Sibship size and prevalence of allergic disorders in Japan: The Ryukyus Child Health Study

A number of epidemiological studies have reported an inverse association between increasing sibship size and allergic disorders. The present cross-sectional study assessed the association between the number of siblings and the prevalence of allergic disorders during the past 12 months in Japanese schoolchildren. Study subjects were 22,750 children aged 6–15 yr in Okinawa. The outcomes were based on diagnostic criteria from the International Study of Asthma and Allergies in Childhood. Adjustment was made for age, gender, maternal age at childbirth, duration of breastfeeding, region of residence, smoking in the household, paternal and maternal history of asthma, atopic eczema, and allergic rhinitis, and paternal and maternal educational level. Significant exposure–response associations were observed between increasing total sibship size and all outcomes under investigation. Having two or more older siblings was significantly inversely related to the prevalence of atopic eczema and allergic rhinoconjunctivitis, but not wheeze or asthma. Having two or more younger siblings was independently associated with a decreased prevalence of atopic eczema, but not wheeze, asthma, or allergic rhinoconjunctivitis. The inverse relationships between sibship size and the prevalence of allergic disorders under study were weakened with advancing age, although the interactions between age groups were not statistically significant. No significant interactions were found in the association of having three or more siblings with allergic disorders between children with a positive or negative parental allergic history. These results are likely to support the in utero programming hypothesis because it is probable that the in utero environment would change with parity, although our observations could not refute the hygiene hypothesis.     

Breastfeeding and atopic eczema in Japanese infants: The Osaka Maternal and Child Health Study

Epidemiological studies associated with breastfeeding have provided conflicting results about whether it is preventive or a risk factor for atopic eczema in children. The current prospective study investigated the relationship between breastfeeding and the risk of atopic eczema in Japan. A birth cohort of 763 infants was followed. The first survey during pregnancy and the second survey between 2 and 9 months postpartum collected information on potential confounding factors and atopic eczema status. Data on breastfeeding and symptoms of atopic eczema were obtained from questionnaires in the third survey from 16 to 24 months postpartum. The following variables were a priori selected as potential confounders: maternal age, maternal and paternal history of asthma, atopic eczema, and allergic rhinitis, indoor domestic pets (cats, dogs, birds, or hamsters), family income, maternal and paternal education, maternal smoking during pregnancy, baby’s sex, baby’s birth weight, baby’s older siblings, household smoking in the same room as the infant, and time of delivery before the third survey. In the third survey, 142 infants (18.6%) were revealed to have developed atopic eczema based on criteria of the International Study of Asthma and Allergies in Childhood. In an overall analysis, neither exclusive nor partial breastfeeding was significantly related to the risk of atopic eczema. After excluding 64 infants identified with suspected atopic eczema in the second survey, both exclusive breastfeeding for 4 months or more and partial breastfeeding for 6 months or more were independently associated with an increased risk of atopic eczema only among infants with no parental history of allergic disorders [multivariate odds ratios were 2.41 (95% confidence interval, 1.10–5.55) and 3.39 (95% confidence interval, 1.20–12.36), respectively]. The authors found that, overall, neither exclusive nor partial breastfeeding had a strong impact on the risk of atopic eczema. However, a parental allergic history may affect the risk.     

Breastfeeding and the risk of wheeze and asthma in Japanese infants: The Osaka Maternal and Child Health Study

Epidemiological evidence for an effect of breastfeeding on asthma continues to be inconclusive. The present prospective study examined the relationship between breastfeeding and the risk of wheeze and asthma in Japanese infants. A birth cohort of 763 infants was followed. The first survey during pregnancy and the second survey between 2 and 9 months postpartum collected information on potential confounding factors. Data on breastfeeding, wheeze, and asthma were obtained from questionnaires in the third survey from 16 to 24 months postpartum. Adjustment was made for maternal age, maternal and paternal history of asthma, atopic eczema, and allergic rhinitis, indoor domestic pets (cats, dogs, birds, or hamsters), family income, maternal and paternal education, maternal smoking during pregnancy, baby's sex, baby's older siblings, household smoking in the same room as the infant, and time of delivery before the third survey. By the third survey, the cumulative incidence of wheeze and asthma was 22.1% and 4.3%, respectively. Neither exclusive breastfeeding for 4 months or more nor partial breastfeeding for 6 months or more were materially related to the risk of wheeze. No measurable association was observed between exclusive breastfeeding for 4 months or more and the risk of asthma. Partial breastfeeding for 6 months or more was inversely related to the risk of asthma although the adjusted odds ratio (OR) was not statistically significant. When infants were stratified according to whether there was a negative or positive allergic history in at least 1 parent, a nearly 40% and 60% decrease, respectively, in the ORs were found for exclusive and partial breastfeeding only in infants without a parental allergic history, although the ORs were not statistically significant. The present prospective study showed no statistically significant relationship between breastfeeding duration and the risk of wheeze or asthma in Japanese infants.     

Cross-sectional study of allergic disorders in relation to familial factors in Japanese adolescents

AIM: The roles of heredity and the household environment in the development of allergic disorders are not clearly established. This study examined the relationship between selected familial factors and the prevalence of symptoms of wheeze, atopic eczema and rhinoconjunctivitis in Japanese adolescents. METHODS: Study subjects were 5539 students aged 12-15 y in Suita City. A questionnaire ascertained gender, grade, number of older siblings, maternal age at childbirth, smoking in the household, domestic pets and parental history of allergy, as well as signs and symptoms of allergy in the previous 12 mo. The latter were based on diagnostic criteria from the International Study of Asthma and Allergies in Childhood. RESULTS: Male gender was independently associated with an increased prevalence of wheeze and a decreased prevalence of atopic eczema. The prevalence of rhinoconjunctivitis, but not wheeze or atopic dermatitis, significantly increased with advancing grade. A significant inverse dose-response relationship between the number of older siblings and the prevalence of rhinoconjunctivitis, but not wheeze or atopic dermatitis, was observed. Maternal age at childbirth, smoking in the household and domestic pets were not apparently related to any of the allergic disorders. A positive maternal allergic history was more evidently associated with an increased prevalence of wheeze and rhinoconjunctivitis, but not atopic eczema, than a positive paternal allergic history. CONCLUSION: The findings suggest that the factors associated with allergic disorders in Japan are largely the same as those already identified in Western populations.     

Home environment and suspected atopic eczema in Japanese infants: The Osaka Maternal and Child Health Study

Atopic eczema is most commonly diagnosed in children under the age of 5 yr. Environmental factors during pregnancy or in early life may confer risk for childhood atopic eczema. The present prospective study examined the relationship of the perinatal home environment and the risk of suspected atopic eczema among Japanese infants under the age of 1. Study subjects were 865 parent-child pairs. The term 'suspected atopic eczema' was used to define an outcome based on our questionnaire at 2-9 months postpartum. Adjustment was made for maternal age, gestation, family income, maternal and paternal education, maternal and paternal history of asthma, atopic eczema, and allergic rhinitis, time of delivery before the second survey, baby's older siblings, baby's sex, and baby's birth weight. A high mite allergen level from maternal bedclothes and mold in the kitchen during pregnancy were significantly associated with an increased risk of suspected atopic eczema. Frequent vacuuming practices during pregnancy and giving the infant a bath or shower at least once a day were significantly inversely related to the risk of suspected atopic eczema. Maternal smoking, maternal use of a synthetic duvet and pillow, carpet use in the living room and maternal bedroom, indoor domestic pets, no ducted heating appliance, and gas use for cooking during pregnancy and household smoking in the same room as the infant, infant's synthetic duvet, carpet use in the infant's room, or vacuuming the infant's room were not related to the risk of suspected atopic eczema. High house dust mite allergen levels and mold in the kitchen during pregnancy may increase the risk of infantile atopic eczema, whereas frequent vacuuming practices during pregnancy and giving the infant a bath or shower at least once a day may protect against infantile atopic eczema.     

Disparate geographic prevalences of asthma,allergic rhinoconjunctivitis and atopic eczema among adolescents in five Canadian cities

Wang H‐Y, Pizzichini MMM, Becker AB, Duncan JM, Ferguson AC, Greene JM, Rennie DC, Senthilselvan A, Taylor BW, Sears MR. Disparate geographic prevalences of asthma, allergic rhinoconjunctivitis and atopic eczema among adolescents in five Canadian cities.
Pediatr Allergy Immunol 2010: 21: 867–877.
© 2010 John Wiley & Sons A/S To assess concordance of prevalence rates of asthma, allergic rhinoconjunctivitis and atopic eczema symptoms among adolescents in five Canadian cities. The International Study of Asthma and Allergies in Childhood Phase 3 written questionnaires were answered by 8334 adolescents aged 13 to 14 in Vancouver, Saskatoon, Winnipeg, Hamilton and Halifax, Canada. Prevalence rates of current symptoms ranged from 13.7–33.0% for wheezing, 14.6–22.6% for allergic rhinoconjunctivitis and 8.2–10.4% for atopic eczema. Using Hamilton as reference, the prevalence of wheezing was significantly higher in Halifax (OR = 1.58; 95% CI 1.36–1.84) and Saskatoon (1.27; 1.07–1.50) and significantly lower in Vancouver (0.51; 0.44–0.59). In contrast, allergic rhinoconjunctivitis was significantly more prevalent in Winnipeg (1.39; 1.16–1.68) and Halifax (1.36; 1.14–1.61) and trended lower in Saskatoon (0.81; 0.66–1.00). Atopic eczema was significantly more prevalent in Winnipeg (1.31; 1.01–1.69) and Vancouver (1.28; 1.04–1.58). Multivariable logistic regression analyses showed the region of residence, being born in Canada, recent use of acetaminophen and heavy exposure to traffic exhaust were significantly associated with all three allergic conditions, while obesity and having two or more smokers at home was only associated with increased risk for wheezing. Chinese ethnicity decreased that risk. Among five Canadian centres, the highest prevalence rates of allergic rhinoconjunctivitis or atopic eczema were not observed in the same regions as the highest prevalence rates of wheezing. This disparity in regional variations in the prevalence rates suggests dissimilar risk factors for the development or expression of wheezing (asthma), allergic rhinoconjunctivitis and atopic eczema.     

Time trends of the prevalence of asthma and allergic disease in Austrian children

After a substantial increase in the prevalence of atopic disease in Europe, recent studies indicate that a plateau has been reached. However, variation across countries and age groups exists. We studied the prevalence and time trends of asthma and allergic disease among schoolchildren in Austria, a country with traditionally low rates of asthma, hay fever, and eczema. As part of the International Study of Asthma and Allergies in Childhood (ISAAC), symptoms and physician diagnoses of asthma and allergic disease of 13,399 Austrian children aged 6–7 yr and 1516 children aged 12–14 yr were surveyed between 1995 and 1997. A similar survey was conducted between 2001 and 2003. Among children aged 6–7 yr, significant increases were seen in the prevalence of physician-diagnosed asthma (+16%; p = 0.013), hay fever (+22%; p < 0.001), and eczema (+37%; p < 0.001) between 1995 and 2003. These changes were paralleled by an increase in the prevalence of symptoms typical for hay fever (itchy eyes and runny nose), but not by an increase in wheeze. Among children aged 12–14 yr, the lifetime prevalence of diagnosed asthma increased by 32%, of hay fever by 19%, and of eczema by 28% (all, p < 0.001). These changes were paralleled by increases in the prevalence of wheezing as documented by both questions before and after a video showing wheezing children but not by symptoms typical for hay fever such as itchy eyes and runny nose. In conclusion, in Austria, contrary to other European countries, the prevalence of asthma and allergic disease increased among schoolchildren. Additional studies are needed to continue monitoring the dynamics of the prevalence of asthma and allergic disease in Austria and to explore trends in their risk factors.     

Margarine and butter consumption, eczema and allergic sensitization in children. The LISA birth cohort study

It has been hypothesized that margarine intake is associated with allergic diseases. However, the epidemiological evidence in children is limited. The aim of the present study was to assess the relationship between dietary intake of margarine and butter with eczema and allergic sensitization in 2-yr-old children. Data of 2582 children at the age of 2 yr with complete information on exposure to diet and allergic outcome were analyzed in a German prospective birth cohort study (LISA). Margarine and butter intake were estimated from a semiquantitative food frequency questionnaire about general fat use at home combined with questions on the child's spread intake. Multiple logistic regression analysis was applied comparing predominant margarine and predominant butter intake with consumption of both butter and margarine. Predominant margarine intake was positively associated with lifetime prevalence of symptomatic eczema (aOR: 1.71; 95% CI: 1.12-2.61) and doctor-diagnosed eczema (aOR: 2.10; 95% CI: 1.36-3.25) and allergic sensitization against inhalant allergens (aOR: 2.10; 95% CI: 1.01-4.41) at the age of 2 yr. No statistically significant associations were found for butter intake. Stratification for parental history of atopic diseases indicated that children at high risk of atopic diseases have higher effect estimates for margarine intake compared to children without parental history of atopic diseases. Stratification for sex also showed higher effect estimates in boys. Children with predominant margarine consumption had an increased risk for eczema and allergic sensitization, while butter intake was no predictor for allergic diseases. However, we could not determine whether margarine is a causal risk factor or whether other lifestyle factors have influenced this association.     

Current cat ownership may be associated with the lower prevalence of atopic dermatitis, allergic rhinitis, and Japanese cedar pollinosis in schoolchildren in Himeji, Japan

The aim of the study was to clarify the relationship between current pet ownership, passive smoking, and allergic diseases among the Japanese children. From 1995 to 2001, we distributed the Japanese edition of the questionnaire of the American Thoracic Society and the Division of Lung Diseases (ATS-DLD) to survey allergic diseases among 35,552 6-yr-old children at primary school in the city of Himeji, Japan. We analyzed the data by multiple logistic regression and calculated adjusted odds ratios for environmental factors, including passive smoking and pet (dog and/or cat) ownership. There were no significant relationships between the prevalence of asthma and current pet ownership and passive smoking. However, current cat ownership was related to a significantly lower prevalence of atopic dermatitis [adjusted odds ratio (aOR) 0.79, 95% confidence interval (CI) 0.67-0.93], allergic rhinitis (aOR: 0.71, 95% CI 0.57-0.89) and Japanese cedar pollinosis (aOR 0.57, 95% CI 0.44-0.75). Strikingly, passive smoking was also related to a significantly lower prevalence of allergic rhinitis (aOR 0.83, 95% CI 0.77-0.89) and Japanese cedar pollinosis (aOR 0.81, 95% CI 0.74-0.88). Current cat ownership was associated with a lower prevalence of atopic dermatitis, allergic rhinitis, and Japanese cedar pollinosis. In addition, passive smoking was also associated with a lower prevalence of allergic rhinitis and Japanese cedar pollinosis.     

Allergy march of Chinese children with infantile allergic symptoms: a prospective multi-center study

Background:Allergy march refers to progression of allergic diseases from infantile food allergy to the development of asthma and allergic rhinitis (AR).Evidence come mostly from studies in European countries.This study aimed to investigate allergy march in Chinese children with infantile food protein allergy (FPA) with a special focus on the effect of different formula interventions.Methods:From 2008 to 2010,153 infants diagnosed with FPA were recruited in five tertiary hospitals across China.They were randomly treated with amino-acid-based formula or soy-protein-based formula for a period of 3 months.Long-term follow-up was performed when they reached early school age,using questionnaires,physical examinations,and serum-specific immunoglobulin E.Results:The overall follow-up rate was 73.20％.In patients who reached their early school years,the prevalence of physician-diagnosed AR and asthma were 43.75％ and 23.21％,respectively.Only 40％ of the subjects remained positive for food sensitizations upon follow-up.Twenty-six subjects receiving aeroallergen screening tests in infancy all proved negative,but upon follow-up,65.57％ were sensitized to aeroallergens (P=0.005).No significant difference between the effects of amino-acid-based formula and soy-protein-based formula on children's allergy march was observed.Conclusions:A high proportion (47.32％) of Chinese infants with early allergic symptoms developed respiratory allergies by their early school years.Most food-sensitized infants outgrew their condition several years later,but then aeroallergen sensitization often occurred.Amino-acid-based formula showed no advantages over soy protein-based formula with respect to arresting the allergy march.     

The prevalence of allergic diseases in an unselected group of 6-year-old children. The DARC birth cohort study

This study determines the prevalence of atopic dermatitis, asthma, rhinoconjunctivitis, food hypersensitivity and urticaria and the frequency of sensitization in children with and without clinical allergic disease. In an ongoing prospective non-interventional birth cohort study of 562 unselected children, 404 children were subjected to interview, clinical examination, lung function measurements and allergy testing at 6 yr of age. Sensitization measured by skin prick test (SPT) and specific immunoglobulin E (S-IgE) was determined for 24 different allergens. The 1-yr period prevalence of atopic dermatitis, asthma and rhinoconjunctivitis was 14.4%, 6.2% and 13.6%. 25.7% of the children suffered from at least one of the three diseases. The frequency of sensitization in children with no disease (controls), any allergic disease, atopic dermatitis, asthma and rhinoconjunctivitis was 17%, 45%, 47%, 56% and 55% (defined as SPT ≥3 mm and/or S-IgE ≥0.35 kU/l for at least one allergen). Symptoms were linked to sensitization for 44% in the asthma group and 42% in the rhinoconjunctivitis group, whereas sensitization could not be linked to worsening of the eczema in any cases of atopic dermatitis. Overlap between the three diseases was significantly more frequent in sensitized children than in non-sensitized (19/46 = 41% vs. 9/58 = 16%, p = 0.004). The prevalence of food hypersensitivity and urticaria was 1.2% and 5.4% respectively. In unselected 6 yr old children, approximately half of the children with atopic dermatitis, asthma or rhinoconjunctivitis are IgE-sensitized. Sensitization tends to link these diseases to each other.     

Increasing prevalence of allergic rhinitis but not asthma among children in Hong Kong from 1995 to 2001 (Phase 3 International Study of Asthma and Allergies in Childhood)

There is a worldwide belief that the prevalence of asthma and other allergic diseases is increasing but the measures used in many studies are susceptible to systematic errors. We examined the trend of asthma, allergic rhinitis and eczema prevalence in school children aged 6–7 years in Hong Kong from 1995 to 2001 using standardized ISAAC methodology. There were 4448 and 3618 children participating in 2001 and 1995, respectively. The prevalence of life-time rhinitis (42.4% vs. 38.9%, p < 0.01), current rhinitis (37.4% vs. 35.1%, p < 0.03), current rhinoconjunctivitis (17.2 vs. 13.6%, p < 0.01) and life-time eczema (30.7% vs. 28.1%, p = 0.01) increased significantly. There was no significant change in prevalence of life-time asthma, life-time wheeze and current wheeze albeit a significant increase in severe asthma symptoms. We investigated a number of potential risk factors including sex, family history of atopy, sibship size, birth weight, respiratory tract infections, pet ownership and exposure to tobacco smoke. However, the increases in prevalence of rhinitis and eczema could not be entirely explained by the change of prevalence of these risk factors. The odds ratio OR for the study period remained significantly associated with current rhinitis (OR 1.31, 95% confidence intervals CI 1.17–1.46), current rhinoconjunctivitis (OR 1.63, 95% CI 1.41–1.87) and life-time eczema (OR 1.30, 95% CI 1.16–1.45) after adjustment for these confounding variables using logistic regression model. Further study is warranted to elucidate the factors contributing to the observable change in the prevalence of rhinitis in our population.