Chronic childhood disorders: prevalence and impact.
D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D002908:Chronic Disease / Q000453:epidemiology*; D006801:Humans; D007223:Infant; D010372:Pediatrics; D011157:Population Dynamics; D011379:Prognosis; D014481:United States