Over the last sixty years, doctors, scientists, and clinical researchers have established what many observers have long felt was the case: a causal link exists between smoking cigarettes and the incidence of lung cancer. Lung cancer occurs when the cells within the lung tissue are altered at a genetic level to mutate and multiply at an aggressive rate.
The results of many studies on the effects of tobacco have shown that cigarette smoke carries numerous chemicals, called “mutagens”, that cause lung tissue cells to mutate. Substances such as carbon monoxide, hydrogen peroxide, and benzopyrene contained in cigarette smoke affect how cells change and grow.
One of the earliest studies into the relationship between smoking and lung cancer came from the School of Medicine at Washington University in St. Louis. Ernst Wynder, a first-year medical school student, started the first research efforts into the causes of lung cancer in 1948. He examined the cadaver of a man who had died of lung cancer to find that the lungs were blackened. Two years later, he published a study that showed that lung cancer rates were as much as forty times higher in smokers than non-smokers.
Although the link between cigarette smoke and cancer has been understood for decades, the so-called “smoking gun” came to light in 1998. Researchers found out how benzopyrene affects a gene known as “p53”. The gene acts as a screening agent to make sure that healthy cells divide while unhealthy ones die off. In the cases of cigarette smokers, benzopyrene “shuts off” the p53 mechanism, allowing unhealthy and malignant cells to grow and spread throughout the body.
The statistics surrounding the link between cigarette smoking and lung cancer show some startling truths. According to studies conducted by major life insurance firms, the act of smoking a single cigarette can shorten the smoker’s life by ten minutes. By this measure, each pack shortens a smoker’s life expectancy by 3.5 hours. For a two-pack-a-day smoker, that adds up to more than one hundred days per year of reduced life expectancy – more than twenty-eight percent. Over 80 percent of lung cancer cases are attributable to cigarette smoking. Twenty percent of all deaths in the US are tobacco-related.
Smoking in combination with exposure to other carcinogens can raise the risk of lung cancer. Studies have shown that people who were exposed to asbestos fibers in the workplace and who smoke can have over 40 times the risk for developing lung cancer as those who smoke and do not have significant asbestos exposure.