Background Blacks have higher risk for stroke than whites. However, combining foreign-born and US-born blacks could mask important health differences. We examined the relationship between nativity and stroke risk in US adults.

Methods Data were obtained from the National Health Interview Survey, 2006–2014. Study population (n=189, 409) included non-Hispanic whites and non-Hispanic blacks born in the Caribbean, and non-Hispanic blacks born in Africa. Logistic regression models were used to assess the association between stroke and race/nativity, adjusting for covariates such as insurance status, hypertension, age and duration of US residence.

Results Foreign-born blacks had similar odds of stroke (95% CI 0.58 to 1.60 for non-Hispanic blacks from the Caribbean, and 95% CI 0.17 to 1.10 for blacks from Africa), while US-born blacks had increased odds of stroke (95% CI 1.22 to 1.46) compared with non-Hispanic whites. When compared with US-born blacks, both non-Hispanic blacks from the Caribbean and Africa showed reduced odds of stroke: 95% CI 0.50 to 0.94 and 95% CI 0.21 to 0.75, respectively. After adding a race/nativity × age interaction term to the model however, compared with non-Hispanic whites, blacks from Africa aged <65 years had lower odds of stroke (95% CI 0.13 to 0.72) while blacks from the Caribbean had similar odds of stroke at all ages.

Conclusions Homogenising ‘Blacks’ may mask important differences based on nativity. Public health prevention efforts should consider the heightened risk of stroke among younger US-born blacks and focus on primary prevention for immigrant blacks. Also, national surveys should incorporate more ethnicity-related variables.