Age-specific incidence of allergic and non-allergic asthma

BMC Pulm Med. 2020 Jan 10;20(1):9. doi: 10.1186/s12890-019-1040-2.

Abstract

Background: Onset of allergic asthma has a strong association with childhood but only a few studies have analyzed incidence of asthma from childhood to late adulthood in relation to allergy. The purpose of the study was to assess age-specific incidence of allergic and non-allergic asthma.

Methods: Questionnaires were sent to 8000 randomly selected recipients aged 20-69 years in Finland in 2016. The response rate was 52.3% (n = 4173). The questionnaire included questions on e.g. atopic status, asthma and age at asthma diagnosis. Asthma was classified allergic if also a physician-diagnosed allergic rhinitis was reported.

Results: The prevalence of physician-diagnosed asthma and allergic rhinitis were 11.2 and 17.8%, respectively. Of the 445 responders with physician-diagnosed asthma, 52% were classified as allergic and 48% as non-allergic. Median ages at diagnosis of allergic and non-allergic asthma were 19 and 35 years, respectively. Among subjects with asthma diagnosis at ages 0-9, 10-19, 20-29, 30-39, 40-49, 50-59 and 60-69 years, 70, 62, 58, 53, 38, 19 and 33%, respectively, were allergic. For non-allergic asthma, the incidence rate was lowest in children and young adults (0.7/1000/year). It increased after middle age and was highest in older age groups (2.4/1000/year in 50-59 years old).

Conclusions: The incidence of allergic asthma is highest in early childhood and steadily decreases with advancing age, while the incidence of non-allergic asthma is low until it peaks in late adulthood. After approximately 40 years of age, most of the new cases of asthma are non-allergic.

Keywords: Adolescent; Adult; Age-specific; Allergic; Asthma; Child; Incidence; Non-allergic; Onset; Prevalence.

MeSH terms

  • Adolescent
  • Adult
  • Age Distribution
  • Aged
  • Asthma / diagnosis
  • Asthma / epidemiology*
  • Child
  • Child, Preschool
  • Female
  • Finland / epidemiology
  • Humans
  • Incidence
  • Infant
  • Infant, Newborn
  • Male
  • Middle Aged
  • Prevalence
  • Rhinitis, Allergic / diagnosis
  • Rhinitis, Allergic / epidemiology*
  • Surveys and Questionnaires
  • Young Adult