Lower stroke mortality among hispanics: An exploration of potential methodological confounders

OBJECTIVES: Stroke mortality rates are reported to be lower for Hispanics than non-Hispanic Whites. We investigate the degree to which this lower reported mortality is explained by inaccuracies introduced through omission of nativity, imprecise measurement of cause of death, and under-ascertainment of Hispanic ethnicity on death certificates. We used national vital registration data for the years 1989-1991 and 1999-2002, including foreign-and US-born Hispanics and non-Hispanic Whites. Hispanic deaths were adjusted for misclassification of ethnicity on the death certificate. Denominators for the rates were derived from census estimates. RESULTS: Adjustment for nativity and death certificate misclassification removes the stroke mortality advantage for US-born Hispanic men, but not women. After adjustment, US-born Hispanic men and women have higher rates of mortality from subarachnoid hemorrhage than non-Hispanic Whites (RR: 1.23 and 1.23, respectively), but lower rates of mortality from Ischemic (RR: 0.76 and 0.73, respectively) and chronic effects of stroke (RR: 0.87 and 0.73, respectively). CONCLUSIONS: When adjusted for misclassification the lower stroke mortality remains for Hispanic men and women at older ages. Part of the previously reported advantage is a combination of imprecise measurement and data quality.