Inclusion and exclusion criteria

Inclusion criteria
 Studies using any type of epidemiological design addressing the association between the prevalence rates of asthma and/or allergies and SEP
Exclusion criteria
  Mixed sample of children and adults if results were not presented separately
  Assessed biological aetiology of asthma or allergies (genomics, proteomics, transcriptomics or metabolomics)
  Assessed severity, treatment or access to services of asthma or allergies
 Type of articles
  Experimental studies
  Genetic analysis
  • SEP: socioeconomic position.