Is smoking more harmful than AIDS?

Helmut Schmidt, the former German chancellor, was a notorious chain smoker. So much so that he was known to light up in non-smoking areas and while on live television. Yet he lived to be 96 years old, remaining an active public figure until the end and writing some 13 books after he turned 70.  Did smoking, which he obviously enjoyed so much, not hurt him? 

Schmidt, and others like him, feed a common belief that you can lead an unhealthy life and still live to a ripe old age. Winston Churchill, when asked about the secret of his longevity, famously quipped, “No sports, just whisky and cigars,” to the great delight of generations of bon vivants.

However, those who believe that they can safely follow Schmidt’s and Churchill’s examples make a fundamental mistake called selection bias—they are looking at a subset of people who lived a long life against the odds rather than the many others who passed away before their golden years. Since there are many more elderly people alive today than ever before in human history, you’re also more likely to find cases that enjoy longevity. You will also find elderly folks in Somalia or the Democratic Republic of Congo, but I’m sure you would agree that moving there is probably not a good idea.

Thanks to the Global Burden of Disease database developed by the Institute for Health Metrics and Evaluation (IHME), we can now calculate the statistical impact of health status and risks. Building on the demographic platform, we have mapped the impact of several health variables that can be applied to every person in the world. We can estimate, on average, how many years of life a smoker will lose and how many years they would gain by avoiding the habit. And we can compare the results with (or combine them to) the outcomes of other risks or conditions, such as HIV/AIDS, tuberculosis, malaria, diabetes, or hepatitis. Years of life lost or gained depend on how long you can expect to live in the first place, as well as on the quality of the health system in the country in which you live, as well as your gender.

Here are illustrative results, some of which came as a surprise to the two authors of this blog, a 24-year-old Austrian woman and a 46-year-old German man:

  • If you don’t get treatment, HIV/AIDS kills you quickly, while smoking is slowly fatal. This is why AIDS has a more dramatic effect, no matter the country, because statistically you lose more life years if you die young.
  • As expected, the impact of HIV/AIDS is much more profound in poor countries, not just because it is more common but also because access to treatment is less systematic. A 24-year-old Kenyan woman, on average, would lose 28.2 years of life because of HIV/AIDS; in Austria, the same woman would lose 18.1 years.
  • However, if you are over 40 years old and live in a developed economy you can expect to lose more life years from smoking than from contracting HIV/AIDS. For example, a 46-year-old German man would lose 11.5 years from smoking and 8.3 years from AIDS.

Figure 1: Life expectancy of a 24-year-old Austrian woman

Global_20170327_Life Expectancy Austria

Source: authors’ calculations based on and IHME

Figure 2: Life expectancy of a 46-year-old German man

Global_20170327_Life Expectancy Germany

Source: authors’ calculations based on and IHME

Of course we never know how long we will actually live, how medicine will evolve, and where we will ultimately be living. But those who believe their lifestyle doesn’t matter should think twice. The extra satisfaction you get today by indulging in habits such as smoking comes at a higher price than you think—precious additional years you could spend with your grandchildren or writing the memoirs of a long and well-lived life.