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The prevalence of allergic rhinitis (AR) among children has increased markedly in Beijing during the last two decades. The purpose of this study was to estimate the prevalence of AR and to identify indoor risk factors for AR among preschool children. A cross-sectional questionnaire survey was conducted in Beijing, 2011. Parents of 5388 3–6 years old children (65% response rate) from randomly selected kindergartens in Beijing participated in this study. A Chi-square test and multiple logistic regressions were used to identify risk factors. Our survey found that the prevalences of “AR symptoms ever,” “AR symptoms current” (AR symptoms in the last 12 months) and “doctor-diagnosed AR” are 49.5%, 45.6% and 7.8%, respectively. Confounding factors for “AR symptoms” and/or “doctor-diagnosed AR” are gender, age, family allergic history, breastfeeding and current environmental tobacco smoke (ETS). New furniture, condensation on window pane and cockroaches are risk factors for both “AR symptoms ever” and “AR symptoms current”. Risk factors for “AR symptoms ever” include the use of humidifier and incense. A risk factor for “AR symptoms current” is mosquitoes/flies. Risk factors for “doctor-diagnosed AR” include living close to a main road or highway, visible mold spots and current pet keeping. A protective factor against doctor-diagnosed AR is opening the child's bedroom window in winter (aOR 0.66, 95% CI 0.48, 0.92). We found that the greater the number of home environmental risk factors, the higher risk of AR. A number of home environmental factors are associated with AR among preschool children. [ABSTRACT FROM AUTHOR]

Background: The prevalence of asthma among Shanghai children has increased over time. This increase might be associated with changes in environmental exposures. Investigation of the time-trend of asthma and current prevalences is essential to understanding the causes. Objective: To estimate the current prevalences of asthma, allergies and other respiratory symptoms among Shanghai preschool children, and to investigate the time-trend of childhood asthma prevalence of from 1990 to 2011. Methods: From April 2011 to April 2012, the CCHH (China, Children, Homes, Health) cross-sectional study was conducted in Shanghai. Questionnaires were distributed to 17,898 parents or guardians of preschool children from 72 kindergartens in 5 districts. Previous similar studies were also summarized by a systematic literature review. Results: From a total of 14,884 questionnaires for 3–7 year old children, prevalences of the following diseases and symptoms were calculated: asthma 10.2%, wheeze (ever) 28.1%, pneumonia (ever) 33.5%, otitis media 11.0%, rhinitis (ever) 54.1%, hay fever 12.2%, eczema (ever) 22.7%, and food allergy 15.7%. Urban children had higher prevalences of most symptoms than suburban children. The prevalence of asthma has increased significantly, almost five-fold, from 2.1% in 1990 to 10.2% in the present study. The prevalence of asthma in boys was higher than in girls in the present study and in all reviewed studies. Conclusions: Asthma, allergy and airway symptoms are common among preschool children in Shanghai. The prevalence of childhood asthma in Shanghai has increased rapidly from 1990 to 2011. [ABSTRACT FROM AUTHOR]

This study evaluated the prevalence and risk factors for asthma, allergy and related symptoms; and breastfeeding patterns and durations for 5479 Beijing children aged 3–6. Parents of children in randomly selected kindergartens wrote responses to a questionnaire used previously. The study aimed to evaluate trends in the prevalence of asthma and related illnesses, and to determine whether “more” breastfeeding, defined as exclusive, > 6 months, was associated with reduced prevalence. Asthma has increased in this age group between 1990 and 2011, with the steepest increase in the last 2–3 years. Of the total, 14.2% (779) children were breastfed exclusively for > 6 months. The efficacy of “more” breastfeeding was tested in a subset with two strong risk factors, positive family history (for asthma and/or allergy) and male gender. “More” breastfeeding was found to be significantly protective (aOR 0.42, P < 0.05) for this subset against Doctor-diagnosed asthma (D-asthma). Protection that did not reach statistical significance was also found for this subset against Wheeze ever, Cough at night, Rhinitis ever, Doctor-diagnosed rhinitis (D-rhinitis) and Eczema. The greatest protective effects were found for girls with no family history of asthma or allergy, reaching statistical significance for Wheeze ever (aOR 0.48, P < 0.01), Cough at night (aOR 0.47, P < 0.01), D-asthma (aOR 0.14, P < 0.01) and Rhinitis ever (aOR 0.67, P < 0.05). “More” breastfeeding was not consistently associated with either a protective or risk effect for Eczema. [ABSTRACT FROM AUTHOR]