported medication use. Hay fever showed the strongest inverse association with lung cancer (OR 0.37, 95% CI 0.24–0.59).ConclusionAll 3 allergic diseases examined were inversely associated with lung cancer, although the strength of the protective effect varied. History of allergic diseases seems to have a protective role in lung cancer incidence, after consideration of potential confounders, including lifetime smoking history.     

Time trends in prevalence and severity of childhood asthma and allergies from 1995 to 2002 in France

Objective:  To assess time trends in symptoms of asthma, allergic rhinitis and atopic eczema among adolescents in Languedoc Roussillon, France.
Methods:  Two cross-sectional surveys were conducted 7 years apart using the same protocol. School-based samples of 3383 participants in the 1995 survey and 1642 participants in the 2002 survey respectively were recruited.
Results:  There was a tendency towards stagnation in current symptoms of asthma, rhinoconjunctivitis and eczema. Indices related to lifetime diagnosis of asthma, hay fever and eczema increased. For all the conditions, indices of severity also showed a decrease in the 7-year study period.
Conclusions:  Our study shows that symptoms of asthma, allergic rhinitis and eczema were stable, supporting the effectiveness of national asthma prevention and management guidelines for such diseases. The increase in indices related to lifetime diagnosis could be the result of increased public and professional awareness of the diseases and changes in diagnostic labelling in recent years.