Are geographic variations in death rates for the cardiovascular diseases real?

Regional variation in ischemic heart disease incidence

This study examines the relationship between cardiovascular risk factors and regional variation in IHD incidence among white males 55-74 years of age from the NHANES I Epidemiologic Followup Study. The age-adjusted IHD incidence rate was lowest in the west (31.3 per 1000 persons years of followup). The rates in the northeast, midwest, and south were similar and so they were combined into one region, the non-west, with a rate of 42.4. Differences in risk factors (smoking, educational level, hypertension, serum cholesterol, diabetes mellitus, and body mass index) did not explain the regional differences in IHD incidence. After adjusting for baseline risk factors using proportional hazards model, the risk of IHD incidence was still 38% higher in the non-west compared to the west. However, the effect of hypertension, diabetes, and body mass index on IHD incidence varied by region.

Geographical patterns of heart disease in the Northeastern United States

A 49-county region surrounding the urban corridor from New York through New Jersey to Philadelphia was the focus of an investigation of the spatial patterns of mortality from four types of heart disease: major cardiovascular, acute ischemic, chronic ischemic and cerebrovascular. The data used were age-adjusted mortality rates for white males and white females for the period 1968-1972. Central to the research was interest in the existence of county clusters with similar rates, high and low risk areas and possible associations of mortality rates with environmental and socioeconomic conditions. The tasks completed in this first phase of a projected multi-phase project led to the identification of four country clusters within the region. High major cardiovascular rates appear to make the Southern New Jersey cluster a high risk zone. In contrast, a Central Corridor cluster has relatively low rates for all the diseases. No clear pattern was in evidence for the Northwestern Periphery cluster. Finally, a stark contrast between acute and chronic ischemic rates appeared in the Urban Spur. The next step in this research will be to search for either consistency or deviation from these patterns in the 1973-1976 period. A risk factor data set will be created to analyze the patterns in greater detail.

Heart disease mortality among black migrants: a study of Ohio residents (1960-1967)

In a demographic study, the black Ohio residents were characterized by those born in Ohio and those born in other regions of the United States, and comparisons were made of rates for all deaths (1960-1967) for coronary heart disease (420), endocarditis and myocardial degeneration (421-422), hypertensive cardiovascular diseases (440-447), cerebrovascular diseases (300-334), cardiovascular diseases (400-468), and total diseases of the cardiovascular system (300-334) (400-468). The division of the total United States-born Ohio residents by region of birth provided marked differences in the age-adjusted rates in the relative comparisons. The black males and females born in the South had a markedly higher age-adjusted death rate (ages 45 to 64) than those born in Ohio in each of the categories of cardiovascular diseases studied. For coronary heart disease, the age-adjusted death rate for the black males showed a marked excess over the black females, for each region of birth, whereas for hypertensive cardiovascular diseases the black males and females had similar age-adjusted rates for each region of birth. The findings indicate a carry-over among the black of a higher cardiovascular risk among those born in the South and lend support to the concept of the influence of the endemic factors in the early years of life. In the prospective study of black steelworkers, it was observed that migrant and nonmigrant workers had approximately the same mortality for cardiovascular disease overall, and when specific work areas were considered. Selective factors of employment, of medical screening, and capability of continued employment in strenuous environments, were considered the most likely basis for the similar mortality experience.