Geographic patterns in county mortality rates from cardiovascular diseases

Age-adjusted mortality rates for coronary heart disease (CHD) and cere-brovascular disease (CVA) were calculated for over 3000 counties In the contiguous United States. Rates were for 35-74-year-old white males and white females for years 1968-1971. Maps by cause and sex displayed patterns similar to those found In 1950 and 1960. For CHD, rates were highest in the southeastern United States while lowest rates were in the Plains and mountain regions. CVA rates for males followed a similar pattern but rates for females showed little clustering. Quantitative assessment was done using a multiple linear regression to predict mortality rates by the latitude, longitude and altitude of the population centrold of the counties. Approximately 30% of the variance was explained for CHD rates for males and females. However, less than 10% of the variance for CVA rates for females could be explained by the final regression equations. Longitude was the largest and most consistent contributor to the regression equations. Variables correlated with longitude in the United States should be considered for possible association with cardiovascular mortality rates.