Past-Year Racial Discrimination and Allostatic Load Among Indigenous Adults in Canada: The Role of Cultural Continuity

Abstract

Objective: This study aimed to examine the association between racial discrimination and allostatic load (AL) and whether this association was moderated by cultural continuity among Indigenous adults.

Methods: Data were collected from Indigenous adults attending university in a small city in western Canada between 2015 and 2017 (mean age = 27.8 years). The Experience of Discrimination Situation Score and the Vancouver Index Enculturation Subscale were used to assess racial discrimination and cultural continuity, respectively. AL was measured as a composite of seven biomarkers assessing neuroendocrine, cardiovascular, metabolic, and immune system function. Bias-corrected and accelerated bootstrapped linear regression models were used to examine associations adjusting for confounders (n = 104; 72.5% women).

Results: Across the full sample, racial discrimination was associated with a linear, dose-response increase in AL score after adjustment for confounders. Among adults with low cultural continuity, past-year discrimination was associated with increased AL and explained 22% (adjusted R) of the variance in AL score. Taken together, the full model including age, sex, and income explained 38% of the variance in AL score in this subgroup. Among adults with high cultural continuity, racial discrimination was not associated with AL, whereas age remained significant and explained 13% of the variance in AL score.

Conclusions: Past-year racial discrimination was associated with early and more pronounced wear and tear on stress response systems among Indigenous adults relative to peers. Indigenous cultural continuity served as an important buffer that promoted biological resilience against the adverse effects of racial discrimination on physiologic regulation among Indigenous adults.

FIGURE 1

Linear and LOWESS associations between the number of situations in which discrimination was experienced in the past year and AL score (n = 104). LOWESS = locally weighted scatterplot smoother; AL = allostatic load.

FIGURE 2

Linear and LOWESS associations between the number of situations in which discrimination was experienced in the past year and AL score, stratified by Indigenous cultural continuity (n = 104). LOWESS = locally weighted scatterplot smoother; AL = allostatic load. Color image is available only in the online version (www.psychosomaticmedicine.org).