Children more likely to be overweight if mothers smoke, study finds

The children of Irish mothers who smoke are more likely to be overweight or obese, according to a new study.

The University College Cork research on primary carers, 98% of whom were biological mothers, discovered a link between maternal smoking postnatally and obesity in children aged three and five.

It found that children exposed to maternal smoking or primary carers’ smoking are 30% more likely to be overweight or obese at age three, and 31% more likely to be obese or overweight at age five, compared with children of non-smoking mothers.

The study’s lead author, Salome Sunday, said there is a theory that secondhand smoke is linked to a child’s weight.

“It has been hypothesised that inhaling the chemicals in tobacco smoke (secondhand smoke exposure) may cause impaired metabolic and immune functions, leading to an increase in the child’s susceptibility to obesity,” she said.

It is understood the research — which used findings gathered from more than 11,100 children in the Growing Up in Ireland study — is one of the first Irish studies to examine how secondhand smoke from primary carers is linked to childhood obesity.

“Both childhood obesity and secondhand childhood exposure are public health issues in Ireland,” said the authors.

Childhood obesity is linked to a string of health conditions later in life, including an increased risk of type 2 diabetes, heart diseases, cancer, as well as lifelong overweight and obesity.

Public health professional Ms Sunday, from the School of Public Health in UCC, said she believes voluntary smoke-free households need to be vigorously promoted.

The findings also suggested that the risk of childhood overweight or obesity following childhood secondhand smoke exposure was independent of both low birth weight and breastfeeding.

The study authors revealed that current estimates show that, in this country, about 7% of girls and 6% of boys aged from four to 16 years are obese, putting Ireland at 58 out of 200 countries in the childhood obesity charts.

The study, Impact of Carers’ Smoking Status on Childhood Obesity in the Growing Up in Ireland Cohort Study, was carried out by Ms Sunday and Zubair Kabir in the School of Public Health, UCC.

The research, which has just been published in the International Journal of Environmental Research and Public Health, found that for six out of 10 participating children neither caregiver/parent smoked.

The research also found that primary carers —mainly made up of biological mothers — who reported smoking proportionately breastfeed their babies less.

The study found that, overall, carers who smoked were more likely to have a household income in the lowest group, to be unemployed, and to consume alcohol weekly.