Secondhand Smoke Heart Risks Many People Still Don’t Know

People are generally familiar with the connection between cigarettes and lung cancer, but a new international study shows that many smokers know much less about the damage tobacco can cause to the heart and brain.

The research, published in BMJ Open, examined findings from two large tobacco surveys covering 46 countries. Researchers found that awareness of cardiovascular risks was consistently lower than awareness of lung cancer risks.

Smokers Know About Cancer, But Not All the Risks

The strongest level of awareness involved lung cancer. About 92% of smokers surveyed understood that cigarettes can cause the disease.

The numbers dropped when researchers asked about cardiovascular problems. Depending on the survey, 80% to 85% of respondents recognized that smoking can contribute to heart disease or heart attacks.

Awareness was lower again for stroke. Only around 66% to 75% of participants identified smoking as a risk factor.

Researchers said the results point to a major gap in public understanding of tobacco’s effects.

How Tobacco Affects the Cardiovascular System

Smoking can affect the cardiovascular system in several ways.

Chemicals in cigarette smoke can damage blood vessel walls and promote inflammation. Over time, these effects can contribute to plaque buildup and narrowed arteries.

Smoking can also increase the likelihood of blood clotting. If a clot blocks blood flow to the heart, it can cause a heart attack. If blood flow to the brain is interrupted, it can result in an ischemic stroke.

Nicotine can additionally increase heart rate and blood pressure, while carbon monoxide interferes with the blood’s ability to carry oxygen.

The Secondhand Smoke Gap Is Even Bigger

The researchers found particularly low awareness of the risks faced by people who do not smoke.

About 77% to 82% of respondents knew that secondhand smoke can cause lung cancer. But only 62% to 73% recognized that exposure can also contribute to heart disease or heart attacks.

In some high-income countries, fewer than half of those surveyed understood the cardiovascular risks associated with secondhand smoke.

The CDC states that even brief exposure can harm the heart and blood vessels. Among adults who do not smoke, secondhand smoke exposure is associated with a 25% to 30% higher risk of coronary heart disease and a 20% to 30% higher risk of stroke.

Why Awareness Makes a Difference

The researchers noted that knowledge about tobacco’s health effects has not improved dramatically over time.

Across the five health effects examined, the average improvement in awareness was only 0.14 percentage point per year.

That matters because people who underestimate the cardiovascular consequences of smoking may not fully understand the benefits of stopping or the importance of protecting others from exposure.

Cutting Back Is Not the Same as Quitting

Reducing cigarette consumption may seem like a way to lower health risks, but smoking even a small number of cigarettes can still carry substantial cardiovascular risks.

Complete cessation provides greater health benefits. After quitting, the body begins making changes that can improve cardiovascular health, including reductions in carbon monoxide and improvements in heart rate and blood pressure.

People trying to quit can use counseling, nicotine replacement therapy or prescription medication with guidance from a healthcare professional.

Protecting Family Members From Smoke

The secondhand smoke heart risk is particularly important for people who live or work around smokers.

Smoking outdoors and keeping smoke away from enclosed spaces can reduce exposure, but avoiding smoking altogether is the most effective way to eliminate tobacco smoke exposure.

The new research shows that awareness of smoking’s cardiovascular effects remains incomplete. While lung cancer continues to be an important part of tobacco education, the findings suggest that heart attacks, strokes and the dangers of secondhand smoke deserve greater attention as well.