Ō Tātou Tinana me te Hinengaro: A Study of Microaggressions, Discrimination, and Cardiovascular Regulation in Māori

Abstract

Hypertension is one of the largest preventable diseases worldwide, and affects social groups at varying rates. In Aotearoa-New Zealand, a large hypertension disparity exists between Māori and Pākehā. Previous research has indicated that racial discrimination may, at least in part, account for such a disparity. As overt racial discrimination is being replaced by more subtle forms, it is also possible that microaggressions are important to this relationship. The key objective of this study was to evaluate how low or high experiences of microaggressions influence cardiovascular regulation in Māori following exposure to an ambiguous or racist discriminatory scenario. In order to determine ones experience of microaggressions, potential participants were pre-screened with the Racial and Ethnic Microaggressions Scale (Nadal, 2012). The top and bottom tertiles of those who completed the scale were invited to participate in the experimental protocol. The experiment was randomised and consisted of a baseline measurement, neutral reading, speech, and anger recall tasks, interspersed with recovery periods. Participants were exposed to either the ambiguous or racist discriminatory shopping scenario prior to the speech task. Throughout the protocol, systolic and diastolic blood pressure, mean arterial pressure, cardiac output, heart rate, stroke volume, and total peripheral resistance were recorded. A total of 43 participants (n=13 males) completed the protocol and were included in the final analysis. In the racist discriminatory condition, Māori who were less sensitive to microaggressions were found to have a blunted cardiovascular response to the speech task, and a normal resistance mediated response to the anger recall task. Conversely, Māori more sensitive to microaggressions exhibited an enhanced cardiac output response to both tasks when in the same condition, indicating prolonged activation of centrally mediated blood pressure mechanisms. The multivariate analysis revealed no significant physiological findings for the ambiguous condition, though the reactivity analysis revealed enhanced blood pressure responses to this condition. Overall, this study indicates that sensitivity to microaggressions and exposure to discrimination has an important influence on cardiovascular regulation in Māori. It also emphasises that discrimination may contribute to the development and maintenance of hypertension in a particular subset of the Māori population.