While it is better to cut down than to smoke heavily, the study contradicts the common belief that cutting way down also reduces risk quite a bit. In fact, cutting back from a pack a day to just one cigarette a day only lowers the heart health risks a little bit, Allan Hackshaw at the UCL Cancer Institute at University College London and colleagues found.
“We have shown that a large proportion of the risk of coronary heart disease and stroke comes from smoking only a few cigarettes,” Hackshaw’s team wrote in the British Medical Journal’s online publication The BMJ. This has important consequences for smokers who believe that light smoking carries little or no harm.
Hackshaw’s team went back through all the credible health studies they could find dating back to 1946. They looked at how many cigarettes people reported smoking and looked at what happened to those smokers. For men, smoking one cigarette a day on average raised the risk of heart disease by 48% over a non-smoker, while smoking 20 cigarettes a day doubled the risk. For a woman the risks were even higher. Smoking one cigarette a day raised heart disease risk for women by 57% and 20 cigarettes a day raised the risk 2.8 times. Men who smoked one cigarette per day did not have 1/20th the risk — one half of 1% — compared to a pack-a-day smoker, but instead had 46% of the extra risk of heart disease. The conclusion from Hackshaw’s team is that no safe level of smoking exists for cardiovascular disease.
“The take-home message for smokers is that any exposure to cigarette smoke is too much,” Kenneth Johnson, an epidemiologist at the University of Ottawa who was not involved in the research, wrote in an editorial. “New tobacco products, such as e-cigarettes and heat-not-burn cigarettes, may carry substantial risk for heart disease and stroke,” Johnson added. It is still worth trying to cut back, said Paul Aveyard of the University of Oxford, who also was not involved in the study.
“This well-conducted study confirms what many epidemiologists have suspected but few among the public have: light smoking creates a substantial risk for heart disease and stroke. The implication is obvious — anyone who smokes should stop,” Aveyard said.
A new report released last week from the National Academies of Science, Engineering and Medicine found little evidence about the health risks of e-cigarettes but said they might be useful if used to help smokers cut down or quit. Smokers should quit instead of cutting down, using appropriate cessation aids if needed, to significantly reduce their risk of heart disease and stroke. Heart disease is the leading cause of death in the US and most developed countries, and it is estimated that smoking is a key trigger for heart disease deaths.
