British Doctors Study

The British Doctors Study ( German: " British doctors study" ) is the name of a prospective epidemiological study, which ran from 1951 to 2001 and in 1956 provided convincing statistical evidence that tobacco smoking increases the risk of lung cancer.

The study was initially conducted by the famous epidemiologists and statisticians Richard Doll and Austin Bradford Hill. 1971 came Richard Peto them.

Context

Although there was already a suspicion that smoking and various diseases have a relationship, evidence of such a link were very sketchy. In fact, smoking has long been touted as "healthy", and there was no convincing explanation as to why lung cancer rates skyrocketed.

The study, incidentally, was the first statistically reliable medical examination, which was held to statistical criteria. Previously there were only initiated by Ronald Aylmer Fisher studies in agriculture.

The study

In October 1951, the researchers sent all registered male doctors Britain a questionnaire about their smoking habits and their health. Two-thirds, namely 34,439, responded to the request. Apart from these physicians no other groups have been investigated.

The study participants were then based on various criteria - such as the decade of birth, cause-specific death, the health well-being and smoking habits - classified. New questionnaires in 1957, 1966, 1971, 1978, 1991 and 2001 mailed to the study participants.

Statistical Analysis

The return of completed questionnaires was quite high, adequate statistical analyzes enabled. Already in the 1950s was thus demonstrated that both lung cancer and coronary thrombosis (former term for myocardial infarction) occur more frequently significant in smokers than in nonsmokers.

In the following reports, which were published every ten years, more information has been disclosed. In summary, the long-term study showed that:

• Smoking reduces the average lifespan by up to ten years
• 50 percent of all smokers die of a disease associated with smoking, although the earlier time of death of the extent of smoking depends
• Who until the age of Smokes 30 years, does not die earlier
• Smokes 40 years dies an average of a year earlier
• Smokes 50 years, lives on average four years less long
• Smokes 60 years, loses 7 years of life.
• Smokes 70 years, loses 10 years of age.