Abstract:
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Introduction: Three recent systematic reviews suggested a
relationship between noise exposure and adverse birth outcomes.
The aim of this review was to evaluate the evidence for the
World Health Organization (WHO) noise guidelines and conduct an
updated systematic review of environmental noise, specifically
aircraft and road traffic noise and birth outcomes, such as
preterm birth, low birth weight, being small for gestational age
and congenital malformations. Materials and methods: We reviewed
again all the papers on environmental noise and birth outcomes
included in the previous three systematic reviews and conducted
a systematic search on noise and birth outcomes to update
previous reviews. Web of Science, PubMed and Embase electronic
databases were searched for papers published between June 2014
(end date of previous systematic review) and December 2016 using
a list of specific search terms. Studies were also screened in
the reference list of relevant reviews/articles. Further
inclusion and exclusion criteria for the studies provided by the
WHO expert group were applied. Risk of bias was assessed
according to criteria from the Newcastle-Ottawa quality
assessment scale for case-control and cohort studies. Finally,
we applied the GRADE principles to our systematic review in a
reproducible and appropriate way for judgment about quality of
evidence. Results: In total, 14 studies are included in this
review, six studies on aircraft noise and birth outcomes, five
studies (two with more or less the same population) on road
traffic noise and birth outcomes and three related studies on
total ambient noise that is likely to be mostly traffic noise
that met the criteria. The number of studies on environmental
noise and birth outcomes is small and the quality of evidence
generally ranges from very low to low, particularly in case of
the older studies. The quality is better for the more recent
traffic noise and birth outcomes studies. As there were too few
studies, we did not conduct meta-analyses. Discussion: This
systematic review is supported by previous systematic reviews
and meta-analyses that suggested that there may be some
suggestive evidence for an association between environmental
noise exposure and birth outcomes, although they pointed more
generally to a stronger role of occupational noise exposure,
which tends to be higher and last longer. Very strict criteria
for inclusion and exclusion of studies, performance of quality
assessment for risk of bias, and finally applying GRADE
principles for judgment of quality of evidence are the strengths
of this review. CONCLUSIONS: We found evidence of very low
quality for associations between aircraft noise and preterm
birth, low birth weight and congenital anomalies, and low
quality evidence for an association between road traffic noise
and low birth weight, preterm birth and small for gestational
age. Further high quality studies are required to establish such
associations. Future studies are recommended to apply robust
exposure assessment methods (e.g., modeled or measured noise
levels at bedroom facade), disentangle associations for
different sources of noise as well as daytime and nighttime
noise, evaluate the impacts of noise evens (that stand out of
the noise background), and control the analyses for confounding
factors, such as socioeconomic status, lifestyle factors and
other environmental factors, especially air pollution. |