The decline in stroke mortality: an analysis of temporal patterns by sex, race and geographic region
Introduction: While stroke mortality rates have declined rapidly over the past 30 years, the decline has slowed to a plateau. Herein, we: (1) assess if the race-sex-regional groups have participated equally in this decline, (2) assess if there are race-sex-regional groups where stroke mortality rates continue to decline (i.e., regions or groups not at plateau), and (3) predict how stroke mortality rates will differ by race, sex, or region in the future. Methods: Data on stroke mortality between 1968 and 1996 from the Compressed Mortality File were analyzed in a three-step procedure: (1) “crude” age-adjusted stroke mortality rates were calculated by race and sex at the county level, (2) these rates were “smoothed” across the counties and years, and (3) a model was fit to describe the temporal pattern of mortality rates by county. The following parameters were then calculated: (1) the percent decline in stroke mortality between 1968 and 1996, (2) the anticipated percent decline to the “floor” for stroke mortality rates, and (3) the anticipated floor of the stroke mortality rates. Results: Race/sex specific maps show the geographic variations in the above parameters, and indicate substantial differences in the decline in stroke mortality in the past, and in the predicted decline in the future. White males have had the largest decline of stroke mortality and black males the smallest. Generally, stroke mortality appears to still be declining (slowly) for African Americans, but not for whites. Racial and gender differences in stroke mortality are predicted to persist when stroke mortality rates plateau. Discussion: The analysis suggests that the deep south (AL and MS) will fall from the highest stroke mortality rates in the nation and be replaced by other regions (notably OR, WA and AR). New York City and Southern FL had very low stroke mortality rates in 1968, have experienced large declines and also appear to be experiencing continued substantial declines — resulting in even greater geographic heterogeneity of stroke mortality rates. The reasons for these differences between race, sex and region in the pattern of the decline in stroke mortality are not understood.