The Influence of Discrimination and Identity on Blood Pressure in Aotearoa/New Zealand: A physical and mental challenge in a rural Northland Māori Sample

Abstract

Hypertension is a silent killer that is associated with high morbidity and mortality rates throughout the modern world. In Aotearoa/New Zealand a hypertension disparity between Māori and Pākehā exists. The mechanism of this hypertension disparity is not clearly understood, however, there is reason to believe psychosocial determinants play a pivotal role. The present study aimed to investigate if any relationship exists between the psychosocial factors, perceived discrimination and ethnic identity, on the blood pressure response of rural Māori to an evocative mental stressor. The study assessed the effect of perceived discrimination and ethnic identity on cardiovascular function under conditions of physical and psychological stress with 29 rural Northland Māori participants. In order to assess psychological stress response, the participants conducted an adapted social stress test. Physical stress was assessed using a standard orthostatic challenge. Results indicated that dichotomised groups of perceived discrimination, social exclusion and authenticity beliefs exhibited differing cardiovascular responses to the psychological stress task. Dichotomised high groups exhibited lower cardiovascular responses than low groups. This suggests, when exposed to psychological stress, rural Northland Māori who self-report being high on these psychosocial factors exhibit blunted cardiovascular activity, and those that self-reported low exhibited situationally appropriate responding. This blunted responding is interpreted as arising from chronic stress and allostatic load that develops as a consequence to psychosocial stressors. Taken together, blunted responding to psychological stressors could be detrimental to health via physiological and health behavioural pathways. The findings of this study, suggest a new approach to understanding health disparities and clinical assessment of cardiovascular activity. Future research may well like to consider whether the identified blunted responding is a Maori wide phenomenon, and if these psychosocial factors are indeed involved in the well documented hypertension disparities between Māori and Pākehā.