NEW DELHI: Greater exposure to air pollution particulate matter (PM2.5, PM10) and Nitrogen dioxide (NO2) in the three months before conception can raise the risk of childhood obesity to two years after birth, according to a study on Thursday.
Past research has linked air pollution exposure during pregnancy to a broad range of health problems in children, including respiratory issues and a higher risk for chronic diseases such as obesity and heart problems.
But, the new study by an international team of researchers from the US and China focused on the preconception period -- typically defined as the three months before a pregnancy begins.
Environmental exposures during this timeframe can affect the health of sperm and eggs, which are in their final stages of growth, said the team, in the paper published in the journal Environmental Research.
The study included 5, 834 mother-child pairs recruited from maternity clinics in Shanghai.
The findings revealed that increased exposure to PM2.5, PM10, and NO2 before pregnancy can spike BMI or BMIZ -- a standardised score that shows how a child’s BMI compares to others of the same age and sex.
“These findings imply that the three months before conception are important, and that people who plan to bear children should consider taking measures to lower their air pollution exposure to reduce their children’s risk for obesity, ” said Jiawen Liao, postdoctoral research associate at the Keck School of Medicine, University of South California (USC).
The researchers found that a higher level of exposure to PM2.5 during the preconception period was associated with a 0.078 increase in child BMIZ at age two, while a higher level of exposure to PM10 was associated with a 0.093 kg/m2 increase in BMI at age two.
From six months onward, children with higher preconception exposure to all three pollutants had higher weight, BMI, and BMIZ growth rates.
While “the magnitude is small, but because air pollution is widespread and everybody is exposed, the risk of air pollution exposure on children’s obesity risk may be substantial and may start before their mothers’ pregnancy, ” said Zhanghua Chen, assistant professor at the Keck School.
The study is observational, and more research is needed to determine the risk. Yet the findings suggest that people can take action now to minimise potential harm to themselves and their children, the researchers said.