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Smoking cigarettes is widely associated with lung cancer, but its effects extend throughout the cardiovascular system, increasing the risk of heart disease, heart attacks and strokes. A recent international study has highlighted a significant gap in public awareness of these dangers, particularly the cardiovascular consequences of secondhand smoke.
The study, published in BMJ Open, examined information from two major international tobacco surveys covering 46 countries. Researchers analysed responses from adults who smoke and asked whether they understood the links between smoking and several serious health conditions, including lung cancer, heart disease, heart attacks and stroke.
More than nine in ten participants, about 92 percent, understood that smoking could cause lung cancer. Awareness was considerably lower when participants were asked about cardiovascular disease. Depending on the survey analysed, between 85 percent and 80 percent recognised the connection between smoking and heart disease or heart attacks. Awareness of the relationship between smoking and stroke was lower still, ranging from 66 percent to 75 percent.
The knowledge gap became even more pronounced when participants were asked about secondhand smoke. While between 77 percent and 82 percent knew that exposure could cause lung cancer, only between 62 percent and 73 percent understood that secondhand smoke could contribute to heart disease or heart attacks.
Researchers also found little improvement in public understanding over time. Across the five health effects examined, average awareness increased by only about 0.14 percentage point annually.
Smoking contributes significantly to cardiovascular disease because cigarette smoke contains substances that interfere with normal blood circulation. Nicotine can increase heart rate and blood pressure, while carbon monoxide reduces the amount of oxygen carried by the blood. Smoking can also make blood more likely to clot and contribute to narrowing and stiffening of blood vessels.
These effects can increase the likelihood of a heart attack, particularly when a clot blocks an artery supplying the heart. Similar processes can contribute to an ischemic stroke when blood flow to part of the brain becomes blocked.
Secondhand smoke presents another serious concern because people nearby inhale many of the same toxic substances. Exposure can damage blood vessels and increase inflammation, contributing to cardiovascular disease even among people who do not smoke.
The study cited estimates that smoking contributed to about 2.6 million deaths from heart disease and stroke worldwide in 2019. Secondhand smoke was estimated to have caused approximately 1.3 million deaths among nonsmokers in 2021.
Health experts emphasise that reducing cigarette consumption is not equivalent to eliminating cardiovascular risk. Quitting completely provides the greatest benefit, with improvements beginning after cessation. People who smoke can seek medical support through counselling, nicotine replacement therapy and other approved treatments.
The findings underline the importance of understanding that cigarettes do not only threaten the lungs. Their effects can reach the heart, brain and blood vessels, while exposing those nearby to preventable health risks.
