Epidemiology

Lung cancer is responsible for more deaths than any other cancer, accounting for 1.2 million deaths per year worldwide. There were over 38,000 new cases of lung cancer (23,245 men and 15,165 women) diagnosed in the UK. Some of the highest incidence rates of lung cancer for both men and women are found in the Merseyside region of the North West of England. The Liverpool Lung Project will use risk factors identified by molecular genetics and epidemiology to define individuals most at risk of developing lung cancer. Several factors can increase the risk of lung cancer

Smoking

Use of tobacco products and in particular cigarette smoking, are responsible for the majority (80-90%) of lung cancer cases. A lifetime smoker has a 20 to 30-fold increased risk of developing lung cancer compared to a lifetime non-smoker. The smoking associated risks are dependent on the age of starting to smoke and the level and duration of smoking. Stopping smoking at any age lowers the risk of lung cancer.

Passive smoking

People who don’t smoke but breathe the smoke of others also have a higher risk of lung cancer. Several studies have found an increased risk of lung cancer in nonsmokers married to smokers compared to nonsmoking households. Workers exposed to tobacco smoke in the workplace are also at greater risk of developing lung cancer.

Occupational exposure

Apart from cigarette smoking, most other risk factors for lung cancer have been identified in occupational settings. As a result, occupational exposure to certain substances (e.g. asbestos, arsenic, ionizing radiation, chromium, nickel), working in certain occupations (e.g. roofers, insulators, foundry workers, coke oven workers) and branches of industries (e.g. shipyards, asbestos production) have been associated with a well-established increased risk of lung cancer.

Air pollution

Over 40 compounds considered to be carcinogenic or probably carcinogenic are found in air pollution. On the basis of large cohort studies in the United States and Europe, there are reasonable grounds for concern that air pollution may increase lung cancer risk, especially in combination with other known risk factors, such as active and passive smoking and occupational exposures.

Diet

Some reports suggest that a diet low in fruits and vegetables may increase the risk of lung cancer if you are exposed to tobacco smoke. Evidence is growing that fruits and vegetables may provide a protective effect against lung cancer.

Medical History

A history of pre-existing respiratory disease (i.e. chronic obstructive pulmonary disease, tuberculosis, bronchitis, emphysema and pneumonia) appears to increase the risk of developing lung cancer. These diseases often cause scarring on the lung, which in turn increases the risk of developing lung cancer.

Family History

Family studies have shown a two to three fold increase in risk in non smokers who have relatives with lung cancer compared to non smokers with no family history. While a shared environment may partly explain familial lung cancer risk, genetic factors may also be important in determining lung cancer susceptibility.

Genetic Susceptibility

It is now well established that people differ in their susceptibility to lung cancer thus suggesting a strong genetic component for the disease. Studies of genetic susceptibility in the Liverpool Lung Project involve investigating polymorphisms in genes implicated in the major pathways of lung carcinogenesis.