Children of the '90s: Grandfathers smoking habits might affect girls' weight

Prof Jean Golding (left) said children's weight "may be not so much to do with their current diet and exercise, rather than the lifestyle of their ancestors"

Whether your grandfather smoked could be responsible for how much body fat you have, a study has found.

The Children of the 90s research suggests that granddaughters of men who smoked before the age of 13, carry more body fat.

More than 14,000 people were included in the findings from the University of Bristol.

The study's lead author, professor Jean Golding, said no effects were observed in male descendants.

The Children of the 90s is a long-term health research project.

It enrolled more than 14,000 pregnant women in 1991 and 1992 and followed the health and development of the parents and their children through the generations.

The findings showed higher body fat in females whose paternal grandfathers or great-grandfathers had started smoking before the age of 13

Previous research in 2014 found that if a father started smoking regularly before reaching puberty at 11 years old, then his sons, but not his daughters, carried more body fat than expected.

However, in the newly published study, the analysis was extended to earlier generations using recently collected data on the grandfathers and great-grandfathers of study participants.

'Lifestyle of ancestors'

"First, that before puberty, exposure of a boy to particular substances might have an effect on generations that follow him," Prof Golding said.

"Second, one of the reasons why children become overweight may be not so much to do with their current diet and exercise, rather than the lifestyle of their ancestors or the persistence of associated factors over the years."

The findings showed higher body fat in females whose paternal grandfathers or great-grandfathers had started smoking before the age of 13 compared to those whose ancestors began smoking after that age.

"If these associations are confirmed in other datasets, this will be one of the first human studies with data suitable to start to look at these associations and to begin to unpick the origin of potentially important cross-generation relationships," she said.

The study's authors have said further research would be needed to confirm these observations.