Race and health
Encyclopedia
Race and health research, often done in the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

, has found both current and historical racial differences in the frequency, treatments, and availability of treatments for several diseases. This can add up to significant group differences in variables such as life expectancy
Life expectancy
Life expectancy is the expected number of years of life remaining at a given age. It is denoted by ex, which means the average number of subsequent years of life for someone now aged x, according to a particular mortality experience...

. Many explanations for such differences have been argued, including socioeconomic factors (e.g., education, employment, and income), lifestyle behaviors (e.g., physical activity and alcohol intake), social environment (e.g., educational and economic opportunities, racial/ethnic discrimination, and neighborhood and work conditions), and access to preventive health-care services (e.g., cancer screening and vaccination) as well as to treatment (through lack of insurance, lack of hospitals in certain areas, etc.), among other environmental differences. Some diseases may also be influenced by genes
Gênes
Gênes is the name of a département of the First French Empire in present Italy, named after the city of Genoa. It was formed in 1805, when Napoleon Bonaparte occupied the Republic of Genoa. Its capital was Genoa, and it was divided in the arrondissements of Genoa, Bobbio, Novi Ligure, Tortona and...

 which differ in frequency between groups, such as sickle-cell anemia, which occurs overwhelmingly among some black
Black people
The term black people is used in systems of racial classification for humans of a dark skinned phenotype, relative to other racial groups.Different societies apply different criteria regarding who is classified as "black", and often social variables such as class, socio-economic status also plays a...

 populations, although the significance in clinical medicine of race categories as a proxy for exact genotype
Genotype
The genotype is the genetic makeup of a cell, an organism, or an individual usually with reference to a specific character under consideration...

s of individuals has been questioned.

Health disparities

Health disparities
Health disparities
Health equity refers to the study of differences in the quality of health and health care across different populations....

 refer to gaps in the quality of health
Health
Health is the level of functional or metabolic efficiency of a living being. In humans, it is the general condition of a person's mind, body and spirit, usually meaning to be free from illness, injury or pain...

 and health care
Health care
Health care is the diagnosis, treatment, and prevention of disease, illness, injury, and other physical and mental impairments in humans. Health care is delivered by practitioners in medicine, chiropractic, dentistry, nursing, pharmacy, allied health, and other care providers...

 across racial and ethnic groups. The US Health Resources and Services Administration
Health Resources and Services Administration
The Health Resources and Services Administration , is an agency of the U.S. Department of Health and Human Services located in Rockville, Maryland...

 defines health disparities as "population-specific differences in the presence of disease, health outcomes, or access to health care." Health is measured through variables such as life expectancy and incidence of diseases.

Single gene disorders

There are many single gene genetic disorder
Genetic disorder
A genetic disorder is an illness caused by abnormalities in genes or chromosomes, especially a condition that is present from before birth. Most genetic disorders are quite rare and affect one person in every several thousands or millions....

s that differ in frequency between different popultions. Some examples are discussed below.

Cystic fibrosis
Cystic fibrosis
Cystic fibrosis is a recessive genetic disease affecting most critically the lungs, and also the pancreas, liver, and intestine...

 is the most common life-limiting autosomal recessive disease among people of European heritage.

Sickle-cell anemia is most prevalent in populations of sub-Saharan African ancestry, but it is also common among Latin-American, Indian, Saudi Arab, and Mediterranean populations such as Turkey, Greece, and Italy.

Tay-Sachs Disease
Tay-Sachs disease
Tay–Sachs disease is an autosomal recessive genetic disorder...

 is an autosomal recessive disorder that is more frequent among Ashkenazi Jews
Ashkenazi Jews
Ashkenazi Jews, also known as Ashkenazic Jews or Ashkenazim , are the Jews descended from the medieval Jewish communities along the Rhine in Germany from Alsace in the south to the Rhineland in the north. Ashkenaz is the medieval Hebrew name for this region and thus for Germany...

 than among other Jewish groups and non-Jewish populations.

Hereditary hemochromatosis is most common among those of Northern European ancestry, in particular those of Celtic descendent.

Lactose intolerance
Lactose intolerance
Lactose intolerance, also called lactase deficiency or hypolactasia, is the inability to digest and metabolize lactose, a sugar found in milk...

 is another examples of single gene genetic disorders that differ in frequency between populations.

Multifactorial polygenic diseases

These are many diseases which differ in frequency between different populations.
Diseases that differ in frequency among different populations.
Health defined group High-risk groups Low-risk groups Reference(s)
Atrial fibrillation
Atrial fibrillation
Atrial fibrillation is the most common cardiac arrhythmia . It is a common cause of irregular heart beat, identified clinically by taking a pulse. Chaotic electrical activity in the two upper chambers of the heart result in the muscle fibrillating , instead of achieving coordinated contraction...

 
European Americans African Americans
Carotid artery disease  European Americans African Americans
Coronary artery disease  European Americans African Americans, West African men
Dementia
Dementia
Dementia is a serious loss of cognitive ability in a previously unimpaired person, beyond what might be expected from normal aging...

 
African Americans European Americans
Focal segmental glomerulosclerosis
Focal segmental glomerulosclerosis
Focal segmental glomerulosclerosis is a cause of nephrotic syndrome in children and adolescents, as well as an important cause of kidney failure in adults.It is also known as "focal glomerular sclerosis" or "focal nodular glomerulosclerosis"....

 
African Americans European Americans
Hepatitis C
Hepatitis C
Hepatitis C is an infectious disease primarily affecting the liver, caused by the hepatitis C virus . The infection is often asymptomatic, but chronic infection can lead to scarring of the liver and ultimately to cirrhosis, which is generally apparent after many years...

 clearance
European Americans African Americans
HIV
HIV
Human immunodeficiency virus is a lentivirus that causes acquired immunodeficiency syndrome , a condition in humans in which progressive failure of the immune system allows life-threatening opportunistic infections and cancers to thrive...

 progression
African Americans European Americans
HIV vertical transmission European Americans African Americans
Hypertension
Hypertension
Hypertension or high blood pressure is a cardiac chronic medical condition in which the systemic arterial blood pressure is elevated. What that means is that the heart is having to work harder than it should to pump the blood around the body. Blood pressure involves two measurements, systolic and...

 
African Americans, West Africans Europeans
Hypertensive heart disease
Hypertensive heart disease
Hypertensive heart disease is any of a number of complications of arterial hypertension that affects the heart.-Symptoms:* Fatigue* Cardiomegaly* Irregular pulse* Swelling of feet* Weight gain* Nausea* Shortness of breath...

 
African Americans European Americans
Hypertensive retinopathy
Hypertensive retinopathy
Hypertensive retinopathy is damage to the retina due to high blood pressure .-Pathophysiology:The retina is one of the "target organs" that are damaged by sustained hypertension....

 
African Americans European Americans
Intracranial haemorrhage  African Americans European Americans
Lupus nephritis
Lupus nephritis
Lupus nephritis is an inflammation of the kidney caused by systemic lupus erythematosus , a disease of the immune system. Apart from the kidneys, SLE can also damage the skin, joints, nervous system and virtually any organ or system in the body....

 with systemic lupus erythematosus
Lupus erythematosus
Lupus erythematosus is a category for a collection of diseases with similar underlying problems with immunity . Symptoms of these diseases can affect many different body systems, including joints, skin, kidneys, blood cells, heart, and lungs...

 
African Americans European Americans
Lung cancer
Lung cancer
Lung cancer is a disease characterized by uncontrolled cell growth in tissues of the lung. If left untreated, this growth can spread beyond the lung in a process called metastasis into nearby tissue and, eventually, into other parts of the body. Most cancers that start in lung, known as primary...

 
African Americans European Americans
Multiple sclerosis
Multiple sclerosis
Multiple sclerosis is an inflammatory disease in which the fatty myelin sheaths around the axons of the brain and spinal cord are damaged, leading to demyelination and scarring as well as a broad spectrum of signs and symptoms...

 
Europeans African Americans, Turkmens, Uzbeks, Native Siberians, New Zealand Maoris
Myeloma  African Americans European Americans
Non-insulin dependent diabetes  African Americans, West Africans, Peninsular Arabs, Pacific Islanders and Native Americans European Americans, Europeans
Obesity
Obesity
Obesity is a medical condition in which excess body fat has accumulated to the extent that it may have an adverse effect on health, leading to reduced life expectancy and/or increased health problems...

 
African women, Native Americans, Pacific Islanders, Aboriginal Australians European Americans, Europeans
Osteoporosis
Osteoporosis
Osteoporosis is a disease of bones that leads to an increased risk of fracture. In osteoporosis the bone mineral density is reduced, bone microarchitecture is deteriorating, and the amount and variety of proteins in bone is altered...

 
European Americans African Americans
Pregnancy
Pregnancy
Pregnancy refers to the fertilization and development of one or more offspring, known as a fetus or embryo, in a woman's uterus. In a pregnancy, there can be multiple gestations, as in the case of twins or triplets...

-related death
African Americans European Americans
Prostate cancer
Prostate cancer
Prostate cancer is a form of cancer that develops in the prostate, a gland in the male reproductive system. Most prostate cancers are slow growing; however, there are cases of aggressive prostate cancers. The cancer cells may metastasize from the prostate to other parts of the body, particularly...

 
Africans and African Americans European Americans
Renal disease, end stage Native Americans and African populations European Americans, Europeans
Skin cancer
Skin cancer
Skin neoplasms are skin growths with differing causes and varying degrees of malignancy. The three most common malignant skin cancers are basal cell cancer, squamous cell cancer, and melanoma, each of which is named after the type of skin cell from which it arises...

 
Europeans  
Stroke
Stroke
A stroke, previously known medically as a cerebrovascular accident , is the rapidly developing loss of brain function due to disturbance in the blood supply to the brain. This can be due to ischemia caused by blockage , or a hemorrhage...

 
African Americans European Americans
Systemic lupus erythematosus
Lupus erythematosus
Lupus erythematosus is a category for a collection of diseases with similar underlying problems with immunity . Symptoms of these diseases can affect many different body systems, including joints, skin, kidneys, blood cells, heart, and lungs...

 
African Americans, West Africans, Native Americans Europeans
Systemic sclerosis  African Americans European Americans

Medicines targeted at specific races

Race-based medicine is the term for medicines that are targeted at specific ethnic clusters which are shown to have a propensity for a certain disorder. The first example of this in the U.S. was when BiDil, a medication for congestive heart failure, was licensed specifically for use in American patients that self-identify as black. Previous studies had shown that African American patients with congestive heart failure generally respond less effectively to traditional treatments than white patients with similar conditions. After two trials, BiDil was licensed exclusively for use in African American patients. Critics have argued that this particular licensing was unwarranted, since the trials did not in fact show that the drug was more effective in African Americans than in other groups, but merely that it was more effective in African Americans thanother similar drug. It was also only tested in African American males, but not in any other racial groups or among women. This peculiar trial and licensing procedure has prompted suggestions that the licensing was in fact used as a race based advertising scheme.

Environmental explanations

In multiracial societies such as the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

, racial groups differ greatly in regard to social and cultural factors such as socioeconomic status
Socioeconomic status
Socioeconomic status is an economic and sociological combined total measure of a person's work experience and of an individual's or family’s economic and social position in relation to others, based on income, education, and occupation...

, healthcare, diet, and education. There is also the presence of racism
Racism
Racism is the belief that inherent different traits in human racial groups justify discrimination. In the modern English language, the term "racism" is used predominantly as a pejorative epithet. It is applied especially to the practice or advocacy of racial discrimination of a pernicious nature...

 which some see as a very important explaining factor. Some argue that for many diseases racial differences would disappear if all environmental factors could be controlled for. See the article about race and health in the United States
Race and health in the United States
Research on race and health in the United States shows many health disparities between the different racial/ethnic groups. The possible causes, such as genetics, socioeconomic factors, and racism, continue to be debated.-Overview:...

 for a discussion of such factors. These factors may or may not be appropriate in other nations.

Ethnic minorities may also have specific health care needs which need to be taken into consideration by health services in order to tackle health disparities.

Evolutionary explanations

Genes may be under strong selection in response to local diseases. For example, people who are duffy negative
Duffy antigen
Duffy antigen/chemokine receptor also known as Fy glycoprotein or CD234 is a protein that in humans is encoded by the DARC gene....

 tend to have higher resistance to malaria. Most Africans are duffy negative and most non-Africans are duffy positive. A number of genetic diseases more prevalent in malaria-afflicted areas may provide some genetic resistance to malaria
Genetic resistance to malaria
Genetic resistance to malaria occurs through both modifications of the immune system that enhance immunity to this infection and also by changes in human red blood cells that hinder the malaria parasite's ability to invade and replicate within these cells...

 including sickle cell disease, thalassaemias, glucose-6-phosphate dehydrogenase
Glucose-6-phosphate dehydrogenase
Glucose-6-phosphate dehydrogenase is a cytosolic enzyme in the pentose phosphate pathway , a metabolic pathway that supplies reducing energy to cells by maintaining the level of the co-enzyme nicotinamide adenine dinucleotide phosphate...

, and possibly others.

Many theories about the origin of the Cystic fibrosis have suggested that it provides a heterozygote advantage
Heterozygote advantage
A heterozygote advantage describes the case in which the heterozygote genotype has a higher relative fitness than either the homozygote dominant or homozygote recessive genotype. The specific case of heterozygote advantage is due to a single locus known as overdominance...

 by giving resistance to diseases earlier common in Europe.

In earlier research a common theory was the "common disease-common variant" model. It argues that for common illnesses, the genetic contribution comes from the additive or multiplicative effects of gene variants that each one is common in the population. Each such gene variant is argued to cause only a small risk of disease and no single variant is enough to cause the disease. An individual must have many of these common gene variants in order for the risk of disease to be substantial. More recent research indicates that the "common disease-rare variant" may be a better explanation for many common diseases. In this model, rare but higher-risk gene variants cause common diseases. This model may be particularly relevant for diseases that reduces fertility. In contrast, for common genes associated with common disease to persist they must either have little effect during the reproductive period of life (like Alzheimer's disease) or provide some advantage in the original environment (like genes causing autoimmune diseases also providing resistance against infections). In either case varying frequencies of genes variants in different populations may be an explanation for health disparities. Genetic variants associated with Alzheimer's disease, deep venous thrombosis, Crohn disease, and type 2 diabetes appear to adhere to "common disease-common variant" model.

Gene flow

Gene flow
Gene flow
In population genetics, gene flow is the transfer of alleles of genes from one population to another.Migration into or out of a population may be responsible for a marked change in allele frequencies...

 and admixture
Admixture
Admixture can refer to:* Genetic admixture, the result of interbreeding between two or more previously isolated populations within a species.* Racial admixture, admixture between humans, also referred to as Miscegenation* Hybrid...

 can also have an effect on relationships between race and race-linked disorders. Multiple sclerosis, for example, is typically associated with people of European descent, but due to admixture African Americans have elevated levels of the disorder relative to Africans.

Some diseases and physiological variables vary depending upon their admixture ratios. Examples include measures of insulin
Insulin
Insulin is a hormone central to regulating carbohydrate and fat metabolism in the body. Insulin causes cells in the liver, muscle, and fat tissue to take up glucose from the blood, storing it as glycogen in the liver and muscle....

 functioning and obesity
Obesity
Obesity is a medical condition in which excess body fat has accumulated to the extent that it may have an adverse effect on health, leading to reduced life expectancy and/or increased health problems...

.

Gene interactions

The same gene variant, or group of gene variants, may produce different effects in different populations depending on differences in the gene variants, or groups of gene variants, they interact with. One example is the rate of progression to AIDS
AIDS
Acquired immune deficiency syndrome or acquired immunodeficiency syndrome is a disease of the human immune system caused by the human immunodeficiency virus...

 and death in HIV
HIV
Human immunodeficiency virus is a lentivirus that causes acquired immunodeficiency syndrome , a condition in humans in which progressive failure of the immune system allows life-threatening opportunistic infections and cancers to thrive...

–infected patients. In Caucasians and Hispanics, HHC haplotype
Haplotype
A haplotype in genetics is a combination of alleles at adjacent locations on the chromosome that are transmitted together...

s were associated with disease retardation, particularly a delayed progression to death. In contrast, for African Americans, possession of HHC haplotypes was associated with disease acceleration.

Controversy regarding race in biomedicine

There is a controversy regarding race as a method for classifying humans. Some see it as a purely social construct. Others see it as a biological reality reflecting average genetic group differences.

New interest in human biological variation has resulted in a resurgence of the use of race in biomedicine. The main impetus for this development is the possibility of improving the prevention and treatment of certain disease
Disease
A disease is an abnormal condition affecting the body of an organism. It is often construed to be a medical condition associated with specific symptoms and signs. It may be caused by external factors, such as infectious disease, or it may be caused by internal dysfunctions, such as autoimmune...

s by predicting hard-to-ascertain factors, such as genetically conditioned health factors, on the basis of more easily ascertained characteristics such as phenotype and racial self-identification. Since medical judgment often involves decision-making under uncertain conditions, many doctors consider it useful to take race into account when treating disease because diseases and treatment responses tend to cluster by geographic ancestry. The discovery that more diseases than previously thought correlate with racial identification have further sparked the interest in using race as a proxy for bio-geographical ancestry and genetic buildup.

Race in medicine is used as an approximation for more specific genetic and environmental risk factors. Race is thus partly a surrogate for environmental factors such as differences in socioeconomic status that are known to affect health. It is also an imperfect surrogate for ancestral geographic regions and differences in gene frequencies between different ancestral populations and thus differences in genes that can affect health. This can give an approximation of probability for disease or for preferred treatment, although the approximation is less than perfect.

Taking the example of sickle-cell disease
Sickle-cell disease
Sickle-cell disease , or sickle-cell anaemia or drepanocytosis, is an autosomal recessive genetic blood disorder with overdominance, characterized by red blood cells that assume an abnormal, rigid, sickle shape. Sickling decreases the cells' flexibility and results in a risk of various...

, in an emergency room
Emergency department
An emergency department , also known as accident & emergency , emergency room , emergency ward , or casualty department is a medical treatment facility specialising in acute care of patients who present without prior appointment, either by their own means or by ambulance...

, knowing the geographic origin of a patient may help a doctor doing an initial diagnosis if a patient presents with symptoms compatible with this disease. This is unreliable evidence with the disease being present in many different groups as noted above with the trait also present in some Mediterranean European populations. Definitive diagnosis comes from examining the blood of the patient. In the US, screening for sickle cell anemia is done on all newborns regardless of race.

The continued use of racial categories has been criticized. Apart from the general controversy regarding race, some argue that the continued use of racial categories in health care and as risk factors could result in increased stereotyping
Stereotype
A stereotype is a popular belief about specific social groups or types of individuals. The concepts of "stereotype" and "prejudice" are often confused with many other different meanings...

 and discrimination in society and health services. On the other hand, also some of those who are critical of race as a biological concept see race as socially meaningful group that is important to study epidemiologically in order to reduce disparities.

David Williams (1994) argued, after an examination of articles in the journal Health Services Research during the 1966-90 period, that how race was determined and defined was seldom described. At a minimum, researchers should describe if race was assessed by self-report, proxy report, extraction from records, or direct observation. Race was also often used questionable, such as an indicator of socioeconomic status. Racial genetic explanations may be overemphasized, ignoring the interaction with and the role of the environment.

There is general agreement that a goal of health-related genetics should be to move past the weak surrogate relationships of racial health disparity and get to the root causes of health and disease. This includes research which strives to analyze human genetic variation in smaller groups than races across the world. One such method is called ethnogenetic layering. It works by focusing on geographically identified microethnic groups. For example, in the Mississippi Delta region ethnogenetic layering might include such microethnic groups as the Cajun (as a subset of European Americans), the Creole and Black groups [with African origins in Senegambia, Central Africa and Bight of Benin] (as a subset of African Americans), and Choctaw, Houmas, Chickasaw, Coushatta, Caddo, Atakapa, Karankawa and Chitimacha peoples (as subsets of Native American Indians).

Better still may be individual genetic assessment of relevant genes. However, until cheaper and more widely available methods of genetic analysis are commonplace, the consideration of race remains a worthwhile practice for many doctors and researchers. Even when such methods become commonly available, race will continue to be important when looking at groups instead of individuals such as in epidemiologic research.

Association studies

One area in which population categories can be important considerations in genetics research is in controlling for confounding between population genetic substructure, environmental exposures, and health outcomes. Association studies can produce spurious results if cases and controls have differing allele frequencies for genes that are not related to the disease being studied, although the magnitude of its problem in genetic association studies is subject to debate. Various techniques detect and account for population substructure, but these methods can be difficult to apply in practice.

Population genetic substructure also can aid genetic association studies. For example, populations that represent recent mixtures of separated ancestral groups can exhibit longer-range linkage disequilibrium
Linkage disequilibrium
In population genetics, linkage disequilibrium is the non-random association of alleles at two or more loci, not necessarily on the same chromosome. It is also referred to as to as gametic phase disequilibrium , or simply gametic disequilibrium...

 between susceptibility alleles and genetic markers than is the case for other populations. Genetic studies can use this disequilibrium to search for disease alleles with fewer markers than would be needed otherwise. Association studies also can take advantage of the contrasting experiences of racial or ethnic groups, including migrant groups, to search for interactions between particular alleles and environmental factors that might influence health.

Human genome projects

The Human Genome Diversity Project
Human Genome Diversity Project
The Human Genome Diversity Project was started by Stanford University's Morrison Institute and a collaboration of scientists around the world. It is the result of many years of work by Luigi Cavalli-Sforza, one of the most cited scientists in the world, which has published extensively in the use...

 has collected genetic samples from 52 indigenous populations. This sampling has been controversial because some fear that racists might use the results, because the sampling might overemphasize genetic distinctions, because of informed consent issues, and patenting issues.

Several other genome project
Genome project
Genome projects are scientific endeavours that ultimately aim to determine the complete genome sequence of an organism and to annotate protein-coding genes and other important genome-encoded features...

s also studies populations from around the world but often not as diverse.

Race and health in the United States

Research on Race and health in the United States
Race and health in the United States
Research on race and health in the United States shows many health disparities between the different racial/ethnic groups. The possible causes, such as genetics, socioeconomic factors, and racism, continue to be debated.-Overview:...

 shows many health disparities between the different racial/ethnic groups. The possible causes, such as genetics, socioeconomic factors, and racism, continue to be debated.

See also

  • Health and intelligence
    Health and intelligence
    Health can affect intelligence in various ways. This is one of the most important factors in understanding the origins of human group differences in IQ test scores and other measures of cognitive ability...

  • Human stature#Average height around the world
  • List of countries by life expectancy
  • Health disparities
    Health disparities
    Health equity refers to the study of differences in the quality of health and health care across different populations....

  • Center for Minority Health
    Center for Minority Health
    The Center for Minority Health , part of The University of Pittsburgh Graduate School of Public Health, was established in 1994 through a grant from the Richard King Mellon Foundation...

  • Pharmacogenomics
    Pharmacogenomics
    Pharmacogenomics is the branch of pharmacology which deals with the influence of genetic variation on drug response in patients by correlating gene expression or single-nucleotide polymorphisms with a drug's efficacy or toxicity...

  • Medical genetics
    Medical genetics
    Medical genetics is the specialty of medicine that involves the diagnosis and management of hereditary disorders. Medical genetics differs from Human genetics in that human genetics is a field of scientific research that may or may not apply to medicine, but medical genetics refers to the...

  • Ethnic bioweapon
    Ethnic bioweapon
    An ethnic bioweapon aims to harm only or primarily persons of specific ethnicities or genotypes.- History of ethnic bioweapons :One of the first fictional discussions of ethnic weapons is in Robert A...

  • Social determinants of health
    Social determinants of health
    Social determinants of health are the economic and social conditions under which people live which determine their health. They are "societal risk conditions", rather than individual risk factors that either increase or decrease the risk for a disease, for example for cardiovascular disease and...

  • Medical genetics of Jews
  • Personal genomics
    Personal genomics
    Personal genomics is the branch of genomics concerned with the sequencing and analysis of the genome of an individual. The genotyping stage employs different techniques, including single-nucleotide polymorphism analysis chips , or partial or full genome sequencing...

  • Hispanic Paradox
    Hispanic Paradox
    The Hispanic Paradox, or Latino Paradox, also known as the "Epidemiologic Paradox," refers to the epidemiological finding that Hispanic and Latino Americans tend to have health outcomes that paradoxically are comparable to, or in some cases better than, those of their U.S. white counterparts, even...

  • :Category:Human genome projects

External links


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