A disadvantage is that people s memories may not be accurate. Prospective studies are also called cohort studies. An advantage of this method is that it does not depend on peoples memories which can produce recall bias. The disadvantages of cohort studies are that they are very slow and expensive since people are followed for decades. Identifying the causes Lung cancer.
Lung cancer is the most common cancer world-wide.
Cohort studies have confirmed that cigarette smoking causes lung cancer. These studies have shown that age-specific incidence rates of lung cancer depend not only on the amount of cigarette consumption but also on the number of years smoking. The tobacco industry responded to the evidence of the carcinogenic effects of cigarette smoking by lowering the tar and nicotine content in cigarettes. Although cigarette smoking is considered the main cause of lung cancer, exposure to other substances can significantly raise the risk of lung cancer in certain industrial occupations. These substances are asbestos, polycyclic aromatic hydrocarbons, and radon gas.