British Doctors Study
Some data from a survey of British doctors (Doll and Peto, 1976, BMJ) are presented in Table 1. In brief, in 1951 all resident men and women on the British Medical Register were sent a questionnaire requesting information about their smoking habits. With few exceptions, all men who replied were followed for 20 years (questionnaires asking about changes in smoking habits were sent in 1957, 1966, and 1972, and causes of death were recorded).
Table 1 - Ischaemic Heart Disease (IHD) mortality in non-smokers and current cigarette smokers, by age
IHD Annual death rates per 100,000 men
Current cigarette smokers: number per day
Non-smokers
Age (years) 1-14 15-24 25-44 45-54 55-64 65-74 75+
<45 7 46 61 104
45-54 118 220 368 393
55-64 531 742 819 1025
65-74 1190 1866 1511 1731
>=75 2432 2719 2466 3247
a) Calculate the age-specific rate ratios for smokers compared to non-smokers.
b) Describe the rate ratio pattern, and any conclusions you might draw.
c) What else would you like to know?
