Health Disparity

A health disparity can be defined from a sociological, population-specific, or biopsychosocial perspective.

For example, from a sociological perspective, health disparity can be viewed as a chain of events signified by differences in (1) environment; (2) access to, utilization of, and quality of care; (3) health status; and (4) health outcome.

On the other hand, in its broadest sense, a health disparity can be defined as a “population-specific difference in not only disease, but health outcomes, or access to health care” ( ). In fact, the first National Institutes of Health (NIH) Working Group on Health Disparities succinctly narrowed the definition somewhat by defining health disparities as “differences in the incidence, prevalence, mortality, and burden of disease and other adverse health conditions that exist among specific population groups in the US” ( ; ). It is essential to remember that because the impact of health care on health disparities is an important factor, a defi­nition of racial and ethnic health care disparities was provided by the Institute of Medicine’s Committee on Understanding and Eliminating Racial and Ethnic Disparities in Health Care ( ). The committee unequivocally noted that a health disparity “more likely than not is a racial and ethnic difference in the quality of health care usually arising as a result of access-related factors or clinical needs, preferences and appropriateness of the intervention” ( ). In fact, the committee unequivocally noted that disparities in health care for the most part are consistent regardless of the nature of the illness or the time of services rendered ( ).

It is interesting to note that neither the sociological nor population-specific definitions allow for the inclusion of biological variations that may occur in groups of people regardless of race, ethnicity, socioeconomic status, and access to care issues. With this thought in mind, another approach to health disparity from a biopsychosocial perspective is offered that works in tandem with the concept of biological variations. From a biopsychosocial perspective, genes and biology, environment, and behavior all come together in a cataclysmic way to create a health disparity ( ; Giger & Davidhizar). It is essential to note that socioeconomic status plays a major contributing factor in unequal treatment, particularly where ethnic minorities are concerned. Although this definition does take into account the issue of vulnerability or race and ethnicity, socioeconomic status, geographical location, and access to care issues ( ), noted that even if income levels were standardized and all impediments regarding access to care were eliminated, disparities in health outcomes might still exist. They contend that this argument gives credence to the need to eliminate cultural incompetence among health care providers. The biopsychosocial perspective does not negate the fact that certain groups, including specific racial and ethnic groups, persons residing in certain geographic locations, the poor and underserved, and the disabled, are more likely to suffer disproportionately from health disparities ( ). It is also interesting to note that the term disparity is almost exclusively used in the United States, whereas the terms health inequality or inequity are more commonly used outside of the United States.

Health Care Inequality

Inequality, particularly when referring to health care, is a term used to refer to differences in age, rank, condition, lack of excellence in treatment, or dissimilitude (vast differences) in services available. Inequity is similarly defined as a condition of “being unequal” or “lack of opportunity, treatment or status.” Yet another view of the term health disparity is that in the context of public health and the social sciences, the term has begun to take on a meaning of injustice ( ). In fact, contend that in the United States, there is growing concern that even when there are equivalent levels of access to care, most racial and ethnic minorities continue to experience a lower quality of health services and are therefore less likely to receive needed routine medical procedures than their White counterparts. For example, African-Americans are less likely to receive peritoneal dialysis and kidney transplants for end-stage renal disease than their White counterparts ( ; ; ). Similarly, some data suggest that African-American and Hispanic clients with long-bone fractures who are seen in the emergency department are far less likely than their White counterparts to receive necessary analgesics to suppress the pain ( ). Yet another example of health care disparities includes studies suggesting that African-American Medicare patients with congestive heart failure or pneumonia, for example, are more likely to receive a poorer quality of care than are their White counterparts ( ; ).

Body Structure

One category of difference between racial groups is body structure, which includes both body size and body shape. Newborn body proportions differ among racial groups. Although research on this topic remains scanty, it has been postulated that newborn body proportions appear to be genetically programmed to conform to the pelvic shape of the mother ( ; ).

Body structure as well as bone density also differs among adults. For example, the prevalence of osteoporosis and the incidence of vertebral fractures are both reported to be substantially lower in African-American women than in White American women ( ; ; ). This finding is generally attributed to racial differences in adult bone mass ( ).

Among adults, bone density is greater in African-Americans than in White Americans of either sex ( ). However, differences in adult bone density are not necessarily confined to these two racial groups. In fact, the bone density of adult Polynesians is reported to be greater than that of age-matched Whites ( ). In contrast, Asian Americans generally have lower values for bone density than other racial groups ( ). Biological markers that account for the variations in adult bone mass among racial groups are unknown. In addition, the time of life at which these differences are manifested is uncertain. According to , prepubertal African-American children tend to have higher values for bone density than do their White counterparts. Some researchers ( ) have speculated that such findings indicate that racial differences in skeletal mass develop early in childhood and persist throughout life.

In regard to body structure and size, the face is perhaps one of the most fascinating areas of the body because it has many parts that combine to make the whole. The face tends to be the one prominent area that can visibly categorize people by race. For example, eyelids vary from racial group to racial group. In some racial groups the eyelids droop over the cartilage plate above the eye, and in other racial groups the eyelids do not droop. The epicanthic fold, another variation of the eyelids, is found predominantly in persons with Asian characteristics but may be present in other racial groups.

Ears are another fascinating part of the face because they have a variety of shapes. Earlobes can be free and floppy or attached close to the face as if the intent were to make sure the lobe stayed in place. Earlobes that are free and floppy are very handy for attaching earrings. When earlobes are attached, they are the least defined, and wearing objects such as earrings may be difficult.

Noses come in all sizes and shapes; however, nose size and shape correlate directly with one’s racial ancestry. It has been postulated that small noses were an evolutionary result of living in cold climates, such as the classic Asian nose, and that noses with high bridges were a result of living in climates that were dry, such as the classic Iranian and American Indian noses. People who lived in moist, hot climates developed broad, flat noses, such as those found on Africans and African-Americans ( ).

Teeth offer another important variation in body size and shape. Tooth size, which is important because the teeth help shape the size of the lower face, varies among racial groups. For example, Australian aborigines have the largest teeth in the world, as well as four extra molars. Asian Americans and African-Americans have very large teeth, whereas White Americans have very small teeth. People with very large teeth tend to have their jaws projecting beyond the upper part of the face. This projection tends to be a normal variation and not an orthodontic problem. There is also a tendency among some racial groups for fewer teeth. For example, some racial groups do not have a third molar or maxillary lateral incisors. Peg teeth are sometimes a step in the evolutionary process that facilitates the presence or absence of a particular type of tooth ( ; ).

As teeth vary among racial groups, so do tongues. The most common variances are scrotal tongues, which occur in 5% of the population in some racial groups; geographic tongues, which occur in 3% of the population in some racial groups; and fissured tongues, which occur in 5% to 40% of the population in some racial groups ( ).

The mandibular or palatine torus is also of concern to the nurse when inspecting the mouth. The torus is a bony protuberance, and the palatine torus occurs on the midline of the palate, whereas the mandibular torus occurs as a lump on the inner side of the mandible near the second molar. Tori are fairly common, with palatine tori occurring in up to 25% of the population in most racial groups studied. Mandibular tori occur in 7% of Whites, 2% of African-Americans, and 40% of Asians ( ).

Another variation in body size and structure is attributable to muscle size and mass. In certain racial groups, specific muscles are absent altogether. The peroneus tertius muscle, which is found in the foot, and the palmaris longus muscle, which is found in the wrist, are absent in individuals in some racial groups. However, muscle absence in general does not appear to be more prevalent in any particular racial group, nor does absence of a particular muscle correspond with absence of another muscle.

Numerous studies have investigated inheritability of stature ( ; ). In general, the studies conclude that people vary in height as a result of race and that in the United States, African-Americans and White Americans are the tallest, American Indians are either similar in height or a few inches shorter than Mexican Americans, and Asian Americans are the shortest. Individuals of higher socioeconomic status in all ethnic groups are taller ( ; ). In regard to physical growth and developmental rates, African-Americans are generally advanced, whereas Asians are generally lower when these groups are compared with White norms.

Body Weight

Weight differs in individuals both by race and by gender. African-Americans and Whites are less similar in weight than they are in height. This is believed to occur because African-Americans have heavier bone and muscle mass than Whites ( ; ). On the average, African-American men weigh less than their White counterparts (166.1 lb compared to 170.6 lb, respectively) ( ). In stark contrast, African-American women are consistently heavier at every age group than their White American counterparts (149.6 lb compared to 137.0 lb, respectively). In addition, African-American women average about 20 lb heavier than their White American counterparts from 35 to 65 years of age ( ). Similarly, Mexican American Whites, on the average, weigh more than non-Hispanic Whites as a result of truncal fat ( ). On average, obesity is more pronounced in the lower class, less pronounced in the middle class compared with their lower-class counterparts, and even less pronounced in the upper class compared with their middle-class counterparts ( ).

If the health care statistics in Healthy People 2010 and 2020 are dismal for African-American, Hispanic, and American Indian women and men, they are even worse for their children ( ). If being overweight is a common problem in the general U.S. population, it is said to be at epidemic proportions for children in this country ( ). Data from the indicated that the prevalence of overweight among children was higher among non-Hispanic Black (15.1%) and Hispanic children (15.1%) than non-Hispanic White children (10.3%) and higher among non-Hispanic Black female (11.1%) and Hispanic female (11.2%) than White female (6.2%) students ( ; ). In a comparison of obesity rates in male students, the highest rate was in Hispanic (21.3%) and non-Hispanic Blacks (18.2%) than in Whites (14.0%). Nonetheless, childhood obesity continues to increase steadily and rapidly among African-American children ( ). Some researchers conclude that childhood obesity often serves as a primary marker for high-risk dietary and physical inactivity practices ( ). Childhood obesity can also contribute to the development of metabolic syndrome (syndrome X), also referred to as insulin resistance.

Skin Color

When working with people from diverse cultural backgrounds, the nurse should understand how different races evolved in relation to the environment. Biological differences noted in skin color may be attributable to the biological adjustments a person’s ancestors made in the environment in which they lived. For example, it has been scientifically postulated that the original skin color of humans was black ( ; ) and that white skin was the result of mutation and environmental pressures exerted on persons living in cold, cloudy northern Europe. The mutation is believed to have occurred because light skin was better able to synthesize vitamin D, particularly on cloudy days. It is believed that black skin became a neutral trait in climates where protection from the sun and heat of the tropics was not a factor ( ; ).

Skin color is probably the most significant biological variation in terms of nursing care. Nursing care delivery is based on accurate client assessment, and the darker the client’s skin, the more difficult it becomes to assess changes in color. When caring for clients with highly pigmented skin, the nurse must first establish the baseline skin color, and daylight is the best light source for doing so. If possible, dark-skinned clients should always be given a bed by a window to provide access to sunlight. When daylight is not available to assess skin color, a lamp with at least a 60-watt bulb should be used. To establish the baseline skin color, the nurse must observe skin surfaces that have the least amount of pigmentation, which include the volar surfaces of the forearms, the palms of the hands, the soles of the feet, the abdomen, and the buttocks. When observing these areas, the nurse should look for an underlying red tone, which is typical of all skin, regardless of how dark its color. Absence of this red tone in a client may indicate pallor. Additional areas that are important to assess in dark-skinned clients include the mouth, the conjunctivae, and the nail beds. Generally speaking, the darkness of the oral mucosa correlates with the client’s skin color. The darker the skin, the darker the mucosa; nevertheless, the mucosa is lighter than the skin.

The nurse must be aware that oral hyperpigmentation can occur on the tongue and the mucosa and can alter the value of the oral mucosa as a site for observation. The occurrence of oral hyperpigmentation is directly related to the darkness of a person’s skin. Oral hyperpigmentation appears in 50% to 90% of African-Americans, compared with 10% to 50% of Whites. Another important consideration for the nurse is the appearance of a hard palate because it takes on a yellow discoloration, particularly in the presence of jaundice. The hard palate is frequently affected by hyperpigmentation in a manner similar to that of the oral mucosa and the tongue. The nurse should also assess the lips because they may be helpful in assessing skin-color changes (such as jaundice or cyanosis). It is important for the nurse to remember, however, that the lips of some Black people have a natural bluish hue ( ; ). Thus, it is important for the nurse to have established the baseline color of the lips if they are to be of value in detecting cyanosis ( ; ).

It is also important for the nurse to establish the normal color of the conjunctivae when working with persons from transcultural populations. The conjunctivae will reflect the color changes of cyanosis or pallor and are a good site for observing petechiae. Another excellent source for determining the presence of jaundice is the sclera. The nurse should first establish a baseline color for the sclerae because the sclerae of dark-skinned persons often have a yellow coloration caused by subconjunctival fatty deposits. A common finding in persons with highly pigmented skin is the presence of melanin deposits or “freckles” on the sclerae.

The final area of assessment should be the nail beds, which are useful for detecting cyanosis or pallor. In dark-skinned persons, it is difficult to assess the nail beds because they may be highly pigmented, thick, or lined or contain melanin deposits. Regardless of color, for baseline assessment, it is important for the nurse to notice how quickly the color returns to the nail bed after pressure has been released from the free edge of the nail. A slower return of color to the nail bed may indicate cyanosis or pallor. It is also difficult to detect rashes, inflammations, and ecchymoses in dark-skinned persons. It may be necessary to palpate rashes in dark-skinned persons because rashes may not be readily visible to the eye. When palpating the skin for rashes, the nurse should notice induration and warmth of the area.

Other Visible Physical Characteristics

In addition to looking for pallor and cyanosis, the nurse should note other aberrations in the skin. For example, mongolian spots may be present on the skin of African-American, Asian American, American Indian, or Mexican American newborns. Mongolian spots are bluish discolorations that vary tremendously in size and color and are often mistaken for bruises. Another aberration that is more common in African-Americans than in other racial groups is keloids. These ropelike scars represent an exaggeration of the wound-healing process and may result from any type of trauma, such as surgical incisions, ear piercing, or insertion of an intravenous catheter.

Enzymatic and Genetic Variations

The basic genetic makeup of an individual is determined from the moment of conception. Then, among other things, the upper limits of achievement are set; the “map,” so to speak, is drawn. In other words, a person can be only what he or she is genetically determined to be. More specifically, growth and development cannot go beyond what the genes make possible. An individual will not grow 1 inch taller than the genetic structure allows, regardless of the amount of exercise or vitamins consumed. By the same token, an individual will be no more intelligent than genetic structure allows, despite the amount of tutoring or special schooling the individual receives ( ; ).

In medical terms, a person’s race represents his or her genetic makeup. Although race may be irrelevant in some situations, knowing the racial predisposition to a certain disease is often helpful in evaluating clients and diagnosing their illness, as well as in assessing risks ( ). The genetic and enzymatic predisposition to certain diseases is discussed in this chapter in the Susceptibility to Disease section; lactose intolerance and glucose-6-phosphate dehydrogenase (G-6-PD) deficiency are discussed under Nutritional Deficiencies.

Genes are the working subunits of chemical information that carry a complete set of instructions for making the needed protein for a cell ( ). It is essential to remember that genes contain a particular set of instructions by way of coding for a particular protein ( ). These coded instructions are known as deoxyribonucleic acid (DNA). DNA is composed of two long, paired strands that are spiraled into what is known as a double helix ( ). Although there are only four chemical bases in DNA—adenine, thymine, cytosine, and guanine—the order in which these bases occur determines specifically what information is available in a manner similar to the way in which the specific letters in the alphabet combine to form particular words and connect to form sentences ( ). DNA itself resides in a core, or what is known as the nucleus, of each of the cells in the body. In fact, every human cell, with the one notable exception of mature red blood cells, which have no nucleus, has the same DNA. All somatic cells have 46 molecules of double-stranded DNA. Likewise, each molecule consists of 50 to 250 million bases, which are housed in a chromosome ( ).

There are several levels of genetic investigation, including molecular genetics and cytogenetics. Molecular genetics is the study of genes at a biochemical or cellular level ( ). A gene and its effects are often separable, and, as such, geneticists are able to distinguish the gene responsible for a trait or illness from the actual expression of a particular trait or illness ( ). For example, the genes themselves compose what is termed the genotypes, whereas the actual expression of these genes is called the phenotype . In contrast to molecular genetics, cytogenetics is the study of genes that involves matching phenotypes to chromosomal variants. As the twentieth century progressed, cytogenetics rapidly matured as geneticists built upon the mapping of all four chromosomes of the fruit fly. By 1950, the arduous task of mapping genes on the 22 pairs of autosomes was begun ( ). Today this process of sequencing a genetic map is known as the Human Genome Project ( ). Work relative to the 15-year international Human Genome Project was officially inaugurated in the United States on October 1, 1990, and the purpose of the Human Genome Project was to identify the 3 billion code letters of a representative human genome by the year 2005 ( ). At the same time, geneticists were to identify the exact location of all genes on the sequencing map. On April 14, 2003, work relative to the sequencing of the Human Genome Project was finally completed a full 2 years ahead of schedule ( ).

Another area of genetic study is termed population genetics . Population genetics is the study of allele frequencies in populations ( ). Population genetics is extremely important because human beings tend to marry or mate with people primarily like themselves—that is, the same racial, ethnic, and cultural groups. Because of this, there is a tendency for a frequency of certain alleles in that given population. For example, although 1 of 800 women in the general U.S. population is affected by the BRCA1 breast cancer gene, this figure climbs dramatically to 1 of every 100 women among Ashkenazi Jews ( ).

Today the relative role that genetics plays in understanding the etiology of disease is becoming evident. It is important to remember that all diseases, except for trauma, have a genetic linkage. The earliest introduction to the concept of genetic inheritance comes from the nineteenth-century work of Gregor Mendel. Mendel’s work involved the identification and breeding of a variety of pea plants ( ; ). From his work, Mendel noted that these pea plants had two different expressions of an inherited trait. For example, Mendel noted that when short plants were bred with short plants they were “true breeding”—that is, giving rise to the production of only short plants. However, when tall plants were bred with short plants or another tall plant, the next generation resulted in only tall offspring. This phenomenon indicates that a gene can and does exist in alternative forms. In genetics, these alternative forms are called alleles ( ).

Ordinarily a gene is a stable entity, but over the course of time a gene can suffer a change in sequence ( ). This change is termed a mutation . The new form of the gene is inherited in a stable manner, as in the case of the previous form ( ). When a mutation occurs, the organism carrying the altered gene is called a mutant, whereas the organism that carries the normal, or unaltered, gene is called the wild type. The term wild type is used to describe either the genotype or the phenotype.

To understand how copies of a gene are transmitted, it is necessary to understand that the life cycle of an organism passes through a diploid phase and essentially has two copies of each gene. At conception, one of two copies is passed from the parent to a gamete (a germ cell, egg, or sperm). At this point, the gamete contains one copy of each gene of the organism, and this is called the haploid set . Consequently, the alternative types of gametes produced by the parents unite to form what is called the zygote (the fertilized egg) ( ).

With a mutation, new alleles arise. Generally, when a mutation occurs, the particular frequency is represented by only one copy among all the copies of that particular gene in the population ( ). The probability that a new mutation will survive from one generation to the next is largely dependent on both chance and natural selection. From one generation to the next, depending on chance, allele frequencies fluctuate ( ). This entire phenomenon is termed genetic drift .

When an individual has two identical alleles for a gene, this individual is said to be homozygous for that gene. Similarly, an individual with two different alleles is heterozygous . In other words, a person inherits essentially one allele from each parent. These alleles can be the same or different. Therefore, at any locus on a chromosome pair, there is a gene composed of two alleles. For example, the blood types A, B, and O are the alleles for the ABO blood type locus ( ). If there is only one allele at a particular locus, then the gene is said to be monomorphic . In contrast, when there are multiple alleles at a particular gene locus, the gene is said to be polymorphic ( ). An excellent example of this concept is found in the enzyme deficiency disorder G-6-PD deficiency, which is said to be caused by the most polymorphic genes known, with more than 400 alleles ( ).

In Mendel’s classic work, he noted that each of the genes identified had two alleles, which is suggestive of two obvious expressions. A gene may have many alleles (variants) as a result of changes in any of the hundreds or thousands of DNA base pairs that make up a gene. However, because the concept of DNA and DNA sequencing had not yet been identified, Mendel was able to detect a gene variant only if the phenotype was altered. For example, if a green pea produced a yellow pea, this phenomenon would be a phenotypic alteration ( ). As Mendel continued his work, he noted that in some instances one gene could mask the expression of another. In this case, the gene that masks the expression of the other is considered to be completely dominant, whereas the mask allele is considered to be recessive . An excellent example of this concept was noted when Mendel crossed a “true-breeding” tall plant with a short plant. In this case, the tall plant (or the tall allele) was completely dominant to the short plant (short allele), and thus all the plants in the next generation were tall ( ; ). An inherited trait is said therefore to be either dominant or recessive. Whether this trait is dominant or recessive depends on the particular nature of the phenotype. Often the heterozygote, on a biochemical level, is actually intermediate, or a mixture of the homozygous dominant and homozygous recessive, although the heterozygote and the homozygous-dominant genotypes are indistinguishable ( ; ). For example, in the case of Tay-Sachs, a genetically inherited disease commonly found among Jews, the heterozygote (with one dominant and one recessive allele) actually produces half the normal amount of the enzyme that the gene encodes, yet this amount appears to be sufficient for normal function, and so that person remains as healthy as a person with two dominant alleles. A phenotypic (disease itself) expression of the gene would occur only if a person inherited two recessive alleles.

How a person inherits a particular gene depends on two basic characteristics: (1) the dominant or recessive nature of the allele and (2) the type of chromosome that the gene in question is part of ( ). If a person has dominant alleles—that is, has only one copy of the gene—this dominant allele can affect the phenotype. In contrast, a person who has a recessive allele must have two copies of the gene if the phenotype is to be expressed. For example, the cancer-predisposing alleles BRCA1 and BRCA2 are dominant. Therefore, an individual would need to inherit one copy of the gene from one parent to have a 1 in 2 chance of developing the disease. The second mode of inheritance depends on the chromosome location that the particular gene is a part of. For example, human beings have 46 chromosomes, including two that determine sex—X and Y (sex chromosomes). The presence or absence of a single gene on the Y chromosome is responsible for determining sex. The remaining chromosomes are termed nonsex chromosomes, or autosomes . Specifically, a female has 44 autosomes and two X chromosomes. In contrast, a male has 44 autosomes and one X and one Y chromosome. In other words, there are actually 23 pairs of chromosomes consisting of 22 pairs of autosomes, and one pair of X and Y chromosomes ( ; ). Because there is a difference in sex chromosome constitution, it is believed that genes on the sex chromosomes follow different, sex-linked patterns of inheritances in the two sexes. In the case of X-linked dominant inheritance, it is essential to remember that male-to-male transmission never occurs because men cannot pass their X chromosomes to their sons. In addition, all daughters of an affected male with an X-linked gene will actually receive the gene either in a recessive or a dominant form ( ; ). For example, if the father passes an X-linked recessive gene to his daughter, the daughter will be a carrier. However, if the father passes an X-linked dominant gene to his daughter, the daughter will be affected ( ; ). Thus, modes of inheritance of a particular trait can depend on the recessive and dominant characteristics of the allele or on whether the gene is located on the sex chromosome or on an autosomal chromosome ( ).

To understand the significance of genetics, it is essential to develop an awareness of the relative role of single mendelian traits in humans. Single mendelian traits in humans are associated with disorders or traits linked to a single gene. For example, the most prevalent mendelian disorders are believed to be cystic fibrosis, Tay-Sachs disease, and Duchenne muscular dystrophy ( ). Yet, although these mendelian traits are considered prevalent, they are extremely rare, affecting 1 in 10,000 or fewer births ( ). Today, about 2500 mendelian disorders are known, and some 2500 other identifiable conditions are suspected to be mendelian related because of their recurrence patterns in large families ( ).

Some disease cannot be explained by the single-gene mendelian-trait theory. Although every individual has two alleles for any autosomal gene (one allele for each chromosome), a gene can exist in a given population in more than two allelic forms ( ). This different allele combination often leads to variations in phenotype ( ; ). In addition, there is a difference in the dominance relationship of an allele. For example, as previously indicated, in the case of complete dominance, one allele is expressed, and the other is not. However, in some instances, some genes demonstrate what is termed incomplete dominance, which occurs when the heterozygous phenotype is intermediate between that of either homozygote ( ; ). For example, in the case of familial hypercholesterolemia, an individual with two disease-causing alleles actually lacks the liver receptors that take up cholesterol from the bloodstream ( ). In this case, the phenotype will actually parallel the number of receptors. Individuals with one mutant allele die in young adulthood, and those with two of the wild type (the most common expression of a particular gene in a given population) do not develop this inherited form of heart disease ( ).

Understanding genetics and its transcultural and racial implications is of paramount importance. Understanding race and the genetic implications is also important. There are scientists who recognize only Black, White, and Asians/American Indians as racial groups ( ; ; ). Asians and American Indians are often placed by these scientists in one major group because of some genetic similarities ( ; ). Race is an important term because races of people are not static. What is implied by this is that all races have evolved over time as a direct response to environmental stimuli. Thus the characteristics that define a race will not necessarily define any specific individual from that particular race of people ( ). For example, the Yupik Eskimos are said to have a 75% gene frequency of M in the MN blood system and 61% in the O, 25% in the A, and 16% in the B within the ABO blood groups ( ). These same individuals are believed to have no prevalence for Rh-negative blood ( ). A health care professional working with this group of people might assume incorrectly therefore that the most common array of traits for the Yupiks would be blood types M and O and that these individuals would be invariably Rh positive. Although some Yupiks might actually display this array of traits, it must be remembered that because of genetic heterogeneity, some individual Yupiks might differ ( ).

It has been reported that the incidence of dizygotic twinning is highest in African-Americans, occurring in 4% of births. Dizygotic twinning occurs in approximately 2% of births in Whites and in 0.5% of births in Asians ( ; ).

Some research interpretations ( ) have indicated that the small but persistent differences between the average intelligence quotients (IQs) of African-American children and those of White children reflect a genetic difference. In his classic work, claimed to have controlled for variables, including income and education. He reported that he found a difference in IQ that he believed to indicate a genetic difference. Others have refuted Jensen’s claim ( ). In 1977, Jensen conducted a study of children between 5 and 16 years of age in the rural South, which indicated that the IQs of African-American children, but not those of White children, drop substantially as they grow older. Jensen believed that this contrast between African-Americans and Whites possibly meant that the decrement in IQ was genetically determined. This has not been supported by others’ research.

Drug Interactions and Metabolism

Reactions to drugs vary with race. Some evidence indicates that drugs are metabolized by different races in different ways and at different rates ( ; ). For example, demonstrated that Chinese subjects are more sensitive to the cardiovascular effects of propranolol than White subjects are. In the body there are three classes of reactions to foreign chemicals or drugs: hydrolysis, conjugation, and oxidation ( ; ; ).

A term that is essential to understanding how drugs work in the body is pharmacokinetics, which actually is intended to mean or to determine when a steady state of concentration of drugs and their metabolites is achieved in the body ( ). There are two levels of thought regarding pharmacokinetics. The first is that the pharmacokinetics of medication deals with metabolism, blood levels, absorption, distribution, and excretion. The second level of thought suggests that pharmacokinetics also involves other variables including conjugation, plasma protein binding, and oxidation by the cytochrome P (CYP) enzyme isoforms ( ). Most medications are generally metabolized in two phases. In Phase I, medications are subjected to oxidation and are mediated through the P-450 isozymes. The CYP-450 enzymes actually represent what are termed a superfamily of over 50 heme-containing microsomal drug-metabolizing isozymes ( ; ). CYP-450 is named from the characteristic maximum spectral absorbance at 450 mm in its reduced state ( ; ). The name was changed from 450 mm to CYP. Every portion of the newly named CYP-450 is intended to indicate or specify the nomenclature further. For instance, CYP actually designates the human chromosome P-450, which is then followed by an Arabic number with an asterisk (*), which is intended to indicate allelic variation(s) and thus the new nomenclature ( ). For example, CYP2D6*3 actually belongs to the family 2, as well as the subfamily D. In concert with these factors is that the gene that is actually encoding for the isozyme is 6, whereas the allelic variant is 3 and is preceded with an asterisk (*), further distinguishing it ( ).

Phase II enzymes are transferases and are thought to be necessary to allow endogenous substances to conjugate with drugs and their metabolites. It is important to remember that the CYP-450 enzyme 2D6 (debrisoquine hydroxylase), while an important step to the metabolic pathway for a great number of medications, are also responsible for drug-to-drug interactions ( ). According to , it is essential to understand the CYP-450 system because this knowledge will allow accurate predictions of potential drug interactions and known side effects based on a number of demographic variables for racially/ethnically diverse individuals.

A critical isoform is CYP2D6 because it is essential to metabolism (e.g., with antipsychotics). It is essential to remember that CYP2D6 isoenzyme is responsible for the metabolizing of 25% to 30% of all clinically used medications, which include antidepressants, β-blockers, antipsychotics, morphine derivatives, and a host of other drugs ( ). It is also interesting to note that the CYP2D6 isoenzyme was actually discovered in relationship to the polymorphic relation of debrisoquine, an antihypertensive agent. In fact, the discovery showed that there were two distinct phenotypes exhibited with a urinary ratio of debrisoquine in relationship to its main 4-hydroxy metabolites ( ). In general, individuals are classified as poor metabolizers; intermediate, slow metabolizers; extensive metabolizers; or ultra-rapid metabolizers ( ). It is also interesting to note that the ability to metabolize, or the rate of metabolism of, CYP2D6 varies by race. For exam­ple, in the world, poor metabolization occurs in 0.5% to 2.4% of Asians, 3% to 7.3% of Whites, 3.3% of Mexican Americans, and 3.6% of Nicaraguans ( ). There are also a number of isoforms accounting for metabolism of specific classes of drugs such as CYP2C9, CYP2C10, and CYP3A4. The concept of understanding how race and drugs synergistically interact is termed ethnopharmacology. The following are examples of reactions to specific drugs.

Isoniazid is a drug commonly used to treat tuberculosis. People metabolize this drug in one of two ways: they inactivate it very slowly or very rapidly. Those who inactivate this drug very slowly are at risk for developing peripheral neuropathy during therapy ( ). Rapid inactivation of this drug occurs in 40% of Whites, 60% of African-Americans, 60% to 90% of American Indians and Eskimos, and 85% to 90% of Asians ( ; ). Pyridoxine is given with isoniazid, and the doses are spaced at larger intervals for slower reaction during treatment for tuberculosis. Primaquine is metabolized by oxidation and is used to treat malaria. When this drug is given to individuals who lack the enzymes necessary for glucose metabolism of the red blood cells, hemolysis of the red blood cells occurs. Approximately 100 million people in the world are affected by this particular enzyme deficiency and thus are unable to ingest primaquine. Approximately 35% of African-Americans have this particular enzyme deficiency.

Succinylcholine is a muscle relaxant used during surgery. It is inactivated by hydrolysis by the enzyme pseudocholinesterase. In most individuals it is rapidly inactivated, but some individuals have the atypical form of the enzyme and suffer prolonged muscle paralysis and an inability to breathe after administration of the drug. African-Americans, Asians, and American Indians are at risk for having pseudocholinesterase deficiency; Whites have a slightly higher risk than these groups. Some Jews and Alaskan Eskimos have a considerably greater risk: 1 of 135 Alaskan Eskimos cannot metabolize the drug succinylcholine normally ( ; ).

Alcohol is metabolized differently, depending on race. Two enzymes are involved in the metabolism of alcohol: alcohol dehydrogenase (ADH) and acetaldehyde dehydrogenase (ALDH). Alcohol metabolism is a two-step process: ADH converts alcohol to acetaldehyde, and acetaldehyde ALDH converts acetaldehyde (a toxic substance) to acetic acid (a nontoxic substance). Both of these enzymes have more than one variant. ADH has a high-activity type, which converts alcohol to acetaldehyde rapidly, and a low-activity variant, which converts it slowly ( ; ). ALDH has four variants (ALDH-1 through ALDH-4). ALDH-1 is considered “normal”; other types are less efficient in their ability to metabolize acetaldehyde ( ).

In Whites with “normal” levels of both ADH and ALDH-1, alcohol is metabolized fairly efficiently. In contrast, American Indians and Asians have an excessive level of high-activity ADH and a low level of ALDH-1. Consequently, persons in these groups metabolize alcohol to acetaldehyde rapidly. However, the metabolism to acetic acid is delayed. Because acetaldehyde is toxic and acetic acid is not, the net result is unpleasant effects, such as facial flushing and palpitations ( ; ). Data from some studies indicate that American Indians and Asians experience noticeable facial flushing and other vasomotor symptoms after ingesting alcohol; in contrast, Whites and African-Americans experience less severe reactions. Facial flushing after ingestion of alcohol occurs in 45% to 85% of Asians versus 3% to 29% of Whites ( ; ).

In regard to alcohol use, recent data suggest that Hispanic Americans and Black Americans are also at an increased risk for death from liver cirrhosis. Although the reasons for this remain largely unknown, one study compared racial and ethnic aspartate aminotransferase and gamma-glutamyltransferase level elevations among these individuals who drank ( ). Findings from this study suggest that among current drinkers, Black and Mexican Americans were more likely to have a twofold elevation of aspartate aminotransferase level than their White counterparts. These elevated levels were even more pronounced among those who drank more frequently (Mexican American: odds ratio, 9.1 [95% confidence interval, 3.9–21]; Black Americans: odds ratio, 3.1 [95% confidence interval, 1.4–6.8]) than among those who drank less frequently or were abstainers ( ).

Caffeine, a component of many drugs as well as coffee, tea, and colas, appears to be metabolized and excreted faster by Whites than by Asians ( ; ). It is thought that the differences noted in caffeine metabolism are directly correlated with liver enzyme differences ( ).

Antihypertensives are another category of drugs that are metabolized differently depending on race. Several studies suggest that there are notable differences between African-Americans and their White counterparts in the metabolism of antihypertensive drugs ( ; ; ; ). noted that African-Americans tend to need higher doses of beta-adrenergic receptor–blocking agents such as propranolol (Inderal). In contrast, angiotensin-converting enzyme inhibitors (such as captopril) tend to be less effective as a single therapy for African-Americans than for Whites with the same treatment regimen ( ; ; ). Given the plethora of information on African-Americans and their inability to efficiently metabolize some antihypertensive drugs adequately, there is a school of thought that suggests that these individuals must be treated aggressively with a combination of antihypertensive drugs (possibly three as a mean number). noted that even when African-Americans were prescribed an aggressive medication regimen, this did not necessarily correspond with satisfactory blood pressure control. It is also interesting to note that even when body surface area and body weight are considered, Chinese men tend to need only about half as much propranolol as White American men ( ; ; ).

Thiazide diuretics * are the drugs of choice for initial therapy in hypertension, but genes play a major role in sodium reabsorption and can affect a patient’s response to diuretic therapy. African-Americans’ response to anti­hypertensive therapy is associated with chromosome 12q15[30,31] where the FRS2 gene is located. This is involved in growth factor signaling. FRS2 plays a significant role in vascular smooth muscle cell regulation ( ). Patients with a single nucleotide polymorphism of the T594M gene (epithelial sodium channel) variant are thought to respond more favorably to amiloride therapy for blood pressure control than to thiazide-based diuretic drugs. In case of severe hypokalemia, potassium-sparing diuretics such as amiloride or triamterene should be used according to serum sodium and potassium levels ( ; ; ).

* This paragraph contributed by Henry Lewis, III, PharmD.

It is important for the nurse to remember that certain psychotropic drugs can cause higher blood levels in certain individuals by virtue of race (such as Asian Americans). It is essential to modify the dosage of these drugs based not only on body surface area and weight but also on racial considerations.

noted that clients from developing countries are routinely given smaller doses of antipsychotics (or neuroleptics) because some racial groups metabolize drugs more slowly and therefore experience a greater drug effect. For neuroleptic medications, these same variations by race are found in the United States.

In a prospective classic study of tardive dyskinesia, found that among psychiatric outpatients treated with neuroleptic medications, race was a probable factor for this iatrogenic movement disorder. The data indicated that non-White clients, 97% of whom were African-American, were about twice as likely to develop tardive dyskinesia as their White counterparts. To ensure the accuracy of the results, the researchers controlled for other demographic and clinical risk factors.

In a follow-up study, found that, compared with Whites, non-Whites were younger, less skilled, more likely to be unmarried, and more likely to have a diagnosis of schizophrenia. Non-Whites were also more likely to receive higher doses of neuroleptics, principally because they were frequently given more high-potency depot medications. Despite the control for known tardive dyskinesia factors, the estimated rate of tardive dyskinesia was nearly twice as high for non-Whites as for Whites. According to , none of the other demographic, clinical, psychosocial, or general health variables measured in the study appeared to explain the association between race and the propensity for tardive dyskinesia. The correlation between race as a biological marker and the development of tardive dyskinesia remains unclear ( ). Habits such as drinking and smoking are known to speed drug metabolism, and thus the fact that some Whites and African-Americans drink significantly more alcohol than some Asian Americans is an important consideration.

Some researchers ( ; ) contend that African-American clients are significantly misdiagnosed as psychotic. Because they are viewed as more violent, they receive more medication and spend more time in seclusion than Whites, Hispanics, or Asians ( ). The higher dose of medication prescribed for African-Americans may result more from staff perception than from a decision based on serum levels and careful observation ( ).

Gender is another cultural consideration that may have a profound effect on the metabolism of drugs. suggest that women have the potential for higher blood plasma levels of psychotropic drugs, especially when used with oral contraceptives. In addition, they note that women have greater efficacy of antipsychotic agents and a greater likelihood of adverse reactions, such as hypothyroidism and, in older women, tardive dyskinesia. Although plausible explanations for these differences have been offered, women have traditionally been excluded from clinical trials measuring the efficacy and metabolism of certain drugs.

Electrocardiographic Patterns

A common finding in African-Americans, particularly in African-American men, is the occurrence of inverted T waves in the precordial leads of the electrocardiogram. This aberration is a normal variant in the African-American population but would indicate a pathological condition if found in other racial groups, such as Whites.

Susceptibility to Disease

Another category of differences between racial groups is susceptibility to disease. The increased or decreased incidence of a particular disease may be genetically determined.

Glucose-6-Phosphate Dehydrogenase

Another enzyme-deficiency disorder that is more prevalent in certain racial or ethnic groups is G-6-PD deficiency. Although this disorder is more prevalent in certain groups, these groups may have different forms of the deficiency. reported that the type A variety, which moves rapidly on starch-gel electrophoresis, is found in 35% of African-Americans who have the deficiency. The slow-moving type B variety is found in 65% of Blacks who have the deficiency and in nearly all non-Blacks who have the deficiency. However, all forms affect males more than females because the genetic inheritance is carried on the X chromosome. The Cantonese Chinese disorder of G-6-PD has been found among the Chinese and the people of Southeast Asia. The incidence of the Cantonese Chinese form ranges from 2% to 5% ( ). Still another form of G-6-PD deficiency is the Mediterranean variety, which is the most clinically severe type. This form of G-6-PD deficiency affects up to 50% of male Greeks, Sardinians, and Sephardic Jews.

An enzyme constituent of the red blood cells, G-6-PD is involved in the hexose monophosphate pathway, which accounts for 10% of glucose metabolism of the red blood cells ( ). Under normal circumstances the proportion of glucose metabolized through this pathway may increase greatly if the cells are subjected to oxidants causing metabolic stress. The result is the formation of increased methemoglobin and degradation of Hb. In addition, certain medications tend to overwhelm the protective mechanism, especially when older red blood cells are involved, because of a decline in G-6-PD activity with the aging of these cells. Red blood cells with a genetically determined deficiency of G-6-PD are unable to withstand lesser oxidative stresses, and as a result a hemolytic process ensues that precipitates a significant anemia.

In the presence of certain conditions, G-6-PD–deficient red blood cells hemolyze, resulting in hemolytic anemia. Conditions that precipitate hemolytic anemia in susceptible persons include the administration of certain drugs, such as quinine, aspirin, phenacetin, chloramphenicol, probenecid, sulfonamides, and thiazide diuretics. The presence of infection and the ingestion of fava beans (also called “broad beans” or “horse beans”) are also linked to the precipitous onset of hemolytic anemia. The fava bean is a dietary staple in some of the Mediterranean countries, such as Greece, and those of northern Africa. Favism, a condition induced by ingestion of the fava bean, is one of the most severe forms of G-6-PD hemolysis ( ). In addition, G-6-PD deficiency has been related to an adaptive process that prevents malaria. The discerning nurse should assist the client in identifying substances that are likely to precipitate hemolytic episodes. In addition, the client should be taught to exercise caution to prevent serious infections. Until an exposure occurs, G-6-PD deficiency is a condition that remains asymptomatic. The nurse must understand that hemolytic episodes are the result of culturally related nutritional habits and geographical and environmental location.

Nutritional Preferences and Deficiencies

Another category of differences among cultural groups is nutritional preferences and deficiencies.

Nutritional Preferences.

Nutritional preferences include habits and patterns. When it comes to food choices, people are creatures of habit. The term habit connotes inflexibility, although people do change their habits for many reasons. The term food patterns is more descriptive of food choices. Many factors are associated with the formation of food patterns and preferences. Food patterns are developed during childhood as a result of family lifestyle and ethnic or cultural, social, religious, geographical, economic, and psychological components. All of these variables influence an individual’s attitudes, feelings, and beliefs about certain foods. However, the paramount factors that seem to determine food choices are cultural and ethnic in nature. Adults in a particular culture set the tone for cultural food patterns, which establish the foundation for a child’s lifelong eating customs regarding the timing of meals, the number of meals per day, foods acceptable for specific meals, methods of preparation, dislikes and likes, and table manners. Over time, children develop a sense of stability and security in regard to certain food patterns and attitudes.

indicated that people exhibit distinct patterns of consuming foods in different combinations or forms and that for the most part these patterns have remained constant. For example, many southern Americans would routinely choose grits as a food but would not routinely choose lentils. However, American diets have become more homogeneous because of many factors, including transportation, advertising, mobility, economic status, methods of production, and appreciation of other people’s cultural heritage ( ; ; ; ).

Some people, based on their culture, have not been traditionally known to make food choices solely on the basis of the nutritional and health values of food. For example, one of the most nutritious vegetables is broccoli; however, broccoli ranks twenty-first among vegetables consumed in the United States. On the other hand, the tomato, which is the most commonly eaten vegetable in the United States, ranks sixteenth as a source of vitamins and minerals ( ).

When people relocate, they carry established food habits to the new location, but these habits are retained only if the foods are available in the new location and are affordable. Foods in various cultures have different prestige or status. For example, beef and certain seafoods, such as lobster, are regarded as high-status foods among people in the United States. Hindus from India consider cows to be sacred and therefore do not eat beef. In seafaring countries, seafoods have no status value because they are common. Foods obtain their status rating from various factors, including religious beliefs, availability, cost, cultural values, and traditions, or because a highly respected individual has endorsed them. Even today, in many cultures men and their opinions regarding food preferences are more highly regarded than women and their opinions. In fact, in certain cultures men are so highly regarded that they are served meals first, before women and children. As a result of this practice, women and children may receive insufficient quantities and fewer varieties of food.

Food also has symbolic meaning, in some cultures, that has nothing to do with nutritional value. In these cultures eating becomes associated with sentiments and assumptions about oneself and the world. Food becomes symbolic to people not only because of religious connotations but also because it can be used as a reward. For example, a mother who gives a child candy or ice cream as a reward for good behavior may be reinforcing that food as a good food. On the other hand, a mother who serves a particular food (such as broccoli or cabbage) and says she is doing so because of bad behavior may be reinforcing that food as a bad food or punishment.

Food patterns and nutrition among African-Americans.

Food patterns among African-Americans are not significantly different from those of non–African-Americans living in the same geographical area. However, distinct differences do exist for African-Americans living and raised in the North as compared with those in the South. African-Americans, as a cultural group, are in the low socioeconomic groups, which may precipitate nutritional problems. As a result of nutritional deficiencies, African-Americans tend to have medical problems that are somewhat different from those of White Americans. As mentioned earlier, hypertension is a medical problem that is twice as great in African-Americans as in White Americans. Another medical problem, particularly in women, that has been linked to food patterns and selections is obesity. Soul foods, which are generally cooked for long periods and well-seasoned, may also contribute to many of the medical problems that African-Americans encounter. Soul foods, which have their roots in southern African-Americans who saw their preparation as economical, are listed in Table 7-1 .

TABLE 7-1

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