A study was initiated in 1970 with a population of 5000 adults. They were enquired about their drinking habits to study the relationship of alcohol consumption to the subsequent occurrence of cancer. The study was planned for 20 years till 1990-1995. This is an example of what type of epidemiological study?

This is an example of a current coho study or a prospective coho study as it proceeds from cause to effect. In this type of study incidence can be calculated. A prospective coho study is one in which the outcome (e.g. disease) has not yet occurred at the time the investigation begins. It is also called longitudinal study, incidence study or forward-looking study. Ref: Park's Textbook Of Preventive And Social Medicine, By K. Park, 19th Edition, Pages 65, 66, 70, 71.