Women and girls whose grandfathers or great-grandfathers began smoking at an early age tend to have more body fat, research that taps into the extraordinary 30-year Children of the 90s study at the University of Bristol in the United Kingdom has found, writes Steven Morris for The Guardian.
In an earlier piece of work it was discovered that if a father started smoking regularly before reaching puberty, then his sons, but not daughters, had more body fat than expected.
Now researchers believe they have pinpointed higher body fat in females with grandfathers or great-grandfathers who began smoking before the age 13. No effects were observed in male descendants.
The research, just published in the journal Scientific Reports, suggests that exposure to substances can lead to changes that may be passed through the generations – though the team behind the research concedes that much more work is needed to confirm this and understand how it may happen.
They have been able to spot the possible link because of the detail and depth of inter-generational data the University of Bristil study provides, and it is an example of findings that the scientists could not have anticipated when it was launched in 1991, according to The Guardian story published on 21 January 2022.
Professor Jean Golding, the founder of Children of the 90s and lead author of the latest report, praised the participants in the study – an original cohort of 14,000 pregnant women who agreed to take part plus, now, their children and grandchildren.
Other pieces of research over the decades that could not have been foreseen include the finding 20 years ago that women who eat oily fish during pregnancy, even only once every two weeks, have children with sharper eyesight. This was believed to be the first time diet in pregnancy was shown to be associated with a child’s visual development.
A study published in 2013 concluded that iodine deficiency in pregnancy could have an adverse effect on children’s mental development. The discovery was made possible because the study had urine samples from early in participants’ pregnancies and detailed records of what the expectant mothers were eating.
Yet another finding was that early signs of a genetic liability to Type 2 diabetes could be spotted in children as young as eight and a link was also made between peanut allergies and skin cream containing peanut oil. The Children of the 90s project has even allowed experts to examine how wounds heal by looking at participants’ BCG vaccine scars.
The Guardian story continues: For the latest study, researchers dug into data on the smoking experiences of grandfathers and great-grandfathers. They could not look into the smoking of grandmothers and great-grandmothers as so few smoked, but were confident they would have reasonably reliable data from the male side of the family because they were likely to boast about smoking at a very young age.
Link to the full story in The Guardian below.
University of Bristol material
Granddaughters and great-granddaughters of men who start to smoke before puberty, have more body fat than expected, research shows
This is a University of Bristol release published on 21 January 2022.
A new study, led by the University of Bristol and published in Scientific Reports, has reported increased body fat in females whose grandfathers or great-grandfathers began smoking before puberty.
Experiments with model studies elsewhere have shown that exposure of males to certain chemicals before breeding can have effects on their offspring. There has, however, been doubt as to whether this phenomena is present in humans and whether any apparent effects may be more readily explained by other factors.
To investigate effects of prepubertal exposures in humans, scientists from the University of Bristol have studied possible effects of ancestral prepubertal cigarette smoking on participants in the Children of the 90s, a study of more than 14,000 individuals.
In earlier research from 2014 they found that if a father started smoking regularly before reaching puberty (before 11 years of age), then his sons, but not his daughters, had more body fat than expected.
In the newly published study, they extended this analysis to earlier generations using recently collected data on the grandfathers and great-grandfathers of study participants obtained by questionnaires.
They discovered higher body fat in females whose paternal grandfathers or great-grandfathers had started smoking before age 13 compared to those whose ancestors started smoking later in childhood (age 13 to 16). No effects were observed in male descendants.
Further research will be needed to confirm these observations in other longitudinal studies and to expand the investigation into other transgenerational effects and ancestral exposures.
Professor Jean Golding, lead author of the report, said: “This research provides us with two important results.
“First, that before puberty, exposure of a boy to particular substances might have an effect on generations that follow him. 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.
“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.”
Study details
Human transgenerational observations of regular smoking before puberty on fat mass in grandchildren and great-grandchildren
Jean Golding, Steve Gregory, Kate Northstone, Marcus Pembrey, Sarah Watkins, Yasmin Illes-Caben and Matthew Suderman
Published in Scientific Reports on 21 January 2022. Volume 12, article: 1139 (2022)
Abstract
Previously, using data from the Avon Longitudinal Study of Parents and Children (ALSPAC) we showed that sons of fathers who had started smoking regularly before puberty (< 13 years) had increased fat mass during childhood, adolescence, and early adulthood.
We now show that if the paternal grandfather had started smoking pre-puberty, compared with later in childhood (13–16 years), his granddaughters, but not grandsons, had evidence of excess fat mass at two ages: mean difference + 3.54 kg; (P with 1-tailed test) = 0.043 at 17 years, and + 5.49 kg; (P1 = 0.016) at age 24.
When fathers of maternal grandfathers had started smoking pre-puberty, their great-granddaughters, but not great-grandsons, had excess body fat: + 5.35 kg (P1 = 0.050) at 17, and + 6.10 kg (P1 = 0.053) at 24 years. Similar associations were not found with lean mass, in a sensitivity analysis.
To determine whether these results were due to the later generations starting to smoke pre-puberty, further analyses omitted those in subsequent generations who had smoked regularly from < 13 years. The results were similar.
If these associations are confirmed in another dataset or using biomarkers, this will be one of the first human demonstrations of transgenerational effects of an environmental exposure across four generations.
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