Research on a cohort of Chinese mothers and their children has found exposure to elevated levels of particulate matter in the three months prior to conception is linked with higher childhood obesity risk up to two years after birth.
The additional presence of high levels of NO2 was also found to be associated with higher body weight growth.
Researchers from the University of Southern California’s Keck School of Medicine, Duke University and Fudan University in Shanghai, China studied a cohort of 5,834 mothers/children from three months prior to conception to the child reaching two years old.
Exposures to PM2.5, PM10, and NO2 before conception and each trimester of pregnancy were estimated using high-resolution models matched at residential addresses. The Children’s weight and BMI were assessed every three months.
Those members of the cohort with a low level of exposure to pollutants were compared to those with a relatively high exposure levels.
It was found that greater exposure to PM2.5, PM10 and NO2 before pregnancy was linked to increases in BMI or BMIZ (a measurement that compares a child’s BMI to the average BMI for their age and gender)
Higher weight, BMI, and BMIZ growth rates between six months and two years of age months of life were also associated with higher NO2 and PM exposure prior to conception.
Weight growth was also found to be more prevalent in males and the children of mothers under 35 years old.
Jiawen Liao, PhD, a postdoctoral research associate in population and public health sciences at the Keck School of Medicine and first author of the study said: ‘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.’
Zhanghua Chen, PhD, an assistant professor of population and public health sciences at the Keck School of Medicine and the study’s senior author added: ‘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.’