Race, racism and diabetic kidney disease

Disparities in health burdens were explored at the American Diabetes Association’s 83rd Scientific Sessions. Lisa Buckingham reports. 

Individuals from underrepresented groups in the US suffer from chronic kidney disease (CKD) at a rate that is higher than White individuals, said Titilayo Ilori, Assistant Professor at Boston University School of Medicine. Similarly, the burden extends to other under-represented groups living across the world. Racism is a factor that amplifies the effects of diabetes and kidney disease, she said, especially in the US, and it should be a focus for all of us as clinicians, researchers and epidemiologists.

Professor Ilori started with a global view with the first example being the Glasgow effect – a tale of two areas in Glasgow, UK, called Calton and Lenzie. There is a 28-year life expectancy gap between the two areas and one in four men in Calton will die before they’re 64. Income levels have been associated with poor health and a shorter lifespan but epidemiologists believe that poverty alone does not appear to account for this disparity. The Economist puts it like this: ‘It is as if a malign vapour rises from the Clyde at night and settles in the lungs of sleeping Glaswegians’. 

In the US, if you catch the Metro from the southeast of downtown Washington to Montgomery County in Maryland, life expectancy rises about a year and half for every mile travelled. A 24-year gap exists between both ends of the line. In these two examples is a vivid and palpable social gradient in health and understanding the pervasive factors is crucial for us to improve health. 

Why do we treat people and send them back to the conditions that make them sick? Professor Ilori used the example of a patient with multiple social and emotional problems and the clinician thinking, ‘is this a red or blue pill problem?’. Is it beyond us as clinicians to help solve these problems, she asked. 

Disparities in prevalence 

Prevalence of CKD is three times higher in Black Americans than White Americans. The lifetime risk of end-stage kidney disease (ESKD) is four times higher in Black Americans than White Americans. It’s also 1.2-1.3 times higher in American Indians and Hispanic Americans. The median age of onset of kidney disease is almost 10 years earlier in Black Americans versus Non-Hispanic White Americans, with Black Americans presenting as early as 30 years old. 

With regard to disparities in the risk factors for CKD, the risk of having a diabetes diagnosis is 77% higher among African Americans, 66% higher among Latino/Hispanic Americans and 18% higher among Asian Americans. Obesity prevalence is 1.5 times higher in Black and Hispanic Americans compared with White Americans and CKD attributable to hypertension is 12 times higher in Black Americans compare with Non-Hispanic White Americans. 

Professor Ilori highlighted a study that looked at the proportional mortality from kidney disease in the US (the proportional mortality refers to the percentage of deaths due to kidney disease over the number of deaths from all causes). The highest percentage is found in Filipino Americans, even higher than Non-Hispanic Black Americans, the second highest group. 

We do know that genetic factors play a significant role, she said. Not specifically with diabetic kidney disease but the two risk variants of APOL1: G1 and G2, which were discovered in 2010, explain 70% of the excess risk of CKD in African Americans. However, not all African Americans with APOL1 high-risk status develop CKD, suggesting that there is a gene-to-gene or gene-to-environment interaction acting on the individuals with a background of high risk. 

Social determinants of health

Much research is focusing on gene-to-environment but what is the impact of the social determinants of health (SDOH)? The World Health Organization (WHO) defines these as the conditions in which people live, grow, work and age, and these circumstances tend to distribute money and power in different ratios at the global, national and local levels. They create a social stratification that is responsible for a lot of health inequities but the interesting thing about SDOH is that they are all amplified by structural racism. In fact, much epidemiological research has shown that social and environmental influences are highly significant, contributing to between 45% and 60% of the variation in health status. 

Next, she looked at race versus genetics versus ancestry.

• Race is a concept defined by society, not by genes. It’s true that people around the world differ genetically due to their ancestry and that people’s racial identity may be statistically correlated with their ancestry 
• It is shaped by geographical, cultural, sociopolitical forces so the definition changes over time and geography 
• There is no national consensus for definitions of race and ethnicity
• Self-reported race and ethnicity can mean something different depending on location and cultural norms; a person’s racial identification is therefore highly subjective 
• Race does not mean ancestry – ‘biological races are not a current scientific concept and often reinforce historical biases’ (The Atlantic, 2018)
• Genetic ancestry is the genetic origin of one’s population and ancestry is a predictor of genetic variants of disease within a population or an individual

With regard to racism and health, she highlighted a 2019 paper stating that:

• Racism includes a complex array of social structures, interpersonal interactions and beliefs by which the grouping peer categorises people into socially constructed ‘races’ 
• It creates a racial hierarchy in which individuals from under-represented groups are disempowered, devalued and denied access to resources 
• Racism is often systemic or structural   

She showed the ‘house that racism built’, adapted from Dr Williams of the Harvard School of Public Health. Racism is a societal system that includes political, legal, economic, religious, cultural and historical forces but people often tie racism to the actions of an individual perpetrator such as a healthcare professional who’s denying equitable care to an under-represented group. This narrow perspective ignores structural racism in healthcare, which is structured to be of advantage to some populations and disadvantage many of the under-represented groups.

Discrimination can get under your skin, said Professor Ilori, and it’s known as the allostatic load – the cumulative impact of physical wear and tear related to maladaptive stress patterns that predispose individuals to disease. How? You have the early life adversity and stress exposure that lead to behavioural, psychological and inflammatory responses to these stressors that may affect endothelial dysfunction and atherosclerosis, leading to diseases such as kidney disease as well as diabetes. 

When you look at structural racism affecting kidney pathophysiology, there are two possible pathways – it could act through SDOH leading to food insecurity, inappropriate housing, exposure to pollutants, access to health insurance etc and lifestyle implications such as high ingestion of cooked meat, hyperglycaemia and high blood pressure, but there could also be a general biological impact whereby structural racism increases allostatic load, alters gene expression, increases nervous system activity and leads to altered metabolism of insulin and other hormones. Downstream, you then get hyperfiltration, estimated glomerular filtration rate (eGFR) decline and renin-angiotensin-aldosterone system (RAAS) activation and inflammation. 

With regard to the impact of segregation, Professor Ilori highlighted a study showing that Black patients on dialysis with ESKD who lived in counties where Black and White residents live apart from each other experience greater mortality compared with Black patients who live in counties with less segregation. 

She then covered disempowerment – a downstream effect of structural racism. Tackling it is crucial for improving health and health equity because if a person is not in control of their life, decisions to improve health will be difficult. Furthermore, disempowering people and depriving them of control can lead to stress and a greater risk of physical and mental illness. 

So what do we tell our patients, she asked. To just keep swimming? Some of the interventions to address structural racism and SDOH in diabetic kidney disease were recently addressed at a workshop day at the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). Here are some of the takeaways: 

• We need to delineate institutional racism from structural and accelerate research on both 
• There needs to be proper interpretation of race variables in research, equations and algorithms. 
• There needs to be effective policy and authentic antiracist research from within the affected community and cultivated by the community 
• We need to develop frameworks that explicitly outline the link between structural racism and CKD, especially in individuals with diabetes 
  

For research into structural racism and DKD, we need to:

• Allow for a more nuanced approach to understanding disparities at subgroup levels that may be hidden – for example, ‘Asian’ could be Japanese, Indian, Korean, Cambodian, Filipino or Chinese
• Develop new measurement approaches to capture the multifaceted nature of structural racism as a systemic sum of exposures and not just a single variable

As scientists and physicians, she said, we should constantly and rigorously ask ‘how might racism be operating here?’ and focus on what discriminatory policies and practices might be identified that produce and/or sustain racial inequity. 

To promote structural interventions, we need to:

– Promote interventions that can address major structures or drivers of health such as economic status, educational attainment, built environment, community support and access to care

– Look at how multi-level interventions are going to be needed as we map out the frameworks that link structural racism to DKD. We need to look for interventions that will address structural racism at the patient, provider and system level, interventions that will address the multiple levels of structural drivers eg food security and advance health equity through new healthcare models 

– Foster research by and for the community and develop community partnerships. Having non-academic stakeholders as partners is crucial to optimising antiracial intervention. 

The question remains, said Professor Ilori, why have we continually failed to achieve health equity despite improvements in certain areas of civil rights? She likened it to the pattern on the sides of a soccer ball with each side of it as a societal institution like a carbon atom that perpetrates institutional racism – structural racism derives its strength from the interconnections between all of these carbon atoms. If you just focus on one aspect of it, you just create a pit in the ball, but it retains its structure. 

In summary:

• Disparities exist in diabetes and kidney disease
• Structural racism is a major factor in these disparities 
• Structural racism amplifies SDOH
• We need to work on frameworks that explicitly outline the link between structural racism and CKD
• We need effective policy and authentic antiracist research from within the affected community and subsequently cultivated by it 

To learn more about diabetic kidney disease, enrol on the EASD e-Learning course ‘Diabetes and the kidney’.

Any opinions expressed in this article are the responsibility of the EASD e-Learning Programme Director, Dr Eleanor D Kennedy.