title: Age at asthma onset and subsequent asthma outcomes among adults with active asthma.
abstract: BACKGROUND
  Little is known about the extent to which the age at which asthma first began influences respiratory health later in life. We conducted these analyses to examine the relationship between age at asthma onset and subsequent asthma-related outcomes.
  
  
  METHODS
  We used data from 12,216 adults with asthma who participated in the 2010 Behavioral Risk Factor Surveillance System Asthma Call-back Survey to describe the distribution of age at asthma onset. Linear regression was used to estimate associations of age at asthma onset with asthma-related outcomes, including symptoms in the past 30 days and asthma-related emergency visits.
  
  
  RESULTS
  Asthma onset before age 16 was reported by an estimated 42% of adults with active asthma, including 14% with onset at 5-9 years of age who reported experiencing any asthma symptoms on 21% of days in the past month. Compared to this group, the percentage of days in the past month with any asthma symptoms was 14.8% higher (95% confidence interval (CI): 5.4, 24.1) among those whose asthma onset occurred at <1 year. When age at onset occurred at 10 years or older there was little change in the prevalence of asthma-related emergency visits across age at onset categories.
  
  
  CONCLUSIONS
  Age at asthma onset may affect subsequent asthma-related outcomes.
authors.affiliation: Air Pollution and Respiratory Health Branch, Division of Environmental Hazards and Health Effects, National Center for Environmental Health, Centers for Disease Control and Prevention, 4770 Buford Highway NE, Mailstop F-60, Atlanta, GA 30341, USA. Electronic address: zif7@cdc.gov.
authors.forename: Maria C
authors.initials: MC
authors.lastname: Mirabelli
authors.forename: Suzanne F
authors.initials: SF
authors.lastname: Beavers
authors.forename: Arjun B
authors.initials: AB
authors.lastname: Chatterjee
authors.forename: Jeanne E
authors.initials: JE
authors.lastname: Moorman
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D017668:Age of Onset; D000368:Aged; D000369:Aged, 80 and over; D001249:Asthma / Q000150:complications / Q000453:epidemiology*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006306:Health Surveys; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D011379:Prognosis; D011647:Puerto Rico / Q000453:epidemiology; D014481:United States / Q000453:epidemiology; D055815:Young Adult
keywords: Asthma; Epidemiology; Prevalence; Respiratory health; Surveillance