Fathers' childhood exposure to secondhand smoke may impair their children's lifelong lung health. Digest
Many lung diseases develop slowly over decades, often starting with small lung deficits early in life. But could harmful exposures in one generation quietly shape the health of the next one? A new study from Australia explored whether fathers' exposure to secondhand smoke before puberty was associated with their children's lung function throughout life.
Researchers followed 890 father-child pairs from the Tasmanian Longitudinal Health Study. The fathers reported whether a parent smoked when they were younger than 15. Their children had lung function measured six times between ages 7 and 53, allowing researchers to identify patterns in how their lungs developed and declined over time.
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Here is what the researchers found:
- Children of fathers exposed to secondhand smoke before puberty were more likely to follow a low lung function path over time, particularly in forced expiratory volume (FEV1), a key measure of how much air a person can exhale in one second.
- This FEV1 pattern was even more likely when the children themselves were exposed to secondhand smoke at home during childhood.
- They also showed higher odds of having a faster-than-normal decline in the FEV1 to total exhaled volume (forced vital capacity, or FVC) ratio, which can signal narrowing of the airways as seen in chronic obstructive pulmonary disease (COPD).
- The team tested whether the link could be explained by factors like the fathers' smoking habits, or if the children had asthma, respiratory infections, or were smokers themselves. These factors only explained a small part of the connection.
Mechanistically, these findings suggest that smoke exposure during a boy's preteen years may influence the development of the cells that later produce sperm, affecting how the lungs develop in his future children. These heritable changes, known as epigenetic modifications, do not alter the DNA code itself but can affect how genes are switched on or off during development.
While the study relied on self-reported exposure and lacked genetic data, its findings highlight the importance of protecting children from secondhand smoke. This supports not only their own health but also possibly the health of their future children. In this clip, Dr. Elissa Epel describes how pre-pregnancy parental health impacts offspring.