New research has turned up another reason for women to avoid smoking during pregnancy. A recent study in the journal Gut Microbes has found an association between mothers smoking during pregnancy and a higher risk of their children becoming overweight or obese.
Childhood obesity is a growing concern globally, affecting more than 18 per cent of children and adolescents aged five to 19 in 2020, a startling increase from just four per cent back in 1975.
And it's a big problem. The study notes childhood obesity is linked to such negative outcomes as poorer health and lower self-esteem, and an increased likelihood of being bullied.
Anita Kozyrskyj, a microbiome epidemiologist and professor of pediatrics at the University of Alberta, is the co-senior author of the study. Kozyrskyj, who is a member of the Women and Children's Health Research Institute, has done a lot of research on early life factors that affect infant gut bacteria. These factors include how infants are born, how they're fed, the health of the mother and stress during her pregnancy.
Kozyrskyj says other researchers have shown that women who smoke during pregnancy tend to have babies who become overweight in childhood. But she says her group's study represents new ground because they show an association that might indicate the reason. And it's in those microbes found in the gut.
"We've known that for a long time. We just didn't know how it happened," Kozyrskyj says. "There may be many ways, but in our study, we showed one way is by changing the gut bacteria in the infant."
Kozyrskyj and the team used data from more than 1,500 children from the Canadian Healthy Infants Longitudinal Development (CHILD) Cohort. The team collected data from families that told about the mothers' environmental and lifestyle factors during pregnancy and those of their children from birth to age three. Weight outcomes were measured at one and three years of age. Stool samples were collected at three and 12 months of age and analyzed to get a profile of the bacteria in them.
The researchers found that the increased risk of children being overweight and obese was associated with the amount and diversity of a phylum of bacteria known as Firmicutes. It was discovered that maternal smoking during pregnancy significantly increased the abundance of Firmicutes bacteria in the gut.
