Along with the pleasures of smoking there are real risks of serious diseases such as lung cancer, respiratory disease and heart disease, and for many people, smoking is difficult to quit.
An understanding of the health risks of smoking are derived from epidemiology. Epidemiology is a statistically based science, dealing with risks among large groups of people, rather than with individuals. Through questionnaires and observations of people, epidemiological studies can identify the incidence of disease in a given group, such as smokers, and compare it with the incidence in another group, such as non-smokers.
Over many years, these studies have consistently reported a much higher incidence of certain diseases among smokers compared with non-smokers. The studies also report that the risks are reduced after quitting and that quitting earlier has by far the best effect on reducing risks.
Traditionally, epidemiology has been used to identify associations that point to possible causes of a disease, providing direction for thorough laboratory investigations. With smoking, the many laboratory investigations over the years have proved more problematic. To date, scientists have not been able to identify biological mechanisms that can explain with certainty the statistical findings linking smoking and certain diseases. Nor have they been able to clarify the role of particular smoke constituents in these disease processes.
This means that it is not yet possible to determine which smokers will get a smoking-related disease and which will not. Nor can it be determined whether any individual became ill solely because they smoked. This is, in part, because all the diseases that have been associated with smoking also occur in life-long non-smokers.
That said, the studies leave no doubt that smoking is a cause of serious disease, including lung cancer, emphysema, chronic bronchitis and heart diseases.
Our own work for many years has included, and continues to include, research into the assessment of potentially less harmful cigarettes and alternative nicotine products.
For more about our research efforts see Harm reduction.