A brand new study suggests boys who smoke of their early teens risk damaging the genes of their future children, increasing their possibilities of developing asthma, obesity and low lung function.

Research published today [31^st August 2023] in Clinical Epigenetics is the primary human study to disclose the biological mechanism behind the impact of fathers’ early teenage smoking on their children.

Researchers from the University of Southampton and the University of Bergen in Norway investigated the epigenetic profiles of 875 people, aged 7 to 50, and the smoking behaviours of their fathers.

They found epigenetic changes at 19 sites mapped to 14 genes in the youngsters of fathers who smoked before the age of 15. These changes in the way in which DNA is packaged in cells (methylation) regulate gene expression (switching them on and off) and are related to asthma, obesity and wheezing.

Our studies in the big international RHINESSA, RHINE and ECRHS studies have shown that the health of future generations is dependent upon the actions and decisions made by young people today – long before they’re parents – particularly for boys in early puberty and moms/grandmothers each pre-pregnancy and while pregnant. It is absolutely exciting that we’ve got now been capable of discover a mechanism that explains our observations within the cohorts.”

Professor Cecilie Svanes from the University of Bergen and Research Director of the RHINESSA study

“Changes in epigenetic markers were way more pronounced in children whose fathers began smoking during puberty than those whose fathers had began smoking at any time before conception,” says co-lead creator of the paper Dr Negusse Kitaba, Research Fellow on the University of Southampton. “Early puberty may represent a critical window of physiological changes in boys. That is when the stem cells are being established which can make sperm for the remainder of their lives.”

The team also compared the paternal preconception smoking profiles with individuals who smoked themselves and people whose moms smoked before conception.

“Interestingly, we found that 16 of the 19 markers related to fathers’ teenage smoking had not previously been linked to maternal or personal smoking,” says Dr Gerd Toril Mørkve Knudsen from the University of Bergen and co-lead creator of the study. “This implies these recent methylation biomarkers could also be unique to children whose fathers have been exposed to smoking in early puberty.”

The variety of young people smoking has fallen within the UK in recent times. But co-author Professor John Holloway, from the University of Southampton and the NIHR Southampton Biomedical Research Centre, is worried about children taking on vaping.

“Some animal studies suggest that nicotine would be the substance in cigarette smoke that’s driving epigenetic changes in offspring,” says Professor Holloway. “So it’s deeply worrying that teenagers today, especially teenage boys, at the moment are being exposed to very high levels of nicotine through vaping.

“The evidence from this study comes from people whose fathers smoked as teenagers within the 60s and 70s, when smoking tobacco was way more common. We won’t definitely make sure vaping could have similar effects across generations, but we shouldn’t wait a few generations to prove what impact teenage vaping may need. We want to act now.”

The brand new findings have significant implications for public health. They suggest a failure to deal with harmful exposures in young teenagers today could damage the respiratory health of future generations, further entrenching health inequalities for a long time to come back.

The University of Southampton’s LifeLab programme engages with young people to indicate how lifestyle selections can impact their health and the health of any children they might have in the long run. Dr Kath Woods-Townsend, LifeLab Programme manager says: “Parents, teachers and young people themselves are concerned concerning the impact of vaping. We’re working with our Youth Panel to know the role vaping plays of their lives and to cocreate resources that can help inform young people concerning the risks.”

Fathers’ preconception smoking and offspring DNA methylation is published in Clinical Epigenetics and is on the market to read online.