The association between mortality from ischaemic heart disease and mortality from leading chronic diseases.

AIMS Coronary risk factors raise the risk of other chronic disorders. We therefore tested the hypothesis that the geographic distribution of ischaemic heart disease mortality is associated with that of other chronic diseases with which it shares risk factors. METHODS AND RESULTS For the 50 provinces of Spain, we collected mortality data for the period 1980-1995 from the national vital statistics. We calculated age-adjusted mortality rates for the leading causes of death in quintiles of provincial distribution of ischaemic heart disease mortality, and correlation coefficients with respect to provincial ischaemic heart disease mortality. As expected, because they share risk factors with ischaemic heart disease, mortality from cerebrovascular disease, malignant tumours, lung cancer, respiratory diseases, chronic obstructive pulmonary disease, diseases of the digestive system, cirrhosis of the liver and all causes, increase with the rise from lower to higher quintiles of ischaemic heart disease mortality. Ischaemic heart disease mortality registered correlations over 0.5 (P<0.001) with mortality from many of the above diseases in the periods 1980-1984 and 1991-1995. Expectations were similarly borne out for disorders not sharing risk factors with ischaemic heart disease, in that mortality from prostate and breast cancer, injury and poisoning, traffic accidents and ill-defined causes in most cases did not show a provincial association with ischaemic heart disease mortality. In general, these results were observed for both sexes and across all age groups. CONCLUSION Ischaemic heart disease mortality is associated with mortality from chronic diseases which share coronary risk factors, across provinces of Spain over the period 1980-1995. This suggests that the geographic variation in such chronic diseases is due to common factors, potentially susceptible to similar preventive interventions.