Why are those of African descent more prone to diabetes, hypertension, sickle cell anemia, and COVID-19?
By Cebastian Blot, JSTEP Global High School Fellow (Cosby High School — Governor’s Health Science Academy ‘24)
In Spring 2023, Columbia JSTEP hosted 150 high school students from 35+ countries to participate in a 10-week long virtual program to educate students on the intersections of science, technology, ethics, and policy. In addition, we provided support as they pursued a written or creative project based on research they did at this intersection over the course of the program. Articles where the author is denoted as a “JSTEP Global High School Fellow” indicates that the writer completed our program.
Introduction/Abstraction:
In 1619, the privateer, The White Lion, set sail from Africa to the Virginia Company’s Jamestown with 20 Africans enslaved — unintentionally setting the immoral precedent for decades to come. For more than 200 years, the United States of America had continuously treated the growing population of slaves with beatings, sexual abuse, denial of education, and many other racist practices. To justify this stain in their history, the United States used the term scientific racism to enforce the African Slave Trade [Triangular Trading System]. Many scientists and doctors argued that the African diaspora was distinctly fit for enslavement because of their physical strength and “simple minds”. Although centuries down the line slavery was abolished with the ratification of the Thirteenth Amendment, the medical and societal perspective of the United States is still thriving on the foundation of one racial concept: Social Darwinism.
While it is true that the bondage of slavery ended in the United States with the Thirteenth Amendment, the concept of racism has only transformed into intergenerational ripples in the African American community. More specifically, according to the World Health Organization’s report Closing the Gap in a Generation: Health Equity through Action on the Social Determinants of Health, “unequal living conditions are the consequences of deeper structural conditions that together fashion the way society is organized–poor social policies and programs, unfair economic arrangements, and bad politics.” These detrimental factors, when coupled with the faced transgenerational racism, disproportionately affect the African American community. More specifically, these observations can be seen in Black Americans’ overarching susceptibility to diabetes, hypertension, sickle cell disease & COVID-19.
Genetic/Systemic causes for the Prevalence of Diabetes in those of African Descent:
As noted by M.C. Marshall Jr.,
African Americans have a high risk for type 2 diabetes. Genetic traits, the prevalence of obesity, and insulin resistance all contribute to the risk of diabetes in the African American community. [More specifically], African Americans have a high rate of diabetic complications because of poor glycaemic control and racial disparities in health care in the United States of America.
While the reasons behind these findings remain ambiguous, one genetic hypothesis that can explain the prevalence of diabetes in the African American community is the thrifty gene theory. In this hypothesis, populations subject to continuous intervals of deprivation developed an advantageous survival trait: “a genetic predilection for efficient storage of fat.” (Marshall). This fat would allow said populations to sustain themselves until food became readily available again. Therefore, it must be stated that the same genetic trait leading to efficient fat storage will eventually cause momentous insulin resistance.
While not everyone with diabetes is insulin resistant and not everyone with insulin resistance will develop diabetes, insulin resistance is said to be a precursor to glucose intolerance, hyperglycemia, and overt diabetes. Insulin resistance is defined as the inability of cells in one’s muscles, liver, and/or fat to absorb glucose from our blood. The human body is a well-controlled system that makes and uses insulin efficiently. Insulin resistance disrupts this mechanism, which can consequently cause higher blood sugar levels and type 2 diabetes. For many African Americans, the rate of insulin resistance is seen at a much higher rate than their white counterparts, as stated by Goran MI. An explanation for this can be inadequate physical activity, smoking, and even some medications but the cause or causes remain unknown. While the causes of this disparity in insulin resistance remain in question, one possible cause from Tanya Hyatt is simply inflammation, commonly associated with type 2 diabetes and cardiovascular disease. Moreover, this inflammation is said to be caused by higher concentrations of C-reactive protein (CRP) in African Americans. In high concentration, CRP increases the likelihood of developing cardiovascular events both in diabetic and nondiabetic populations; therefore, in apparently healthy subjects, increased levels of CRP predict the risk of developing type 2 diabetes. (Mugabo)
Besides insulin resistance, another significant cause for the prevalence of diabetes among African Americans is the lack of adequate control and its systemic implications. Across four different studies done by the NIH, African American and Hispanic diabetic patients are controlled more poorly than their white counterparts, highlighting the racial differences in glycemic control. More specifically, Michele Heisler’s observational study of 801 white and 115 black patients who completed the Diabetes Quality Improvement Project survey found that Blacks were less likely than Whites to have low-density lipoprotein (LDL) checked in the past 2 years. “Even after adjusting for patients’ age, education, income, insulin use, diabetes self-management, duration, severity, comorbidities, and health services utilization, racial disparities in receipt of an LDL test and eye examination persisted.” (Heisler). Overall, insulin resistance is accompanied by the overproduction of low-density lipoproteins which then will have detrimental implications on cholesterol levels.
While healthcare disparities due to race are an essential implication discussed later in this paper, its play in the increased morbidity in African Americans with diabetes must be discussed. According to the Institute of Medicine (US) Committee on Understanding and Eliminating Racial and Ethnic Disparities in Health Care, ethnic and racial minorities in the United States are found to receive a lower quality of health, despite their socioeconomic background, geographic area of residence, or comorbid conditions. In a study done by M. H. Chin, “African American diabetic patients were less likely to have glycosylated hemoglobin measurements, lipid testing, or ophthalmological visits than white diabetic patients.” (Marshall). Although some might state that this discrepancy is due to access to healthcare, SES, disability status, and socioeconomic status, all of the subjects in Chin’s study were either 65 or older and were enrolled in Medicare, a United States federal health insurance.
Sadly, this discrepancy in the quality of care can even be seen in African American veterans. In a similar study done by Bessie Young on the effects of ethnicity and nephropathy on lower-extremity amputation in diabetic veterans, African Americans and other ethnic minorities were seen to have an increased risk of lower-extremity amputation compared with their white counterparts.
Although the treatment plan and management of diabetes remain specific to each patient, lifestyle changes in diet or exercise are recommended for everyone. More specifically, according to a study done by the Diabetes Prevention Program, lifestyle intervention reduced the incidence of diabetes by 58%, while metformin, a drug that lowers blood sugar levels, only reduced diabetes by 31%, as seen in Figure 1.
Evidently, it must be stated that when lifestyle changes are ineffective and fall short, pharmacological intervention becomes necessary. A common treatment plan for diabetic patients is insulin therapy, which improves glycemic control in type 2 diabetes, especially for overweight patients. Another is continuous subcutaneous insulin infusion (CSII), which proves particularly useful for those whose lifestyles preclude regimented schedules. As for pharmaceutical intervention, there are 10 oral antidiabetic drugs listed in the Physicians’ Desk Reference (PDR): the sulfonylureas — glyburide (glibenclamide), glipizide, glimepiride, metformin, thiazolidinediones, rosiglitazone, repaglinide, nateglinide, α-glucosidase inhibitors, and miglitol.
Despite all these aggressive treatments for diabetic patients, a vital issue in the management of African American diabetic patients still remains the lack of appropriate intensification of treatment to achieve adequate glycemic control. Furthermore, multiple interconnected factors can be credited for this discrepancy, such as the lack of self-monitoring, inconsistent treatments, and other sociocultural factors; “Physicians’ perceptions and/or bias in treating African American patients, communication barriers, as well as time constraints in a busy clinical practice” (Marshall) all can be cited for this prevalent problem.
Genetic causes for the Prevalence of Hypertension in those of African Descent:
Historically, African Americans have been disproportionately at higher risks for chronic diseases such as hypertension, diabetes, and cancer — underlying conditions that may make viruses more lethal. Through a pandemic, these discrepancies and disparities are brought so vividly into focus.
As stated by the director of the National Institute of Allergy and Infectious Diseases, Doctor Anthony Fauci, African Americans getting infected more often is not the true issue at hand, it’s that when they do get infected, their underlying medical conditions “wind them up in the ICU and ultimately give them a higher death rate.” (Fauci). One of these underlying medical conditions that has remained rampant and consistent in African Americans is hypertension (Figure 2).
According to a report by the American Heart Association, it has been proven that African Americans have a higher prevalence of hypertension than their white counterparts, a pivotal precursor to the higher influx of cardiovascular disease in Black Americans. While the list of these causes still remains extensive, biological differences in the mechanisms of blood pressure control and the environmental/behavioral characteristics of African Americans can be said to primarily contribute. According to the Slavery Hypertension Hypothesis, the high blood pressures measured in African Americans are caused by one or more of these conditions: first, salt deficiency in the parts of Africa that supplied slaves for the Americas. Second, the trauma of the slave trade itself, and third, the conditions of slavery in the United States. This would induce a high rate of hypertension, as descendants of slaves and slaves themselves instantaneously grew to eat more sodium-concentrated American cuisine versus their normal African foods. However, “this hypothesis [still remains] hard to confirm or refute” (Fuchs).
More genetically speaking, Norman Kaplan’s book Clinical Hypertension and Kao’s MYH9 research lists 18 genotypes and intermediate phenotypes implicated with the increase of blood pressure (BP) in African Americans, along with an association between the genetic traits causing hypertension and renal outcomes. Of these traits, there is one association between a genetic variation of the MYH9 region on chromosome 22 “with focal segmental glomerulosclerosis, a condition previously attributed to “hypertensive nephrosclerosis” (Fuchs). This means that these genetic defects account for the higher propensity of African American to “develop end-stage renal disease, which may then induce hypertension, rather than hypertension being responsible for the renal damage.” (Fuchs) This association was also found more frequently in black patients with end-stage renal disease than their white counterparts, with the MYH9 genotype found in nearly 74% of Black people but only 4% of White people. Similarly, in a study on missense mutations in the APOL1 gene and end-stage kidney disease, it was found that similar genetic defects contributed to the high prevalence of end-stage renal failure in African Americans, which may later induce hypertension.
Ultimately, while these genetic defects in the larger majority of black Americans still remain a significant factor, differences in socioeconomic status, dietary habits, stress, and health behaviors all can further contribute to the high prevalence of hypertension.
Genetic causes for the Prevalence of Sickle Cell Anemia in those of African Descent:
Sickle cell anemia is caused by a point mutation on the B-hemoglobin gene (HBB glu6val) that induces faulty hemoglobin proteins (HbS). This detrimentally affects the shape of red blood cells. More specifically, red blood cells contort into a sickle shape; dying prematurely, leaving a shortage of healthy red blood cells and oxygen (Figure 3). Patients with sickle cell disease inherit two faulty hemoglobin genes called hemoglobin S — one from each parent. With these two genes, they are considered homozygous for this mutation and suffer from acute vaso-occlusive events, hemolytic anemia, and a lifespan reduction. Globally, this mutation of the HbS is seen at a high frequency through “Africa, the Middle East, and the Indian subcontinent” (Solovieff).
The inheritance pattern from the Centers for Disease Control can be seen in the scenario and image below:
- If both parents have [the Sickle Cell Trait], there is a 50% (or 1 in 2) chance that any child of theirs also will have this trait, if the child inherits the sickle cell gene from one of the parents. Such children will not have symptoms of Sickle Cell Disease, but they can pass [the Sickle Cell Trait] on to their children.
- If both parents have [the Sickle Cell Trait], there is a 25% (or 1 in 4) chance that any child of theirs will have Sickle Cell Disease. There is the same 25% (or 1 in 4) chance that the child will not have the disease or the trait itself.
As stated by the National Heart, Lung, and Blood Institute, in the United States of America, most people who have sickle cell disease are African American. More specifically, about 1 in every 13 Black babies are born with a sickle cell trait. While 1 in every 365 is born with the disease itself; a potential flaw in Darwin’s claim is that harmful traits disappear in the gene pool through natural selection. Furthermore, it was found that this prevalence is a direct mechanism to help those of African descent combat malaria. In a study done by Tony Allison, it was found that places with a higher prevalence of sickle cell anemia also had high malaria rates. More specifically, in this study, each patient’s blood sample was taken and the malaria parasite load was very low for the carrying of the sickle cell character as if they were partially protected from malaria. However, it must be re-stated that the evolutionary trade-off of malaria comes at the cost of the frequency of sickle cell disease in a population.
Ultimately, while this sickle cell mutation is not the best solution to combat malaria, it is the most available. A simple substitution mutation, where one nucleotide in hemoglobin is exchanged for another: Adenine (A) → Thymine (T). For most African Americans, this mutation would present as a detrimental mutation, but for those living in malarial areas, it provides an advantage against the malaria parasite.
Genetic/System causes for the High Prevalence of COVID-19 in those of African Descent:
Since January 20, 2020, the COVID-19 pandemic has infected more than 7.7 million people across the entire United States of America, along with its four territories. However, these staggering statistics only depict half of the outcome; by looking at different social identities (class, age, race, and medical background) it is shown that minorities are disproportionately affected by this pandemic (Figure 5). For instance, it was found that in Kansas, out of 94,780 tests, only 4,854 were from African Americans and 50,070 were from white Americans; however, black Americans make up almost 33% of Kansas COVID-19 deaths. This discrepancy can be accredited to historical roots. More specifically, legal segregation, discrimination in the labor market, and redlining, the practice of denying home loans to those living in predominantly African-American neighborhoods. When piled together, these factors can cascade into a persistent racial wealth gap, with African Americans unable to move into neighborhoods that their White counterparts live in to better avoid exposure to COVID-19.
Prior to the Affordable Care Act of 2010, around 20% of African Americans remained uninsured. Through this act, the rate of the uninsured decreased from 18.9% to 11.7%. (Reyes). However, despite reformative legislation, the decrease in the uninsured still had African Americans being the most uninsured demographic in America: less likely to have medical visits, procedures, and even medications because of cost.
As stated by the Mayo Clinic, one major cause of African Americans and Hispanic people being more than two times more likely to need to stay in the hospital due to COVID-19 is because of underlying health conditions. More specifically, because of the high prevalence of hypertension, diabetes, and heart disease in African Americans, those with COVID-19 are dealing with multiple symptoms and barriers to their health. Contracting COVID-19 whilst having an underlying health condition will trigger a cascade of effects that make African Americans rehospitalized for disproportionate amounts of time, as stated by the Centers for Disease Control.
Similarly, African Americans see a high prevalence of COVID-19 because of their direct exposure to the pandemic. Following the stay-at-home mandates from the federal and state level governments, the social network of America saw a halt. However, for many individuals that are considered crucial workforce occupants by the U.S. Department of Homeland Security, the ability to simply stop working or work remotely is not an option. More specifically, for healthcare providers, cashiers, sanitation workers, farmers, and public transport employees, jobs often filled by African Americans, direct contact with those with COVID-19 and other airborne viruses is omnipresent. Moreover, the United State Bureau of Labor Statistics found that around 30% of employed African-Americans work in the education and healthcare industry and 10% in retail (Figure 6). As stated by the Mayo Clinic, “Black people make up about 36% of workers in nursing”.
Moreover, while it may seem common for workers to drive themselves to work daily, for many African Americans this is simply not possible. From a report done by Pew Research Center, it was found that 34% of African Americans use public transit regularly, compared to only 14% of white Americans. Through this, more than a third of African Americans are forced to use public transit to further expose themselves to areas with higher rates of COVID-19, while their white counterparts tend to either work remotely or simply use their own vehicle, as stated by the United States Bureau of Labor Statistics.
Additionally, this trend still runs through the housing crisis for African Americans, as a result of redlining, gentrification, and other racist tactics used throughout history to widen their economic gap. As seen in the January 2020 United States of America Census, it was found that only 44% of African Americans own their own home compared to 74% of their white counterparts owning theirs. The other 56% of African Americans result in living in homes with several family members of various ages, crowded apartment complexes or often both. To explain this direct detriment, Martina Anto-Ocrah of the University of Rochester Medical Center states a simple question: “Can you possibly take an elevator [at these apartment complexes] alone? No.”
The Underlying Racism and Discrimination in the Healthcare Industry
Throughout this entire analysis of the different disparities faced by those of African Descent, there has been one clear, underlying factor, racism and discrimination. For years, African Americans have faced seemingly insurmountable obstacles in their pursuit of political, social, economic, and now medical equity and equality. And for that same amount of time, education officials, policymakers, elected officials, and the very heart of America have been reluctant to identify racism as the root cause of these health inequities. An example of this can be seen in the Tuskegee Experiments of 1932–1972, in which hundreds of black men with syphilis were denied treatment for decades.
Through the U.S Public Health Service (USPHS) Syphilis Study at Tuskegee, 600 African American men in Macon County, Alabama were enrolled in order to study the full progression of Syphilis. While 399 men were infected with syphilis and the other 201 were free of the disease, doctors told all of the participants that they were being treated for bad blood. For 15 years into the study, the doctors proceeded to only give the men aspirin and other placebos, despite the discovery of penicillin as a direct medication for syphilis. “PHS researchers convinced local physicians in Macon County not to treat the participants, and instead research was done at the Tuskegee Institute.” (Nix). In order to solely track the progression of syphilis in each participant, U.S Public Health Service researchers provided no care for the men as they died, became blind, declared clinically insane, or experienced other symptoms of untreated syphilis.
Despite the repudiation of this disparaging and racist experiment, there is transgenerational racism in the healthcare field still felt today. For example, it can be currently seen by the Center for Disease Control that Black women are three times more likely to die from a pregnancy-related cause than White women. Black men have been found to have the lowest life expectancy of all major ethnic-sex populations in the USA by Elizabeth B Pathak for the NIH. While the list of healthcare disparities in the African American community continues, the game of jeopardy of their lives shall not. As stated by Martin Luther King Jr in 1966, “Of all the forms of inequality, injustice in health is the most shocking and inhumane.” More than half a century later, African American still suffer from these same injustices that fall on the basis of income and health disparities.
Conclusion
To combat these high prevalences and disparities felt by those of African descent, we must begin to ask ourselves how. How can governments and elected officials avoid further marginalizing or stigmatizing this vulnerable community? How can we as a society effectively treat this population, instead of sending them back to the conditions that made them sick? How can approaches be taken to ensure human rights and health justice for all in order to achieve a better society onward? These questions require targeted, specific responses; not just in treatment, but also in preventative care.
We must reference the constitution’s “inalienable rights” and begin to treat the right to life and liberty with not only care but with human dignity. In order to provide such respective care, we must first acknowledge that America does not simply have a healthcare system, but rather a Sickness Care system. A system that waits until marginalized people get sick, and points fingers on who is to pay for the treatment and how they are going to be treated. Thus, we must first acknowledge these inalienable rights, and create reformative legislation that recognizes the inherent dignity of the people, by the people, and for the people.
Similarly, we must analyze the underlying obstacles that came as a result of centuries of racism and discrimination and begin to address their detrimental effects. More specifically, elected officials must begin to design legislation that targets universal healthcare for all because who you are and where you reside should never determine whether you live or die.
Finally, we must collect meaningful, systemic, and disaggregated data by race, sex, age, and class, not only to address the implications of diabetes, hypertension, and COVID-19 but to design policies that focus on equity rather than capital gain. When Martin Luther King Jr. described his hope for living in a colorblind world, he did not mean that we should ignore race entirely. Being “colorblind” ignores a significant part of a patient’s identity and dismisses the real injustices that many face as a result of race. We must see color in order to work together for equity and equality for all.
