PATHOPHYSIOLOGY AND NATURAL HISTORY EPIDEMIOLOGY Secular trends in ischemic heart disease mortality: regional variation

We compared secular trends in ischemic heart disease (IHD) mortality in four southeastern states (North Carolina, Georgia, South Carolina, and Virginia) with those in three selected other states (California, New York, and Utah). Mortality data were obtained from U. S. vital statistics and population information from the U. S. Census Bureau. Age-adjusted IHD mortality increased until 1968 in the southeastern states and then declined and declines were greatest in the nonwhite female population. In contrast, IHD mortality in all groups in California and in the female population in New York and Utah began to decline in the early 1950s, with accelerated declines since 1968. In all states the decline in rates in nonwhite populations have been greatest in the younger age groups. This has not been true in the white populations. Declining IHD mortality correlated moderately well with the decline in death from all cardiovascular disease and from all causes, but not with the declining cerebrovascular disease mortality. Respiratory cancer mortality increased in similar proportions in California and South Carolina, two states with dissimilar IHD trends. These findings suggest that improved control of hypertension and changing patterns of cigarette smoking may not be responsible for the recent decline in IHD mortality. Circulation 68, No. 1, 3-8, 1983. THE WELL-PUBLICIZED recent decline in ischemic heart disease (IHD) mortality in this country and in several other western nationsl' has generated much speculation as to its underlying causes and has rekindled interest in the search for the etiology of IHD. Studies of geographic variations in disease-specific mortality have provided useful epidemiologic clues and might help to elucidate the reasons for the recent decline in IHD mortality.4 International studies of secular IHD mortality trends have shown marked geographic variability. While mortality has been declining in the United States, Canada, Australia, Finland, Belgium, and Israel, it has been increasing in Sweden, Denmark, Eastern Europe, and the Soviet Union.2' 7-9 Regional studies in the United States have demonstrated dramatic interstate and From the Department of Pediatrics, Duke University Medical Center, Durham, NC. This work was supported in part by Preventive Cardiology Academic Award grant HL-00633 from the National Heart, Lung and Blood Institute, a Clinical Epidemiology grant from the Andrew W. Mellon Foundation, and Preventive Oncology Academic Award grant CA-00726 from the National Cancer Institute. Address for correspondence: Sue Y. S. Kimm, M.D., Box 3544, Duke University Medical Center, Durham, NC 27710. Received Jan. 18, 1983; revision accepted March 24, 1983. intercounty differences in IHD mortality, as well as a recent concentration of high rates in the southeastern United States. I'll However, no study of regional secular trends has been reported. In the last review of this subject, only data from the years up to and including 1971 were analyzed,14 and most of the decline has occurred since that time.' The first purpose of our study was to examine regional differences in IHD mortality trends in the United States from 1950 to 1976. We also assessed the impact of changing IHD mortality on the rate of death from all cardiovascular disease (CVD) and on the rate of death from all causes. Our second purpose was to investigate some of the hypotheses concerning the reasons for the decline in IHD mortality by studying mortality trends in diseases that share risk factors with IHD. For example, hypertension is known to be a major risk factor for both cerebrovascular disease (CVA) and IHD'6 17 and cigarette smoking is a risk factor for both IHD and respiratory tract cancer."718 We studied trends in CVA and respiratory cancer mortality in an attempt to explore the potential contributions to the decline in IHD mortality made by the decreasing prevalence of uncontrolled hypertension and by changing patterns of cigarette smoking. Vol. 68, No. 1, July 1983 3 by gest on Jne 4, 2017 http://ciajournals.org/ D ow nladed from