How Grandparents’ Smoking Affects Grandchildren’s Health

One of the most important discoveries in modern medicine is that environmental exposures can leave epigenetic marks on DNA — changes that do not alter the genetic code itself but affect how genes are expressed. These marks can be passed from one generation to the next [citation:8].

• 🧬 DNA methylation changes: Smoking induces specific methylation patterns in the genome, particularly at sites like the AHRR gene (cg05575921), which has been identified as the most reliable molecular signature of tobacco smoke exposure [citation:8].
• 🔄 Transgenerational transmission: These epigenetic marks can be passed through germ cells (sperm and eggs), affecting grandchildren who were never directly exposed to smoke [citation:4][citation:8].
• 👵 Grandmaternal effects: A 2025 NIH review confirmed that “grandmaternal smoking increases the risk of asthma and reduced lung function in grandchildren” [citation:4].

A large 2024 population-based register study from Sweden examined sex disparities in asthma related to parental and grandmaternal smoking habits [citation:7].

• 📊 Key finding: The risk of grandchild asthma was transmitted specifically through the maternal line — grandmothers who smoked while pregnant with the child’s mother increased the grandchild’s asthma risk [citation:7].
• 👦 Paternal effects on grandsons: The study also found that paternal smoking at conscription (military enlistment) was related to an increased risk of asthma in grandsons [citation:7].
• 🔬 Mechanism: This suggests that smoke-induced epigenetic changes can be carried through eggs (maternal line) and sperm (paternal line) across generations [citation:4][citation:7].

Research from the Woolcock Institute of Medical Research in Australia has made significant contributions to understanding transgenerational smoking effects [citation:1].

• 📈 Key statement: “Epidemiological studies indicate a link between smoking and asthma risk that can be passed down through generations. If your grandmother smoked, it could actually increase the likelihood of asthma in subsequent generations” [citation:1].
• 🔬 Professor Brian Oliver’s warning: “The largest modifiable thing that you can do to reduce the incidence of asthma in children is to stop smoking. This applies equally to women who smoke or who are living in smoking households during pregnancy” [citation:1].
• 🩺 Clinical implications: Grandmothers who smoked during pregnancy may have unknowingly set in motion epigenetic changes that affect their grandchildren’s respiratory health [citation:1][citation:4].

While much attention has focused on maternal smoking, emerging evidence shows that paternal smoking also has transgenerational effects [citation:4][citation:7].

• 🧬 Sperm epigenetic markers: “Paternal smoking, even before conception, has been linked to changes in sperm epigenetic markers, which may be transmitted to the offspring and disrupt developmental processes” [citation:4].
• 👦 Sex-specific effects: The Swedish study found that paternal smoking effects were more pronounced in male grandchildren — grandsons were at higher risk than granddaughters [citation:7].
• 🔬 Rodent evidence: Animal studies have demonstrated that “paternal stressors can epigenetically modify sperm, especially impacting imprinted genes vital for placental development and fetal growth” [citation:8].

Beyond epigenetic inheritance, there is a more immediate way grandparents’ smoking affects grandchildren: thirdhand smoke (THS). This is the toxic residue that remains on surfaces after a cigarette is extinguished [citation:5][citation:9].

• 🧪 Toxic chemicals: Thirdhand smoke contains over 26 cancer-causing chemicals, including hydrogen cyanide (used in chemical weapons), butane (lighter fluid), arsenic, lead, carbon monoxide, and polonium-210 (a highly radioactive carcinogen) [citation:5].
• 🕰️ Long-lasting persistence: Thirdhand smoke “can linger in homes, cars, and even hospital environments for years after smoking ceases” [citation:9].
• 👶 Children at greatest risk: Infants and toddlers are particularly vulnerable because they crawl on floors, touch surfaces, and put their hands in their mouths [citation:1][citation:3].
• 🩺 Health impacts: Thirdhand smoke exposure has been linked to asthma, respiratory infections, cancer risk, and cellular DNA damage [citation:5][citation:9].

Many grandparents believe that smoking outside protects their grandchildren. This is false. The toxic residue clings to hair, skin, and clothing — and is transferred directly to grandchildren during hugs and cuddles [citation:3].

• 👕 Transfer through touch: “When you smoke outside and then hold your baby, the smoke and toxic chemicals can get on the baby. Wear clean clothes when you hold your baby” [citation:3].
• 🔬 Molecular changes: A recent proteomics study on dermal (skin) exposure to thirdhand smoke in humans revealed alterations in numerous cellular pathways indicative of the potential to cause atherosclerosis, inflammatory response, and dermatitis [citation:9].
• 📊 Cancer risk: A cancer risk assessment found that early-life exposure (ages 1 to 6) to tobacco-specific nitrosamines in thirdhand smoke exceeded the upper-bound risk recommended by the US Environmental Protection Agency in 77% of smokers’ homes and 64% of non-smokers’ homes [citation:9].
• 🩺 Clinical outcomes: A study of children whose parents smoke found that those with higher levels of thirdhand smoke exposure were at increased risk of viral infections, respiratory conditions, and bacterial infections [citation:9].

All tobacco smoke is harmful to grandchildren — regardless of brand or source. Native cigarettes (Playfare, Canadian, DuMont, Nexus, Rolled Gold) cause the same epigenetic changes, DNA methylation, and thirdhand smoke residue as commercial brands [citation:4][citation:8].

• 💰 Cost savings: Native cigarettes cost $29-50 per carton — compared to $140-180 for commercial brands — a savings of 70-80%.
• 🚫 Not “safer” for grandchildren: Native cigarettes produce the same carcinogens and epigenetic toxins as any other cigarette.
• 📦 Online delivery: Cigstore.ca ships to every province and territory with $29 flat shipping (free over $290).
• 👶 Medical note: If you are a grandparent who wants to protect your grandchildren, no form of smoking is safe. Quitting is the only protective option.