Prevalence of childhood asthma over 40 years in Greece: is the changing
trend a result of diagnostic fashion?
Background: A series of repeated questionnaire surveys among 8- and
9-year-old schoolchildren in the city of Patras, Greece, demonstrated a
continuous rise in the prevalence of wheeze/asthma from 1978 to 2003,
with a plateau between 2003 and 2008. We further investigated
wheeze/asthma trends within the same environment during the last decade.
Methods: Two further identical cross-sectional surveys were conducted in
2013 (N=2554) and 2018 (N=2648). Physician-diagnosed wheeze and asthma
were analysed separately and in relation to their occurrence
(recent-onset: solely within the last two years; non-current: prior to
the last two years; persistent: both before and within the last two
years). In addition, in 2018, spirometry was performed in participants
reporting relevant symptoms and in a random sample of healthy controls.
Results: The prevalence of current wheeze/asthma declined from 6.9% in
2008 to 5.2% in 2013 and 4.3% in 2018. The persistent and non-current
wheeze/asthma groups (both including children with symptoms at preschool
age) followed this overall trend, while the prevalence of recent-onset
wheeze/asthma remained unchanged. Persistent and non-current wheezers
were also more frequently diagnosed with asthma, in contrast to those
with recent-onset wheeze. Children with recent-onset wheeze/asthma and a
considerable fraction of those with persistent symptoms had lower lung
function. Conclusions: The prevalence of childhood wheeze/asthma has
declined significantly during the last decade in Greece. Our analysis
suggests that the reversing trend is most likely attributed to changing
asthma perceptions among physicians and/or parents, especially in the
case of preschool children with troublesome respiratory symptoms.