Predictors of allergen sensitization in Singapore children from birth to 3 years

Abstract

BackgroundImmune responses in allergic diseases begin with allergen sensitization, which usually occurs in childhood. Allergen sensitization involves a complex interplay of genetic and environmental factors, and sensitization patterns may change with age.ObjectiveTo determine the predictors of allergen sensitization in the first 3 years of life in the growing up in Singapore towards healthy outcomes (GUSTO) prospective birth cohort study.MethodsInterviewers collected information on demographics, family history of allergy, social and lifestyle factors, and the child’s health. We analyzed data from 849 children who completed skin prick testing (SPT) to inhalant allergens (house dust mites: Dermatophagoides pteronyssinus, Dermatophagoides farinae, and Blomia tropicalis) and food allergens (egg, peanut and cow’s milk) to assess risk factors for allergen sensitization at 18 months. To ensure that clinical phenotypes preceded allergen sensitization, we also analyzed data from 649 children who had a negative skin prick test at 18 months and completed skin prick testing at 36 months.ResultsWe observed a significant association between eczema reported before 18 months and a positive SPT at 18 months [aOR 4.5 (1.9–10.7)]. Ninety-five (14.6 %) children with negative SPTs at 18 months developed positive tests at 36 months. Onset of eczema before 18 months was associated with an increased risk of new allergen sensitization at 36 months among children non-sensitized at 18 months [aOR 3.4 (1.2–9.3)]. An association was seen between wheeze reported before 18 months and new allergen sensitization at 36 months [aOR 3.2 (1.1–9.1)]. We found no significant association, however, between rhinitis reported before 18 months and new allergen sensitization at 36 months.ConclusionsEarly onset of eczema and wheeze are risk factors for later allergen sensitization, suggesting a possible increased susceptibility to allergen exposure through an impaired skin barrier or defective airway epithelium. Trial registration NCT01174875 Registered 1 July 2010, retrospectively registered

Patterns of allergic sensitization and atopic dermatitis from 1 to 3 years: Effects on allergic diseases

“…Similarly, Matricardi and colleagues found in the Multi‐centre Allergy Study (MAS) that AD occurring before age 2 years in association with wheezing before age 3 years gave a positive predictive value of 41.4 for wheezing in early adolescence . In the GUSTO cohort in Singapore, AD occurring before 18 months of age was associated with a threefold increased risk of new allergic sensitization; a similar threefold increase in risk of new sensitization was found for wheeze before 18 months …”

“…11 The heterogeneity of methods used in past cross-sectional and cohort studies examining sensitization and AD as risk factors for allergic diseases makes interpretation difficult. Some examined only incident cases of AD, 12,13 others assessed the risk of AD among all children and some did not distinguish between different types of sensitization. 1,[12][13][14][15][16][17][18] Ignoring the heterogeneity in the type of allergic sensitization (food, inhalant, food and inhalant, mono-sensitization and poly-sensitization), time of manifestation (persistent or transient) and AD status by simply categorizing children as "atopic" and "non-atopic" may obscure differential impacts of these risk factors.…”

“…Some examined only incident cases of AD, 12,13 others assessed the risk of AD among all children and some did not distinguish between different types of sensitization. 1,[12][13][14][15][16][17][18] Ignoring the heterogeneity in the type of allergic sensitization (food, inhalant, food and inhalant, mono-sensitization and poly-sensitization), time of manifestation (persistent or transient) and AD status by simply categorizing children as "atopic" and "non-atopic" may obscure differential impacts of these risk factors. [6][7][8][9][10] For instance, an increased risk for hospitalizations due to asthma was only found among children who were poly-sensitized at an early age but not among those sensitized at a later age.…”

Cause and Clinical Presentation of Anaphylaxis in Singapore: From Infancy to Old Age

“…In Singapore, the prevalence of HDM sensitisation is high and increases with age. HDM sensitisation increased from 11% at 18 months to 23% at 36 months in a prospective birth cohort study of healthy children [30], to 91% in a population of clinically atopic children with mean age of 7.3 years [31]. In a study of HDM sensitisation among mainland Chinese migrants, prevalence was low in migrants who had recently arrived in Singapore, and increased to 50% in migrants who had spent more than 8 years in Singapore [32].…”

Diagnosing atopic dermatitis in infancy: Questionnaire reports vs criteria‐based assessment

“…A child was classified to have AD by this measure if parents indicated a physician diagnosis of eczema/atopic dermatitis. Children who had not consulted a physician for a rash, or reported no rash, were coded to have no AD diagnosis from an external physician …”