The prevalence and socio-demographic risk factors of clinical eczema in infancy: a population-based observational study

Background Socio-demographic predictors for the development of clinically observed, infantile eczema have not been formally examined in a large population-based study. Few studies of eczema risk factors have included current, objective eczema outcomes as well as parent-reported history. Objectives We aimed to measure the population prevalence of infantile eczema using novel sampling methodology, and identify socio-demographic risk factors for eczema in the first year of life. Methods A population-based cross-sectional study of infantile allergy (the HealthNuts study, n=4972, response rate 74.1%) was conducted from 2008-2011 in Melbourne, Australia. Infants were examined for current eczema at age 12months (mean 12.7, SD 0.7). Parents provided information about the infants' history of eczema and demographic factors. Factors associated with eczema were modelled using multinomial logistic regression. Results The population prevalence of observed eczema at 12months was 20.3% (95% CI 19.0, 21.5), while cumulative prevalence for parent-reported eczema was 28.0% (95% CI 26.7, 29.4). The strongest predictors of eczema were maternal eczema and asthma (multinomial (M)-OR 1.7, P<0.001, and M-OR 1.4, P=0.007), male sex (M-OR 1.4, P<0.001), and East Asian ethnicity (M-OR 1.6, P<0.001) with over 80% of infants with all risk factors exhibiting eczema. East Asian parents, particularly recent migrants, reported fewer allergies than other parents. Conclusions and Clinical Relevance Approximately, one in three infants developed eczema by 12months of age. East Asian infants are at increased risk of eczema despite their parents having lower rates of allergy than non-Asian parents. Gene-environment interactions may explain the differential effect seen in this minority group.