'Best to stop smoking, but fewer cigarettes help'

A 40-year study conducted by Tel Aviv University researchers has proven that giving up smoking lowers the risk of disease, increases life expectancy and improves the quality of life. But while complete cessation is preferable, those who claim to be unable to kick the habit enjoy health benefits from lowering their cigarette consumption, the study showed.

Vicki Myers, a researcher at TAU’s Sackler Faculty of Medicine, and Dr. Yariv Gerber and Prof. Uri Goldbourt of TAU’s School of Public Health examined survival and life expectancy rates of smokers who reduced their cigarette consumption instead of quitting entirely. Their data covered an unusually long period of more than four decades.

While quitters were found to have the biggest improvement in mortality rates – a 22 percent reduced risk of an early death, compared to smokers who maintained their smoking intensity – reducers also saw significant benefits, with a 15% reduced risk. These results show that smoking less is a valid risk-reduction strategy, Myers said, adding that formerly heavy smokers had the most to gain from smoking reduction.

This research has just been published in the American Journal of Epidemiology. To examine the impact of changes in smoking intensity over time, the researchers drew on a sub-cohort of the Israeli Ischemic Heart Disease Study, comprising a database of 4,633 working Israeli men, all smokers at baseline, with a median age of 51 at recruitment. Interviews regarding their smoking habits took place in 1963 and again in 1965, and participants’ mortality status was followed for a period of up to 40 years.

During their first interview, participants were placed in categories by daily cigarette consumption – no cigarettes, one to 10 cigarettes, 11 to 20 cigarettes and more than 21. In the second interview, researchers noted whether an individual had increased, maintained, reduced or ceased smoking during the intervening two years, with “increasing” or “reducing” defined as moving up or down at least one category of cigarette consumption within this range.

Unsurprisingly, quitters were the best off in the long term, with a 22% reduction in overall mortality. Those who reduced their smoking by one category or more were seen to have a 15% decrease in overall mortality risk and a 23% reduced risk of cardiovascular mortality.

In addition, the researchers measured the participants’ survival to the age of 80. Quitters saw a 33% increased chance of survival to 80 years of age, and reducers a 22% increased chance.

Myers says that their study, one of the few to take smoking reduction into account, shows that reduction is certainly better than doing nothing at all. She credited the long-term follow- up period for demonstrating the effect of smoking reduction where other studies have not, because damage done by smoking, and subsequently the recovery process, has a long time line.

One of the important lessons of their study, said Myers, is that it is never too late to tackle your smoking habit. Participants of this study, who were on average 50 years old when the study began, were still able to quit or reduce their smoking and see long-term benefits from their efforts. Though reduction is a controversial policy – some health professionals believe it dilutes the message of cessation – smokers should take any steps possible to improve their long-term health, she advised.