Mortality in Relation to Smoking: Ten Years' Observations of British Doctors

The mortality of nearly 41000 medically qualified men and women in the United Kingdom has been observed for twelve years. During the first 10 years 4597 of the men and 366 of the women died. These deaths have been analyzed in relation to the smoking habits reported by doctors in reply to a questionnaire dispatched to them in 1951 (both sexes) and again in 1957 and 1960. An association with smoking is found in differing degrees in men for seven causes of death and no association was found with the remaining 61% of the death rate and this includes such major causes as other forms of cancer cerebrovascular accidents hypertension myocardial degeneration suicide and accident. A linear rise of death rate was observed from nonsmoker to light medium and heavy smokers which indicates that there is no smoking threshold which must be reached before the death rate from cancer of the lung shows a response. The death rate continues to fall step by step the longer smoking has been given up. Whether smoking acts synergistically with air pollution upon the respiratory tract is not known. Some suggest a reasonable conclusion that cigarette smoking is one of the more important etiological factors in chronic bronchitis in Great Britain and relying on clinical evidence it could be said that possibly chronic bronchitis itself plays a part in producing cancer of the lung. Tobacco and alcohol play some part in the production of cancers of the upper respiratory and digestive tracts. Excess mortality due to coronary disease without hypertension is limited to cigarette smokers which is marked at under age 55 but disappears at over age 75. Evidence supports the claim that cigarette smoking is one of the causes of coronary thrombosis under age 75. Continued smoking may prevent or delay the healing of a chronic gastric ulcer and thereby it may increase the mortality rate. Mortality from alcoholism and cirrhosis of the liver is specially high in heavy smokers. There appears to be no cause of mortality which is lessened by smoking.