Introduction
Ample evidence exists that there has been a dramatic increase in the
prevalence of childhood asthma through the 1980s and 1990s in
westernised countries. Many spoke of an ‘asthma epidemic’ and there has
been broad discussion on the underlying causes and the burden of the
disease on patients and society1-7. However, studies
conducted in the first two decades of the 21st century
suggested that asthma prevalence may have reached a plateau or even be
declining8-15. In the initial phase of the
International Study of Asthma and Allergies in Childhood (ISAAC I),
particularly high asthma rates were reported in English speaking
countries16. But in ISAAC III, 5-10 years later, these
countries showed a significant decline, despite the slight worldwide
increase in the prevalence of childhood asthma17. This
was also the case in a study based on 2001-2013 data from the
USA18 and in the Aberdeen surveys that cover a period
of 50 years (1964-2014)14,15. In contrast to the
‘asthma epidemic’, however, the reversing trend in the prevalence of
childhood asthma is difficult to explain12,15,18.
The Patras respiratory school surveys6,7,19, a series
of repeated questionnaire-based studies of 8-9-year-old schoolchildren
in the city of Patras, Greece, demonstrated a continuous rise in the
prevalence of wheeze/asthma from 1978 to 20036,7,
followed by a plateau phase between 2003 and 200819.
Two identical follow-up surveys were conducted in 2013 and 2018, while
in the latter study spirometry was also performed in children with a
positive history of wheeze/asthma and in a random sample of negative
controls. Here, we present the results of the last two surveys, aiming
to provide data on the prevalence trends of childhood asthma over a
period of 40 years (1978-2018) in an urban environment in Greece.