8 consecutive birth cohorts of children (1993-2000) were observed using the universal health insurance plan in Ontario, Canada.
The records of 1,059,511 children were examined, of whom 19% developed asthma in the first 8 years of life. Mean age at asthma diagnosis decreased from 4.7 years in birth year 1993 to 2.6 years in birth year 2000.
This study demonstrates an increase in asthma incidence and a decrease in the age of asthma diagnosis across multiple birth cohorts.
Trends in the age of diagnosis of childhood asthma. J Allergy Clin Immunol. 2014 Jun 27. pii: S0091-6749(14)00671-X. doi: 10.1016/j.jaci.2014.05.012. [Epub ahead of print]