Doctors have warned about medical issues since the 18th century.
Sir Richard Doll started his pivotal work on smoking and lung cancer in 1948. The British physiologist is credited with being the first to prove that smoking causes lung cancer.
The doctor himself gave up smoking two-thirds of the way through his initial study. Though the research met with skepticism at first, it became the foundation for all subsequent research on the subject, as well as the underpinning of the international public health campaign against smoking.
Nonetheless, he wasn't the first doctor to raise the issue. In fact, the medical question was raised within a few decades after smoking became pervasive in England.
During a debate at Oxford on smoking in the early 18th century, opponents produced the blackened brains and charcoal-colored veins of smokers. In 1761, John Hill noted the presence of cancer of the nasal passages in smokers. In the mid-19th century, researchers did serious epidemiological studies.
One researcher noted in the medical journal "The Lancet" in 1857 that perhaps insurers should be asking customers whether they smoked.