Schema illustrating the recruitment process in this study. Children were matched for age, gender and ethnicity. Children were excluded from the study, if they had any chronic medical conditions such as known genetic syndromes, severe asthma or allergies, or if they were on any chronic medications.
Chatsuriyawong et al. BMC Medical Genomics 2013 6:29 doi:10.1186/1755-8794-6-29