Smoking just one cigarette per day—as opposed to 20, the average number in a pack—still raises your risk of heart disease and stroke, according to new research published in The BMJ, the British Medical Journal’s online publication.
Heart disease is the leading cause of death for men and women in the United States, according to the U.S. Centers for Disease Control and Prevention.
The findings counter the belief that smoking fewer cigarettes may reduce risks associated with smoking. “Reducing consumption might be expected to reduce harm in a proportionate way—that is, that smoking one instead of 20 cigarettes per day has about one twentieth (5%) of the risk,” according to a team of researchers led by Alan Hackshaw, a professor of epidemiology and medical statistics at the UCL Cancer Institute at University College London. This, however, is not the case in terms of cardiovascular risks.
“What’s clear is that people who only smoke say one—one, two three—cigarettes per day, instead of having that risk as one twentieth compared to somebody who smokes 20 a day, it’s much higher than one twentieth,” Hackhaw said in an interview.
A man who smokes only one cigarette daily, as opposed to a pack of 20, may think that he is cutting his risk of heart disease and stroke to 5% relative to a pack-a-day smoker. However, the risk is actually closer to 46% for heart disease and 41% for stroke, relatively speaking.
For women who smoke one cigarette daily, the excess risk for heart disease is 31%, while the excess risk for stroke is 34%, compared to those who smoke 20 daily.
Prof. Hackshaw’s team reached its conclusion by analyzing 141 individual studies from 55 publications between 1946 and May 2015 that dealt with smoking and cardiovascular disease.
The researchers also compared those who smoke one cigarette per day to those who never smoke. Men who smoke one cigarette daily raise the likelihood of heart disease 48% higher, and the possibility of stroke is 25% higher than those who never smoke.
Women who smoke one cigarette daily have a 57% higher risk for heart disease and 31% higher risk for stroke than women who never smoke.
This is not to say that people s shouldn’t try to cut back on smoking; there are benefits—particularly with the risk of lung cancer—the researchers note.
However, “no safe level of smoking exists for cardiovascular disease,” the team wrote. “Smokers should aim to quit instead of cutting down to significantly reduce their risk of these two common major disorders.”
You can listen to an interview with Prof. Hackshaw below: