MONTREAL—Children of mothers who are obese at the time of pregnancy or smoke have a significantly higher risk of developing obesity by the time they are 3 years old, according to a new study published in the Archives of Pediatric and Adolescent Medicine.
Researchers from the University of Montreal analyzed data drawn from the Quebec Longitudinal Study of Child Development that ran from 1998 to 2006. They focused on 1,957 children whose height and weight measurements had been taken yearly, from age 5 months to 8 years old, and recorded in a database. The researchers identified three trajectory groups—children with low but stable BMI; children with moderate BMI; and children whose BMI was elevated and rising, called high-rising BMI.
They discovered the trajectories of all three groups were similar until the children were about 2.5 years old, at which time the BMIs of the high-rising group of children began to increase dramatically. By the time the children moved into middle childhood, more than 50% of them were obese.
Researchers found two factors contributed to obesity—the mothers’ weight around the time they gave birth and whether the mothers smoked. A child with a mother who was overweight or who smoked during pregnancy was significantly more likely to be in the high-rising group. The two factors were found to be much more important than the other criteria that were studied, such as the child's birth weight.