In a coho study nonsmokers were found to have carcinoma lung. This indicates-
Coho study is also known as incidence study. The cohos are identified prior to the appearance of disease under investigation. The study group so defined are observed over a period of time to determine the frequency of disease among them. Ref: 25th edition, Park's Textbook of Preventive and Social Medicine, Page no. 83
Smoking does not cause lung cancer
Etiology for lung Ca is multi factorial
Smoking is the only cause of lung cancer
Passive smoking also increase lung cancer
Epidemiology