Lung function as a risk factor for coronary heart disease

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Probability of middle-aged men developing coronary heart disease in five years

Characteristics of 11,132 men aged 40-59 years and free from coronary heart disease (CHD) at entry were related to follow-up experience, using multivariate analysis. In 5 years among 2,404 U. S. railroad men and 8,728 European men there were 615 cases of CHD, 214 of whom died from CHD or suffered definite nonfatal infarction.

With five entry characteristics (age, systolic blood pressure, serum cholesterol, smoking habit, and body mass index), multiple logistic solutions for Europeans and Americans, separately, gave estimates of the individual probability of CHD. Classified by deciled scores for these probabilities, the expected and observed CHD cases were highly correlated (r = 0.930-0.981). Predictions based on European data applied to Americans, and vice versa, gave similar high correlations but American incidence was excessive compared with European experience.

Application of the analysis coefficients obtained from data in Europe and in the U. S. railroad to 6,221 other U. S. men 40-59 years of age, CHD-free at entry, gave good prediction of relative risk (r = 0.94) for observed versus predicted cases in deciles of risk score; however, the actual numbers of cases were underpredicted.

From single measurements of a few characteristics the multiple logistic solution usefully estimates the relative risk of CHD for individuals. Age, systolic pressure, and serum cholesterol are universally powerful predictors of risk. Variables not measured in this study or not yet identified contribute to the risk of CHD among American men.

Ischaemic heart disease in middle-aged men. Prevalence comparisons in Europe

The authors report the results of a collaborative study of the prevalence of ischaemic heart disease in 6 samples of middle-aged male clerical workers, drawn from 5 European countries and covering in all 4522 subjects. Detailed standardization of data-collection methods and of coding, analysis and tabulation was undertaken.Estimated prevalence rates for angina and history of possible infarction, based on the use of a standard questionnaire, showed significant variation between samples, but the validity of international comparisons of symptoms remains unproven. Prevalence rates for ischaemic-type ECG findings were high everywhere, and mostly showed no significant variation between the groups studied. Central coding of ECG findings proved essential to the making of unbiased comparisons. Neither the prevalence rates for symptoms nor those for ECG findings in these samples were recognizably correlated with the corresponding national mortality rates for ischaemic heart disease.Several possible risk factors were studied, but the only one found to be consistently associated with ischaemic heart disease was a raised blood pressure. Cigarette smoking was strongly associated with bronchitic symptoms and dyspnoea, but an association with heart disease was not demonstrated.