Lung function measurements in children - copsac
Lung function measurements in children - copsac
Lung function measurements in children - copsac
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epigenetic factors. Acute environmental factors are directly associated with epigeneticdependent<br />
disease phenotypes (165-167). Speculations may consider differ<strong>in</strong>g co<strong>in</strong>fections<br />
with an agent of less virulence <strong>in</strong>clud<strong>in</strong>g bacterial colonization (126, 168) or<br />
other viral <strong>in</strong>fections. There is <strong>in</strong>creas<strong>in</strong>g evidence that rh<strong>in</strong>oviruses (RV) are able to<br />
cause lower airway <strong>in</strong>fections and to <strong>in</strong>duce wheez<strong>in</strong>g <strong>in</strong> young <strong>children</strong>, and it may be<br />
as common as RSV as a cause of bronchiolitis (142, 169-171). Human<br />
metapneumovirus (hMPV) has also recently been recognised as one of several other<br />
viral pathogens that can cause acute bronchiolitis <strong>in</strong> <strong>in</strong>fants (172, 173), the rema<strong>in</strong><strong>in</strong>g<br />
be<strong>in</strong>g ma<strong>in</strong>ly para<strong>in</strong>fluenzavirus and adenovirus. However, the long-term effect of this<br />
and other viral agents on lung <strong>function</strong> and symptoms later <strong>in</strong> childhood is not yet fully<br />
<strong>in</strong>vestigated.<br />
Neonatal lung <strong>function</strong><br />
Pr<strong>in</strong>cipal f<strong>in</strong>d<strong>in</strong>gs<br />
We found no association between basel<strong>in</strong>e lung <strong>function</strong> and bronchial responsiveness<br />
<strong>in</strong> neonates and later development of bronchiolitis with RSV <strong>in</strong>fection compared to the<br />
control group.<br />
Limitations and Strengths<br />
We used strict def<strong>in</strong>ition of bronchiolitis <strong>in</strong> accordance with a recent review (127). Our<br />
def<strong>in</strong>ition of bronchiolitis is consistent with the Anglo-Saxon def<strong>in</strong>ition <strong>in</strong>clud<strong>in</strong>g<br />
widespread f<strong>in</strong>e crepitations and sometimes expiratory rhonchi on auscultation <strong>in</strong> the<br />
def<strong>in</strong>ition (127, 174-176). In the American literature, the def<strong>in</strong>ition sometimes <strong>in</strong>cludes<br />
all first-time wheez<strong>in</strong>g <strong>in</strong>fants with associated respiratory-tract <strong>in</strong>fection (144, 177,<br />
178). We recognize the lack of evidence for the effect of steroids for bronchiolitis (179-<br />
184) but took the pragmatic approach to <strong>in</strong>clude their use <strong>in</strong> our def<strong>in</strong>ition of the more<br />
acute cases realiz<strong>in</strong>g this is a well established cl<strong>in</strong>ical practice and <strong>in</strong>dicat<strong>in</strong>g a certa<strong>in</strong><br />
cl<strong>in</strong>ical severity. Also, we recognize that the diagnosis of acute bronchiolitis is likely to<br />
comprise <strong>in</strong>fants with first acute attack of asthma, but this would have biased the risk<br />
estimates aga<strong>in</strong>st the null hypothesis assum<strong>in</strong>g such <strong>in</strong>fants with underly<strong>in</strong>g asthma<br />
would have had reduced lung <strong>function</strong> and bronchial hyperresponsiveness.<br />
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