Children born to women who are exposed to noise during pregnancy could develop hearing loss and mental retardation, says a study that reviewed existing research linking noise pollution and the health of newborns, infants and teenagers.
The study, which was conducted by doctors from Delhi and Lucknow before being released last month, said newborns exposed to sound above 45 decibels — equivalent to that emitted by light traffic — are at the risk of an increased heart and respiratory rate. Doctors said older children exposed to noise pollution tend to have learning disabilities and attention difficulties, while teenagers, who live in noisy neighbourhoods, are at increased risk of having insulin resistance, hypertension, stress ulcers and cardiovascular diseases, the study said.
Some doctors expressed scepticism about the study, but said current evidence neither proves nor disproves the ill-effects of noise pollution on children.
“Theoretically it is possible, but we don’t know how exposure to high decibel levels can impact a child’s health. It is very similar to the smoking debate, where some smokers live healthy even when non-smokers develop cancer,” said Dr Sameer Sadawarte, pediatrician, Fortis Hospital Mulund. “It is challenging to do a study where you expose women to loud sound and see how it impacts them. It would be unethical to do so.”
Dr Prerna Batra, associate professor of pediatric medicine department at the Delhi-based University of Medical Sciences and the co-author of the study, said: “There are isolated studies, but it is not yet fully understood how
noise pollution triggers medical conditions.”
The study, published in ‘Indian Pediatrics’, found pregnant women living in areas with high sound decibels are worst affected.
“Certain studies which have shown that pregnant women residing near airports have greater acoustic damage of foetus compared to those residing in quieter environment,” said co-author Dr Neha Thakur, Hind Institute of Medical Sciences, Lucknow, Uttar Pradesh.
Thakur added that the hazards of noise pollution are higher in children compared to adults. “In a child, everything is developing so a developing cochlea is more susceptible to acoustic trauma.”
It is the reason why doctors keep noise levels at the minimum in neo-natal intensive care units as babies can have heart conditions if they are exposed to high decibel sounds. “Newborns, especially pre-terms and sick babies in the neonatal ICU, are certainly affected deleteriously with sounds, either high frequency or even low frequency constant sounds,” said Dr Samir Dalwai, president of Indian Academy of Pediatrics.
“This alters their sleep pattern as well as breathing patterns and also circadian rhythms leading to cardiovascular difficulties.”
Batra said although the mechanism of injury is not well established, there is an urgent need to have guidelines to control noise pollution.
“Several studies globally show that noise pollution can impact the unborn, newborn and older children’s healthy growth.”