Abstract:
Poor ventilation at day care centres (DCCs) was
already reported, although its effects on attending children are
not clear. This study aimed to evaluate the association between
wheezing in children and indoor CO2 (a ventilation surrogate
marker) in DCC and to identify behaviours and building
characteristics potentially related to CO2. In phase I, 45 DCCs
from Lisbon and Oporto (Portugal) were selected through a
proportional stratified random sampling. In phase II, 3 months
later, 19 DCCs were further reassessed after cluster analysis
for the greatest difference comparison. In both phases, children’s
respiratory health was assessed by ISAAC-derived
questionnaires. Indoor CO2 concentrations and building characteristics of the DCC were evaluated in both phases,
using complementary methods. Mixed effect models were
used to analyze the data. In phase I, which included 3,186
children (mean age 3.1±1.5 years), indoor CO2 concentration
in the DCC rooms was associated with reported wheezing in
the past 12months (27.5 %) (adjusted odds ratio (OR) for each
increase of 200 ppm 1.04, 95 % CI 1:01 to 1:07). In phase II,
the association in the subsample of 1,196 children seen in 19
out of the initial 45 DCCs was not significant (adjusted OR
1.02, 95 % CI 0.96 to 1.08). Indoor CO2 concentration was
inversely associated with the practices of opening windows
and internal doors and with higher wind velocity. A positive
trend was observed between CO2 and prevalence of reported
asthma (4.7 %). Conclusion: Improved ventilation is needed
to achieve a healthier indoor environment in DCC.