THURSDAY, Dec. 12, 2024 (HealthDay News) -- Sneaking cigarettes might seem like a harmless pre-teen rite of passage, but it’s more dangerous than you think, a new study warns. 

Regular smoking at a young age doesn’t just lead to a higher chance of smoking later in life -- it can also cause serious harm to young hearts.

Experts have understood that children who smoked earlier in life were more likely to continue the habit, and the risks that come with it, later into their lives. Now, the new study gives a better idea of the damage it does early on.

“Teen smoking doesn’t just increase the risk of heart disease later in life -- it causes early and lasting damage to heart muscle and function,” said Dr. Emily Bucholz, an assistant professor of pediatrics at the University of Colorado School of Medicine.

Until now, there wasn't a lot of data on cardiac structure and function in healthy children, since assessing the hearts of healthy young people is uncommon. 

Overall, persistent smoking from childhood to young adulthood was associated with an over 50% increased risk of premature heart damage, the study, published Dec. 11 in the Journal of the American College of Cardiology (JACC), showed. The damage, such as an enlarged heart or increased pressure in blood flow to the heart, was evident by the age of 24.

This analysis followed more than 1,900 young adults who filled out smoking questionnaires at ages 10, 13, 15, 17 and 24, and underwent tests to measure heart structure and function at ages 17 and 24.

At baseline, 0.3% of children smoked cigarettes at age 10, which increased to 26% in young adults by their mid-20s. Results suggest that left ventricular hypertrophy (thickening of the heart wall) prevalence increased from almost 3% to nearly 5% at age 24. 

Smoking during this time of growth was associated with 33% to 52% odds of premature structural and functional cardiac injury. 

“The increase of cardiac mass structure in just a few years of smoking should convey how dangerous the consequences are for people who continue to smoke from a young age,” said lead author Andrew Agbaje, associate professor of clinical epidemiology and child health at the University of Eastern Finland.

Research suggests that early smoking causes the same type of heart damage that's linked to ischemia (reduced blood flow), inflammation, trauma or chronic diseases.

This study is the largest and longest to track active smoking and repeated heart scans. However, it had some limitations: most participants were white, so the findings might not apply to other racial groups. It also didn’t take into account social factors like the smoking habits of parents or friends.

Regardless, the results should be a "wake-up call for prevention efforts to protect young hearts early,” Bucholz said in a journal news release.

More Information

Learn more about tobacco use among children and teens from the American Lung Association.

SOURCE: American College of Cardiology, press release, Dec. 11, 2024