By now it should hardly be a news flash that smoking is bad for your health. What is interesting, however, is that the risks associated with smoking are getting worse over the last half century. For most of this time the health risks from smoking were greater among men than women – because men smoked more. However, a new study published in the New England Journal of Medicine, indicates that women have essentially caught up to men in this regard (probably not a form of equality they were hoping for).

The article traces trends in smoking-related health risks over the last 50 years. To summarize the finding – smoking increases the risk of developing heart disease, lung cancer, strokes, and chronic obstructive pulmonary disease (COPD). Those first three conditions are the number one, two, and three causes of death respectively (well, cancer in general, not specifically lung cancer). The new study tracks the relative risk of dying from all causes among current smokers and those who have never smoked. For lung cancer specifically they found:

For women who were current smokers, as compared with women who had never smoked, the relative risks of death from lung cancer were 2.73, 12.65, and 25.66 in the 1960s, 1980s, and contemporary cohorts, respectively; corresponding relative risks for male current smokers, as compared with men who had never smoked, were 12.22, 23.81, and 24.97.

So the relative risk for women lagged behind that for men. This risk peaked for men in the 1980s, but women have now caught up. To put the current relative risk into better perspective – those people who are lifelong smokers live on average one decade less than those who have never smoked – 10 years of lost life. This, of course, is an average. You may get lucky and beat the odds, or you may die in your 40s and lose 30-40 years of life. That’s a game I would rather not play.

Why is smoking more risky now than it was in the 1950s? It likely has to do with smoking behavior and trends in the formulation of cigarettes. Smokers over the years have generally started smoking earlier and smoke more.

More interesting, however, is the fact that cigarettes now are often formulated to be low tar, “light” or “mild.” This has two potential effects. The first is to lull smokers into a false sense of security. It’s like overeating fat free ice cream. They think they are smoking less dangerous cigarettes so they smoke more. This, it turns out, is a bad idea. But further, the milder tobacco smoke is less irritation, which means that smokers can inhale the smoke more deeply into their lungs. Further, they have to inhale the smoke more deeply in order to absorb the same amount of addictive nicotine. So light cigarettes may in fact be more dangerous.

One curious fact to come out of this data is that male smokers continue to have a rising risk of COPD. The exact cause is unknown, but it may be related to the deeper inhalation of smoke with current types of cigarettes.

There is a carrot to this stick, however. Quitting smoking, at any age, is beneficial. If you quit smoking before age 30 all of the relative risk of dying essentially goes away. If you quit before age 40 you only lose, on average, one year of life (instead of 10). The later you quit the lower the benefit, of course, but at any age quitting smoking reduces the relative risk of dying. So if you are a smoker – quit now.

Further, laws to discourage smoking are actually working. I remember back in the 1980s there was vigorous debate about laws restricting the places where people could smoke, and smokers were complaining about their rights. I never bought such arguments – I always felt that my right not to be exposed to smoke in public was greater. When data started coming out on the risks of second hand smoke this tipped the scales, and suddenly restrictive laws started popping up.

There is still debate about the relative risk of second hand smoke (it’s real, the question is one of magnitude) but meanwhile that debate has been rendered moot as data comes in showing that restrictive laws help smokers and those around them. A recent study out of the UK, for example, showed a 12% drop in asthma hospital admissions among children following laws to restrict smoking in enclosed public places. In response to such laws smokers are smoking less at home as well, it seems.

Also, laws restricting smoking in the work place have resulted in fewer admissions for myocardial infarctions (heart attacks), including among non-smokers, suggesting a second-hand smoke effect. Such laws reduce public smoking, public exposure to second-hand smoke, and also private smoking. The immediate result is fewer heart attacks and fewer asthma admissions, but we should also expect long term benefits to reduced smoking-related health risks.

Conclusion

If you are a smoker – quit. Seriously, what are you waiting for?

Laws restricting public smoking are a good thing.

And finally, to quote the NEJM article: ““women who smoke like men die like men.”