Respiratory tract infections in young children are associated with an
increased risk of asthma and worsening lung function later in life, according
to new European research.
In an international study of one hundred and fifty-four thousand, four hundred
and ninety-two children, it was found that those who had had upper respiratory
tract infections, such as colds, sinusitis, laryngitis, tonsillitis,
pharyngitis, and otitis media, by the age of five years, had a 1.5-fold
increase in the risk of developing asthma later in life. Children who had lower
respiratory tract infections such as bronchitis, bronchiolitis , pneumonia, and
common chest infections were twice as likely to develop asthma and were also
more likely to have worse lung function.
The researchers from the Netherlands noted that their results support the
hypothesis that early respiratory tract infections may influence the
development of respiratory diseases and, in particular, early lower respiratory
tract infections seem to have the greatest negative impact on function. lungs
and the risk of developing asthma. However, at this stage it is impossible to
say for sure whether the relationship is causal. Further studies that measure
lung function and breathing parameters from birth are needed to investigate
whether infections are the cause of asthma and lower lung function. Research
aimed at preventing or treating respiratory tract infections at an early stage,
possibly through vaccination, will also shed light on this issue. Lung function
and asthma are only partially related, the authors say. Lung function may be
affected without affecting symptoms, or it may lead to asthma or other
complaints such as wheezing. In addition, the child may be diagnosed with
asthma, and lung function may change slightly, for example, because the patient
is taking asthma medication, the authors note. The researchers analyzed data
from thirty-seven groups of children from several European countries born
between 1989 and 2013. Children were included in this meta-analysis if data
were available for early respiratory tract infections (6 months to 5 years) and
for asthma or impaired lung function. The length of follow-up varied between
groups, but ranged from birth to 4-15 years of age. The children’s lung
function was measured as they got older using a spirometer. Parameters such as
a measure of the amount of air that a person can exhale after the maximum
possible inspiration (FVC), the volume of exhalation in one second (FEV1), the
speed of exhaled air after exhaling three-quarters of the total lung volume
during forced exhalation (FEF75) were noted. children, lung function was not
measured, the youngest children whose breathing parameters were assessed were
at the age of four years, and the oldest at fifteen. The median age was eight
years. The researchers adjusted parameters for factors that may affect the
results, such as socioeconomic status, lifestyle, birth weight, gestational age
at birth, gender, age, height, and ethnicity. They found that upper respiratory
tract infections were not associated with worse lung function later in life.
However, lower respiratory tract infections at nearly all ages have been
associated with worse lung function, as shown by lower FVC, FEV1, and FEF75.
The authors believe that it will be interesting to study the long-term effects
in adulthood of respiratory tract infections on lung function and asthma. Lung
function in childhood is most likely related to lung function in adulthood.
Going forward, the scientists want to study the roles of antibiotics,
paracetamol and smoke exposure in the relationship between respiratory tract
infections and lung function or asthma. They also plan to clarify what
percentage of the association between respiratory tract infections and asthma
can be explained by changes in lung function, and whether the association
changes when early wheezing is taken into account.