Smokers who have reduced their habit to two to five cigarettes a day may be discouraged to learn that they still have twice the risk of developing heart disease than people who don't smoke at all, according to new research.
The study, published Tuesday in PLOS Medicine, also found that people who have dramatically reduced their smoking to five or fewer cigarettes a day are 60% more likely to die of any cause than people who have never smoked at all — and it may take at least 30 years for their bodies to rebound.
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"Even we were surprised by the strength of harm from even a low quantity of cigarettes, and the incredible importance that quitting early had on long-term heart health," said Dr. Michael Blaha, the study's author and a lead investigator for the American Heart Association's Tobacco Center for Regulatory Science.
The findings come at a time when cigarette use is falling in the United States. Still, use of tobacco products, including cigarettes, persists as the leading cause of preventable death and disease, the Centers for Disease Control and Prevention says.
The study used data from 22 previous studies involving more than 320,000 adults, mostly in the United States, comparing health risks and outcomes for people who smoked and people who didn't. These studies were all long-term, following participants for 20 years.
Blaha and his colleagues used the data to analyze the impact of smoking duration, as well as cessation, on risks for heart attack, stroke, heart disease, heart failure and atrial fibrillation. They also looked at deaths from coronary heart disease, cardiovascular disease and all causes
Smoking 11 to 15 cigarettes a day – less than a pack, which has 20 – was linked to an 84% higher risk of heart disease and double the risk of death from any cause, according to the study.
Previous research concluded that it took former smokers 2 to 29 years to reach the same risk levels for heart disease and death as people who had never smoked. But the new study found this may take as long as 31 to 40 years.
"The message here is clear — don't smoke — and for those who do, quit early in life and strive to quit entirely versus smoking less, because even occasional use of tobacco has substantial health consequences," said Dr. Stacey Rosen, volunteer president of the American Heart Association and executive director of the Katz Institute for Women’s Health of Northwell Health in New York City.