A survey of 12,000 professional men in 14 occupational categories was conducted to determine the interrelationship among smoking habits, occupation-related emotional stress, and coronary heart disease prevalence. The distribution of the disease among professional groups in the United States showed a marked gradient which was unassociated with heredity or diet but strikingly related to the relative stressfulness of occupational activity. This increase in prevalence rate with advance in stress was shown to be remarkably consistent by age. Smoking was not only found to be stress-related but also statistically correlated with the reported frequency of ischemic heart disease in these professional groups. An entirely unexpected finding was the higher prevalence of coronary heart disease among nonsmokers (6.54%) than among exsmokers (2.34%). This paradox casts doubt upon the alleged role of smoking in the genesis of coronary heart disease and adds further emphasis to the probable influence of emotional factors in its causation.
Russek HI. Stress, Tobacco, and Coronary Disease in North American Professional Groups. JAMA. 1965;192(3):189-194. doi:10.1001/jama.1965.03080160009002