Eat plenty of fruit and vegetables, exercise regularly and don’t smoke – probably the three most common health messages we all hear. The fact that tobacco smoking is a major risk factor for lung cancer – and countless other diseases – is now so widely accepted that it is difficult to imagine a time when doctors actually recommended smoking to their patients. But how did the tide begin to turn?
As recounted in a 2013 article commemorating the 50th anniversary, then-U.S. Surgeon General Luther L. Terry released a landmark report in 1964 stating that cigarette smoking caused lung and laryngeal cancer. Terry went even further, noting that there is growing evidence of a link between tobacco use and other conditions, including emphysema, heart disease and other types of cancer.
At the time, more than half of American men and more than a third of American women were active smokers. Most of us can’t remember or imagine a time when lighting in a busy office or on an airplane was completely normal. But even centuries before that, some began to wonder whether smoking would cause invisible damage to our health.
Early evidence of the dangers of smoking
One of the first publications linking tobacco to poor health dates back to 1602. According to Cancer Council New South Wales, the anonymous English author of the essay suggested that tobacco smoke could have similar effects to the soot produced by chimney sweeps. were exposed to and caused well-documented occupational diseases.
Over the next few centuries, there were a handful of others who tried to warn people about the potential dangers of pipes, cigars, and eventually cigarettes, but few gained any traction among the general public. It wasn’t until the 20th century, the number of lung cancer cases began to increase significantly, and the number of medical reports pointing the finger at tobacco became increasingly difficult to ignore – but that’s not for lack of trying.
For fear of incurring the wrath of Big Tobacco and losing a lot of advertising revenue, newspaper editors in the early and mid-20th century were a bit nervous about publishing anti-smoking articles. A debate also raged within the medical community, with many finding it difficult to accept the growing body of evidence and struggling to understand why not everyone who smoked heavily seemed to have health problems.
Thus, even as more and more reports were released in the 1940s and 1950s, anti-smoking efforts in the US were largely led by health care nonprofits rather than legislators, and many in the general public remained unaware of the dangers.
It would seem totally bizarre to us today to use a doctor and athletes to advertise cigarettes, as in this 1939 example.
Image credit: Wellcome Collection (public domain)
The scientific case
Human studies
Let’s go back to the 1920s and 1930s, and the increase in lung cancer cases that people began to see. It is only thanks to the burgeoning field of epidemiology that this trend was noticed at all – and in turn, lung cancer research has helped strengthen some of the epidemiological techniques still used today.
In 1939, German researcher Franz Hermann Müller conducted an important case-control study. These studies are a mainstay of health research today and compare two cohorts of people: the patients, who all have a particular disease or condition, and the controls, who are as similar as possible to the cases but, crucially, do not have the disease. .
Although not a perfect study, the article was undoubtedly significant and concluded that smokers were more likely to develop lung cancer than non-smokers. Later similar studies showed the same thing, but an important thing to note about these types of studies is that they cannot prove causality – there was no reason to believe that the smokers did not get lung cancer more often due to simple chance. , or some other unknown factor.
However, as we entered the 1950s, more and more data added even more weight to the idea that smoking was bad news for health. Crucially, cohort studies were also launched. These studies follow a group of people over a period of time and track their habits and health outcomes to spot trends. There was mounting evidence that smokers had worse health outcomes than their non-smoking counterparts.
Animal studies
As science historian Dr. Robert Proctor points out in a 2011 article, animal data also played a key role in accumulating evidence linking smoking to cancer. Pioneering Argentine cancer researcher Ángel H. Roffo showed that tobacco smoke was carcinogenic when applied to the skin of rabbits. Similar experiments were later repeated with mice and received widespread media attention, with the public backlash prompting tobacco companies to make increasing efforts to change the narrative.
And honestly, it worked, at least for a while. The mouse research came out in the 1950s and smoking didn’t reach its peak in the US until the mid-1970s.
Other research
In addition to the human and animal evidence, other damning scientific data began to pile up.
As Proctor explains, observations of lung cells in the laboratory had shown how cigarette smoke can damage cilia, tiny hair-like structures that line the airways and move mucus and trapped particles – like the nasty components of cigarette smoke that you really don’t. I don’t want to hang out there.
And in what could be considered one of the final nails in the coffin, remember those chimney sweeps? Well, in the 1930s, people discovered that a class of chemicals called polycyclic aromatic hydrocarbons, found in tar, was the main cause of their problems. It wasn’t long after that others, including Roffo, noticed that the same chemicals were present in tobacco smoke, giving us a plausible mechanism by which smoking could cause cancer.
Where are we now?
Things reached a tipping point in the 1960s. Health associations in the US lobbied President Kennedy to open a presidential commission to investigate the tobacco problem, eventually leading to the 1964 Surgeon General’s report, in which we began this tour of part of the history of smoking science.
Nowadays we are more accustomed to seeing strongly worded warning labels on cigarette packs.
Image credit: Valkantina/Shutterstock.com
The World Health Organization says tobacco kills more than 8 million people around the world every year, both directly and through passive smoking. Today, global smoking trends show a mixed picture, with some places banning tobacco while others scrap similar plans. But the fact that smoking increases the risk of cancer is no longer disputed, and continues to inform campaigns that try to raise awareness of the danger and encourage people to quit for good.