Prevalence of Self-reported Allergic Diseases and IgE Levels: A 2010 KNHANES Analysis

PURPOSE: The prevalence of allergic diseases is known to be associated with both demographic and environmental factors. Herein, we aimed to determine significant factors associated with the prevalence of allergic diseases and with total immunoglobulin E (tIgE) and specific immunoglobulin E (sIgE) levels in Korea. METHODS: We analyzed unweighted data collected by the 2010 Korea National Health and Nutrition Examination Survey for 2,342 subjects who underwent serum tests for tIgE and sIgE to Dermatophagoides farinae, dog, and Blattella germanica, representing a sample of 16,003,645 citizens, by considering the sample weight and stratification. RESULTS: The overall prevalence of self-reported allergic diseases was 37.6%. The prevalence rates of allergic rhinitis and atopic dermatitis decreased with age, whereas the asthma prevalence was not affected by the age of the subjects. When analyzed according to the type of allergic diseases, the prevalence of self-reported allergic disease was significantly associated with various factors (e.g. age, occupation, living in urban areas, and depression). The tIgE level decreased with age, but later increased. Elevation of tIgE was significantly associated with male sex, type of occupation, obesity, and smoking status. However, the risk factors for the increased sIgE levels to each allergen were quite different. Sensitization to D. farinae was more likely in young subjects, whereas the prevalence of sensitization to B. germanica was significantly higher in subjects with male sex, residing in a house (houses), and with glucose intolerance. Finally, young age and the smoking status were significantly associated with sensitization to dog. CONCLUSIONS: Various demographic and environmental factors were significantly associated with the prevalence of self-reported allergic diseases and the levels of tIgE and sIgE to D. farinae, B. germanica, and dog in Korea.

Age-Related Changes in Immunological Factors and Their Relevance in Allergic Disease Development During Childhood

PURPOSE: Allergic diseases are triggered by Th2-mediated immune reactions to allergens and orchestrated by various immunological factors, including immune cells and cytokines. Although many reports have suggested that childhood is the critical period in the onset of allergic diseases and aging leads to alter the susceptibility of an individual to allergic diseases, age-related changes in various immunological factors in healthy individuals as well as their difference between healthy and allergic children have not yet been established. METHODS: We investigated the ratio of Th1/Th2 cells and the levels of 22 allergy-related cytokines across all age groups in individuals who were classified as clinically non-atopic and healthy. We also examined their differences between healthy and allergic children to evaluate immunological changes induced by the development of allergic diseases during childhood. RESULTS: The Th1/Th2 ratio rose gradually during the growth period including childhood, reaching peak values in the twenties-thirties age group. Th1/Th2 ratios were significantly lower in allergic children than in healthy controls, whereas 14 of 22 cytokines were significantly higher in allergic children than in healthy controls. On the other hand, there were no differences in Th1/Th2 ratios and cytokines between healthy and allergic adolescents. CONCLUSIONS: In this study, age-related changes in Th1/Th2 ratios were found in normal controls across all age groups, and decreases in Th1/Th2 ratio were observed with increasing of 14 cytokines in allergic children. The results of this study may be helpful as reference values for both monitoring immunological changes according to aging in healthy individuals and distinguishing between normal and allergic subjects in terms of immune cells and soluble factors.

Assessment of Total/Specific IgE Levels Against 7 Inhalant Allergens in Children Aged 3 to 6 Years in Seoul, Korea

PURPOSE: Childhood allergies are a serious problem, as they may lead to lifetime chronic disease. Determination of total and specific IgE levels is known to be a diagnostic tool for allergic sensitization; however, IgE levels are affected by various factors, such as age, sex, ethnicity, and geographic area. Thus, we evaluated the distribution of total and specific serum IgE levels against seven inhalant allergens in preschool children and examined their association with allergic diseases in Seoul, Korea. METHODS: Total/specific serum IgE determination and skin prick tests for seven common allergens were performed on 509 children aged 3 to 6 years from 16 child care centers in Seoul, Korea. Demographic characteristics were surveyed from parents using a modified International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire. A diagnosis of atopic dermatitis was made by physicians. RESULTS: The geometric mean of total IgE was 80.48+/-3.80 kU/L in preschool children. IgE levels were higher in boys (boys, 102.34+/-3.52 kU/L; girls, 62.37+/-3.93 kU/L; P<0.001) and atopic subjects (atopic, 158.00+/-3.35 kU/L; non-atopic, 52.75+/-3.44 kU/L; P<0.001). An increased prevalence of atopy was associated with a high monthly household income (P=0.004) and higher maternal education level (above university-level education; P=0.009), as well as increased total IgE levels (P=0.036). Physician-diagnosed atopic dermatitis was associated with sensitization to inhalant allergens. CONCLUSIONS: Total IgE levels were very high as compared with those in previous reports from other countries. The most common sensitized allergen was Dermatophagoides farinae, and the positive response rate peaked at age 3 years and was maintained thereafter, particularly in boys. Specific IgE levels for seven inhalant allergens varied with age in preschool children. Although further investigations are needed with a broad range of ages and various allergens, the distribution of the total and specific serum IgE levels in preschool children might help to serve as a reference value to diagnose atopy.

arrayImpute: Software for Exploratory Analysis and Imputation of Missing Values for Microarray Data

arrayImpute is a software for exploratory analysis of missing data and imputation of missing values in microarray data. It also provides a comparative analysis of the imputed values obtained from various imputation methods. Thus, it allows the users to choose an appropriate imputation method for microarray data. It is built on R and provides a user-friendly graphical interface. Therefore, the users can easily use arrayImpute to explore, estimate missing data, and compare imputation methods for further analysis.