Is smoking five cigarettes a day any better than smoking 20? Is puffing on a cigar less harmful than having a cigarette? What about chewing tobacco—healthier than smoking it? According to a large new study in the journal Lancet, the answer to all these questions is: not really.

Led by researchers at McMaster University in Ontario, Canada, an international team of scientists recruited more than 27,000 volunteers in 52 countries to assess the impact of tobacco exposure—including smoking, chewing and secondhand inhalation—on heart attack risk. Overall, researchers found that tobacco use of any kind was significantly more harmful than not using it at all.

According to the study, current smokers were on average about three times more likely to have a heart attack than nonsmokers, and that risk increased more than 5% with every additional cigarette smoked per day. People who smoked more than a pack a day had four and a half times the risk of heart attack as nonsmokers; those who smoked fewer than 10 cigarettes a day were better off, but they still had 63% more heart attacks than people who never smoked regularly in their lives. And for heavy-duty, two-pack-a-day smokers, the risk of heart attack was more than nine times greater.

If you chew tobacco instead of smoking, you’re still more than twice as likely to suffer a heart attack than your peers who don’t use tobacco at all. If you smoke pipes, cigars or bidis (small filterless cigarettes rolled in temburini leaves and tied with a string—smoked mostly in India and other parts of Southeast Asia), your heart-attack risk is between 2.9 and 3.3 times higher than average.

Lending credence to widespread smoking bans in bars, restaurants and other public places, researchers found that secondhand-smoke exposure also contributed to elevated heart attack risk. People with the lowest levels of exposure in the study—between 1 and 7 hours per week—had 24% more heart attacks than those who never breathed secondhand smoke. As exposure to secondhand smoke increased, so did heart attack risk: people who were around cigarette smoke more than 21 hours a week, were 62% more likely than average to have a heart attack. That’s about as bad as smoking nearly half a pack a day.

What It Means: It’s easier said than done, but the take home message is simple and familiar: don’t smoke. In fact, don’t use tobacco in general.

The good news is that for many smokers the benefits of quitting are profound and relatively quickly achieved. Three to five years after quitting, the heart attack risk in light smokers—those who had less than half a pack a day—was the same as if they’d never smoked at all. In moderate to heavy smokers the benefits were significant, if not quite as spectacular: on average, three years after giving up tobacco, smokers’ heart attack risk was reduced some 40%. Twenty years after quitting, however, that risk remained 22% higher than that of the nonsmoking population.

From the Archive:
June 30, 2006: Blinded By Lights (Cigarettes, that is)
Nov. 20, 2005: Smoke Free