Lower stroke mortality among Hispanics: an exploration of potential methodological confounders

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.

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).

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.