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Kusunoki T, Morimoto T, Nishikomori R, Yasumi T, Heike T, Mukaida K, Fujii T, Nakahata T. Breastfeeding and the prevalence of allergic diseases in schoolchildren: Does reverse causation matter? Pediatr Allergy Immunol 2010: 21: 60–66. © 2010 John Wiley & Sons A/S Infants at higher risk of allergic diseases might be breastfed for longer periods compared with infants at lower risk in the hope that breastfeeding might reduce the risk of atopic disorders. Therefore, this intention could manifest as an apparent allergy-promoting effect of breastfeeding or reverse causation. To analyze the effect of breast feeding on the prevalence of allergic diseases at school age, a large questionnaire survey was administered to the parents of schoolchildren aged 7–15 yrs. 13,215 parents responded (response rate, 90.1%). Prevalence rates of allergic diseases were compared according to the type of feeding in infancy (either complete breastfeeding, mixed feeding or complete artificial feeding). In both univariate and multivariate analysis, compared with those with complete artificial feeding, those with mixed and complete breastfeeding showed a significantly lower prevalence of bronchial asthma (BA) (p = 0.01 and 0.003, respectively). On the other hand, in univariate analysis, the prevalence of atopic dermatitis (AD) and food allergy (FA) were significantly higher in those with complete breastfeeding (p = 0.04 and 0.01, respectively). There was a significantly higher proportion of complete breastfeeding among those with greater risk of allergic diseases (presence of family history, either eczema or wheeze within 6 months after birth, or FA in infancy). Therefore, our multivariate analysis included these risks as confounding factors, and we found that the promoting effects of breastfeeding on AD and FA disappeared. In conclusion, our data clearly showed the inhibitory effect of breastfeeding on the prevalence of BA at school age. The apparent promoting effect of breastfeeding on the prevalence of AD and FA is most likely because of reverse causation. [ABSTRACT FROM AUTHOR]

Although children allergic to eggs, milk or wheat in infancy tend to become tolerant by school age, the allergic status of these children at school age has not been well evaluated. To investigate the allergic status of schoolchildren who avoided eggs, milk or wheat because of an immediate-type allergic reaction at <1-yr-old (food avoiders in infancy), we conducted a large-scale questionnaire-based survey of schoolchildren. A questionnaire on allergic diseases was distributed to the parents of 14,669 schoolchildren aged 7 to 15 yr in 30 schools in Kyoto, Japan. Of these, 13,215 responded (response rate, 90.1%). The rate of 7-yr-old children who were food avoiders in infancy was 5.4%. This rate decreased as the current age of the children increased, down to 3% in 15-yr-old children, indicating that food allergy in infancy tended to become more prevalent over the past 8 yr. Although more than 80% became tolerant to these foods by school age, the prevalence of bronchial asthma, atopic dermatitis, allergic rhinitis and allergic conjunctivitis were significantly higher in this group. Moreover, avoidance of other foods (buckwheat, shellfish, fruits and others) at school age was seen at much higher frequencies than in non-food avoiders in infancy (adjusted odds ratio, 7.7; confidence interval, 5.9–10.2). This risk did not differ significantly between those who did and did not develop tolerance to eggs, milk and wheat by 3 yr old. In conclusion, food avoiders in infancy appear to have a higher risk of not only other allergic diseases (‘atopic march’) but also allergy to other foods (‘food allergen march’) at school age, indicating the need for continuous attention to food allergy. [ABSTRACT FROM AUTHOR]

Although the association between obesity and bronchial asthma (BA) has been gaining more attention, few studies have been conducted concerning the relationship between obesity and other allergic diseases. The objective of this study was to determine whether and how childhood obesity is associated with allergic diseases other than BA, such as atopic dermatitis (AD), allergic rhinitis (AR), allergic conjunctivitis (AC), and either AR or AC (AR/AC). A questionnaire was administered to the parents of 50,086 Japanese schoolchildren. Associations between childhood obesity and the various allergic diseases were evaluated by univariate and multivariate logistic models. Significant associations were found between higher body mass index (BMI) and AD (p = 0.03), and lower BMI and AC (p < 0.0001), and AR/AC (p < 0.0001). There was a significantly higher prevalence of BA in girls with obesity (p = 0.009) than in those without obesity. Significantly lower prevalence of AC (p = 0.01) and AR/AC (p = 0.002) among children with obesity, and AR (p = 0.04) and AR/AC (p = 0.0004) among boys with obesity were observed than those without obesity. Those who were obese and had AD were significantly more likely to have severe symptoms (p = 0.01). Overall, childhood obesity has positive associations with BA prevalence and AD severity, whereas it has negative associations with AR and AC prevalence, especially among boys. Changes in the immunologic balance accompanied by obesity might have different effects on each type of allergic disease. Exploring the mechanisms by which childhood obesity affects allergic status should lead to new management options for childhood allergy. [ABSTRACT FROM AUTHOR]

Background Previous studies have shown that dietary pattern is associated with allergy prevention. Methods We conducted a prospective cohort study on all primary schools in Omihachiman City, Shiga Prefecture, Japan. Questionnaires regarding allergic symptoms and diet were distributed to the parents of all 759 7-year-old schoolchildren for 4 consecutive years, from 2011 to 2014. Specific immunoglobulin E to inhalant allergens was measured at 10 years of age. Participants were then categorized as low, medium, or high intake during the study period for four food groups (fruits, vegetables, fish, and beans). Logistic regression analysis was performed to estimate odds ratios and 95% confidence intervals. Results A total of 520 children (68.5%) whose parents responded to the questionnaires all 4 years were included in the analysis. The prevalence of asthma, rhinitis, and any allergic symptoms at age 10 was significantly decreased with increases in fruit intake. In addition, the onset of any allergic symptoms during the study period was significantly decreased with increases in fruit intake (33.3%, 28.3%, and 14.3% in children with low, medium, and high fruit intake, respectively; P for trend =.01). The sensitization rate to ragweed at age 10 was significantly decreased with increases in fruit intake ( P for trend =.046). No significant effect was observed for the other three food groups, except for the association between fish intake and new-onset asthma symptoms. Conclusions These findings suggest that higher intake of fruit can help prevent respiratory allergic symptoms in schoolchildren. [ABSTRACT FROM AUTHOR]

Background To evaluate the association between sports activities and allergic symptoms, especially rhinitis, among schoolchildren. Methods This longitudinal survey of schoolchildren collected data from questionnaires regarding allergic symptoms based on the International Study of Asthma and Allergies in Childhood ( ISAAC) program and sports participation that were distributed to the parents of children at all 12 public primary schools in Ohmi-Hachiman City, Shiga Prefecture, Japan. Data were collected annually from 2011 until 2014, when the children reached 10 years of age. Blood samples were obtained in 2014, and the levels of immunoglobulin (Ig)E specific to four inhalant allergens were measured. Results Data from 558 children were analyzed. At 10 years of age, prevalence of asthma and eczema did not differ significantly, while rhinitis was significantly higher (p = 0.009) among children who participated in sports. Prevalence of rhinitis increased as the frequency or duration of sports participation increased (p < 0.01). The prevalence of new-onset rhinitis increased significantly among 10-year-olds with increasing duration of participation in sports (p = 0.03). Among those who participated in continuous sports activities, the prevalence of rhinitis was significantly higher with prolonged eczema (p = 0.006). Sports activities did not increase sensitization to inhalant allergens. Conclusion Sports activities enhance the prevalence of rhinitis in schoolchildren. Prolonged eczema, together with sports participation, further promotes the symptoms. The mechanisms of these novel findings warrant further investigation. [ABSTRACT FROM AUTHOR]

To cite this article: Kusunoki T, Mukaida K, Morimoto T, Sakuma M, Yasumi T, Nishikomori R, Heike T. Birth order effect on childhood food allergy. Pediatric Allergy Immunology 2012: 23: 250-254. Abstract Higher birth order is associated with a smaller risk of allergy (birth order effect). The purpose of this study was to compare the significance of the birth order effect on the prevalence of specific allergic diseases [bronchial asthma (BA), atopic dermatitis (AD), allergic rhinitis (AR), allergic conjunctivitis (AC), and food allergy (FA)] among schoolchildren. A questionnaire survey dealing with the prevalence of allergic diseases was administered to the parents of 14,669 schoolchildren aged 7-15 yr. Based on the data, the prevalence of each allergic disease was compared according to birth order (1st, 2nd, and 3rd or later). Multiple regression analysis was performed to test the significance of the differences. There was no significant difference in the prevalence of BA or AD according to birth order. The prevalence of AR, AC, and FA decreased significantly as birth order increased. The prevalence of FA among those with 1st, 2nd, and 3rd or later birth order was 4.0%, 3.4%, and 2.6%, respectively (p = 0.01). With respect to symptoms in infancy, the prevalence of wheeze increased significantly and that of FA and eczema in infancy decreased significantly as birth order increased. The present data show a significant birth order effect on FA. The effect was also observed for the prevalence of FA and eczema in infancy. These data support the concept of early, non-allergen-specific programming of IgE-mediated immunity. [ABSTRACT FROM AUTHOR]