Biological inequity

Biological inequity posits that health inequity in urban populations is a result of structurally racist processes executed through the built environment. Specifically, particular social groups are disproportionately exposed to physical and psychosocial stressors in the urban environment. For example, studies show Black, Asian, and Minority Ethnic (BAME) groups inhabit more deprived^[8] and environmentally polluted neighbourhoods.^[9] Through this, these groups experience prolonged exposure to physical (e.g., air pollution^[10]) and psychosocial (e.g., discrimination^[11]) stressors resulting in chronic stress.^[11] Chronic stress increases the individuals ‘allostatic load’ level – which refers to the wear and tear of stress-related biological systems e.g., neuroendocrine, metabolic, immune systems. In turn, these stress-related biological differences increase the risk of disease and poorer health outcomes.^[12][13]

Measures have been developed to quantify biological inequity by combining physical (e.g., air pollution, noise pollution, light pollution) and psychosocial factors (e.g., deprivation) that define the phenomena, such as the ‘Biological Inequity Index.^[14]

As a phenomenon, biological inequity is situated at the intersection between poverty, structural racism, and place. As such, biological inequity as expressed through allostatic load is correlated with factors such as socioeconomic status,^[15] ethnic and racial grouping,^[16] and urban factors e.g., green space,^[17] and housing quality.^[18][19]

Biological inequity increases the risk of disease and poor health outcomes for a social group through;

1. disproportionate exposure to the cause(s) of the disease brought about by direct exposure to physical and/or psychosocial stressors, or
2. greater adverse effects of the cause(s) of a disease brought about from accumulated stress-related biological differences, i.e., higher levels of allostatic load.^[1][20]

Obesity has been linked to biological inequity factors such as air pollution^[21][22] and psychosocial stress.^[23] Similar findings have shown diabetes to be associated with physical^[24] and psychosocial^[25][26] stressors.

Mental health conditions such as depression, anxiety have been linked to biological inequity factors such as air pollution,^[27][28] noise pollution^[29][30] and area deprivation^[31][32]

Measures of Biological inequity such as psychosocial stress and environmental stress have been shown to correlate with COVID-19 mortality rates, suggesting possible increased exposure to COVID-19 or increased vulnerability to the virus.^[1]

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