Race and health
Race and health research has found many health differences between different races. In some cases, such as single gene disorders, the cause is clearly genetic, while in other cases environmental factors are likely involved to varying degrees.
- 1 Race differences regarding specific diseases
- 2 Causes of racial/ethnic disease differences
- 3 Other topics related to racial health differences
- 4 Controversy regarding use of race
- 5 See also
- 6 External links
- 7 References
Race differences regarding specific diseases
Single gene disorders
There are many single gene genetic disorders that differ in frequency between different populations. Some examples are discussed below.
Sickle-cell anemia is most prevalent in populations of Sub-Saharan African ancestry, but it is also exists in other populations afflicted by malaria. This is explained by the sickle-cell gene variant protecting against malaria. Several other genetic diseases are also more prevalent in these areas, such as thalassaemias.
Cystic fibrosis is the most common single gene disease in White populations. Several evolutionary explanations for the high frequency have been proposed, such as the gene variant increasing resistance against certain infectious diseases.
Hereditary hemochromatosis is most common among those of Northern European ancestry, in particular those of Celtic descendent. This may be due to evolutionarily low iron content in the food supply.
Lactose intolerance differ in frequency between populations. High lactose digestion capacity in adults is only common in populations of European and circum-Mediterranean origin. This is thought to reflect varying evolutionary adaptations to drinking milk from domestic livestock.
These are many diseases which are likely caused by several factors and which differ in frequency between different races. Both genetic and environmental factors may be important for such differences.
Just one example is a large number of different types of cancer, which differ in frequency between African Americans and Europeans in the US.
Another is racial differences regarding the frequency of sexually transmitted diseases.
Neurological and psychiatric diseases
Studies have also found ethnic/racial differences regarding neurological and psychiatric diseases. Examples include:
- Dementia and Alzheimer's disease.
- Parkinson's disease.
- Multiple sclerosis.
- Huntington's disease.
- Generalized anxiety disorder, Panic disorder, Social anxiety disorder, and Post-traumatic stress disorder.
- Somatization disorder and hypochondriasis.
- Chronic fatigue syndrome.
- Eating disorders.
- Problem gambling.
- Personality disorders.
Causes of racial/ethnic disease differences
In the case of single gene disorders, the disease differences between different races/ethnicities are clearly due to genetic differences.
For other diseases ("complex"/multifactorial diseases) both genetic and environmental factors may be important. An increasing number of recent studies have provided evidence for that genetic differences between races/ethnicities is an explanation for disease differences between races/ethnicities.
For example, a 2012 study argued that there are large genetic differences between different populations, which affect the genetic risk of type 2 diabetes. The highest risk is in Africa and the lowest is in East Asia. One explanation for this is different genetic adaptations to different historical nutritional patterns in different regions.
Such genetic differences may be may also have other effects beside influencing disease risk. For example, differences regarding prostate cancer may be related to sex hormone differences. Differences regarding skin cancer are likely related to skin color differences.
A 2015 review stated that "Race and ethnicity can contribute to interindividual differences in drug exposure and/or response, which may alter risk–benefit in certain populations. Approximately one-fifth of new drugs approved in the past 6 years demonstrated differences in exposure and/or response across racial/ethnic groups, translating to population-specific prescribing recommendations in a few cases. When data from diverse populations were lacking, additional postmarketing studies were recommended. In this review we highlight several cases where race/ethnicity was central to regulatory decision-making."
A 2013 study found different levels between Black and Whites of vitamin D-binding proteins and that most of this was explained by genetic factors. This could mean that the current tests for vitamin D deficiency often over-diagnose such deficiency in Blacks.
Racial admixture (interbreeding) can have an effect on relationships between race and race-linked disorders. Multiple sclerosis, for example, is typically associated with people of European descent, but possibly due to admixture, African Americans have elevated levels of the disorder relative to Africans.
A 2010 review listed a large number of genetic admixture studies on disease and health related variables.
A 2013 study found genetic differences regarding the immune system between different ethnicites. This may cause differences not just regarding the response to infectious diseases, but also regarding autoimmune diseases.
Though there are exceptions, the vast majority of successful matches for bone marrow transplants take place between donors and patients of the same racial/ethnic background. Mixed-race individuals often find it very difficult to find a suitable donor.
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 and death in HIV-infected patients. In different races the same haplotype may be associated with different effects due to such differing interactions.
Racial differences regarding dementia may be related to IQ differences.
Myopia (near-sightedness/short-sightedness) is associated with high IQ. There are several possible environmental explanations for this association, such that near work like reading causes myopia or that persons with myopia prefer activities like reading. Another possibility is a genetic explanation where the genes which affect the brain and brain structures at the same time may affect structures in the eye which causes myopia. One possibility is the genes affecting the growth of myelin, which is present in both the brain and the eye. Furthermore, it has been argued that populations that differ regarding the average IQ also differ regarding the prevalence of myopia.
There are differences in overall racial health as indicated by factors such as racial differences in life expectancy, even in the same country. This is often explained as entirely due to environmental factors, as well as being evidence of discrimination. Other explanations include the racial differences regarding race and intelligence, since there is also a relationship between health and intelligence.
A 2015 study stated that "Causes of the well-documented association between low levels of cognitive functioning and many adverse neuropsychiatric outcomes, poorer physical health and earlier death remain unknown. [...] These findings indicate that a substantial level of pleiotropy exists between cognitive abilities and many human mental and physical health disorders and traits and that it can be used to predict phenotypic variance across samples." 
Controversy regarding use of race
- Piel FB, Patil AP, Howes RE, Nyangiri OA, Gething PW, Williams TN et al. Global distribution of the sickle cell gene and geographical confirmation of the malaria hypothesis. Nat Commun. 2010;1;104. PMID: 21045822 http://www.nature.com/ncomms/journal/v1/n8/abs/ncomms1104.html
- Davies JC, Alton EW, Bush A; Cystic fibrosis. BMJ. 2007 Dec 15;335(7632):1255-9. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2137053/
- Discovering your "Celtic Connection" & Do you have the "Celtic Curse". American Hemochromatosis Society. http://www.americanhs.org/celtic.htm
- Myrianthopoulos NC, Aronson SM. Population dynamics of Tay-Sachs disease. I. Reproductive fitness and selection. Am J Hum Genet. 1966;18;(4)313-27. PMID: 5945951
- Holden C, Mace R. Phylogenetic analysis of the evolution of lactose digestion in adults. Hum Biol. 1997;69;(5)605-28. http://www.ncbi.nlm.nih.gov/pubmed/9299882
- Winkler CA, Nelson GW, Smith MW (2010) Admixture mapping comes of age. Annu Rev Genomics Hum Genet 11 ():65-89. http://dx.doi.org/10.1146/annurev-genom-082509-141523 http://pubmed.gov/20594047
- Race Differences in Rates of Venereal Disease https://www.amren.com/news/2017/11/race-differences-in-rates-of-venereal-disease-std-sti/
- National Research Council (US) Panel on Race, Ethnicity, and Health in Later Life; Anderson NB, Bulatao RA, Cohen B, editors. Critical Perspectives on Racial and Ethnic Differences in Health in Late Life. Washington (DC): National Academies Press (US); 2004. 4, Ethnic Differences in Dementia and Alzheimer's Disease. Available from: https://www.ncbi.nlm.nih.gov/books/NBK25535/
- Wright Willis A, Evanoff BA, Lian M, Criswell SR, Racette BA. Geographic and ethnic variation in Parkinson disease: a population-based study of US Medicare beneficiaries. Neuroepidemiology, 2010;34:143-151 https://www.ncbi.nlm.nih.gov/pubmed/20090375
- Cree BA, Khan O, Bourdette D, Goodin DS, Cohen JA, Marrie RA et al.. Clinical characteristics of African Americans vs Caucasian Americans with multiple sclerosis. Neurology. 2004;63;(11)2039-45. PMID: 15596747
- Walker FO (2007) Huntington's disease. Lancet 369 (9557):218-28. http://dx.doi.org/10.1016/S0140-6736(07)60111-1
- Messias EL, Chen CY, Eaton WW (2007) Epidemiology of schizophrenia: review of findings and myths. Psychiatr Clin North Am 30 (3):323-38. http://dx.doi.org/10.1016/j.psc.2007.04.007
- Woodward AT, Taylor RJ, Bullard KM, Aranda MP, Lincoln KD, Chatters LM (2012) Prevalence of lifetime DSM-IV affective disorders among older African Americans, Black Caribbeans, Latinos, Asians and non-Hispanic White people. Int J Geriatr Psychiatry 27 (8):816-27. https://www.ncbi.nlm.nih.gov/pubmed/21987438
- Asnaani A, Richey JA, Dimaite R, Hinton DE, Hofmann SG (2010) A cross-ethnic comparison of lifetime prevalence rates of anxiety disorders. J Nerv Ment Dis 198 (8):551-5. http://dx.doi.org/10.1097/NMD.0b013e3181ea169f https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2931265/
- Creed F, Barsky A (2004) A systematic review of the epidemiology of somatisation disorder and hypochondriasis. J Psychosom Res 56 (4):391-408. http://dx.doi.org/10.1016/S0022-3999(03)00622-6 https://www.ncbi.nlm.nih.gov/pubmed/15094023
- Dinos S, Khoshaba B, Ashby D, White PD, Nazroo J, Wessely S et al. (2009) A systematic review of chronic fatigue, its syndromes and ethnicity: prevalence, severity, co-morbidity and coping. Int J Epidemiol 38 (6):1554-70. http://dx.doi.org/10.1093/ije/dyp147
- Brown, Melanie; Cachelin, Fary M.; Dohm, Faith-Anne. Eating Disorders in Ethnic Minority Women: A Review of the Emerging Literature Current Psychiatry Reviews, Volume 5, Number 3, August 2009 , pp. 182-193(12). http://www.ingentaconnect.com/content/ben/cpsr/2009/00000005/00000003/art00005
- Alegria AA, Petry NM, Hasin DS, Liu SM, Grant BF, Blanco C (2009) Disordered gambling among racial and ethnic groups in the US: results from the national epidemiologic survey on alcohol and related conditions. CNS Spectr 14 (3):132-42. http://pubmed.gov/19407710
- Mike J. Crawford, Tendai Rushwaya, Priya Bajaj, Peter Tyrer, Min Yang. The prevalence of personality disorder among ethnic minorities: findings from a national household survey. Personality and Mental Health. Volume 6, Issue 3, pages 175–182, August 2012 http://onlinelibrary.wiley.com/doi/10.1002/pmh.1186/abstract
- Chen R, Corona E, Sikora M, Dudley JT, Morgan AA, et al. (2012) Type 2 Diabetes Risk Alleles Demonstrate Extreme Directional Differentiation among Human Populations, Compared to Other Diseases. PLoS Genet 8(4): e1002621. doi:10.1371/journal.pgen.1002621 http://www.plosgenetics.org/article/info%3Adoi%2F10.1371%2Fjournal.pgen.1002621
- Ramamoorthy, A., Pacanowski, M. A., Bull, J., & Zhang, L. (2015). Racial/ethnic differences in drug disposition and response: review of recently approved drugs. Clinical Pharmacology & Therapeutics, 97(3), 263-273. http://onlinelibrary.wiley.com/doi/10.1002/cpt.61/full
- Powe CE, Evans MK, Wenger J, Zonderman AB, Berg AH, Nalls M et al. (2013) Vitamin D-binding protein and vitamin D status of black Americans and white Americans. N Engl J Med 369 (21):1991-2000. http://dx.doi.org/10.1056/NEJMoa1306357 http://pubmed.gov/24256378
- Benefits of Exercise Differ by Sex and Race. American Renaissance. http://www.amren.com/news/2009/09/benefits_of_exe/
- Exercise Benefits Black Girls Less than Whites, Study Shows. American Renaissance. http://www.amren.com/news/2012/06/exercise-benefits-black-girls-less-than-whites-study-shows/
- Exercise’s Anti-Cancer Benefits Vary by Race. American Reniassance. http://www.amren.com/news/2013/02/exercises-anti-cancer-benefits-vary-by-race/
- Gower, B. A. et al. "Using genetic admixture to explain racial differences in insulin-related phenotypes," Diabetes 52, 1047-1051 (2003).
- Fernandez, J. R. et al. "Association of African genetic admixture with resting metabolic rate and obesity among women," Obes. Res. 11, 904-911 (2003)
- Watson CT, Steinberg KM, Huddleston J, Warren RL, Malig M, Schein J et al. (2013) Complete haplotype sequence of the human immunoglobulin heavy-chain variable, diversity, and joining genes and characterization of allelic and copy-number variation. Am J Hum Genet 92 (4):530-46. http://dx.doi.org/10.1016/j.ajhg.2013.03.004 DOI:10.1016/j.ajhg.2013.03.004 http://pubmed.gov/23541343
- Bone Marrow Transplants: When Race Is an Issue. Thursday, June 03, 2010. Time. http://content.time.com/time/health/article/0,8599,1993074,00.html?artId=1993074?contType=article?chn=sciHealth
- Gonzalez, E. et al. Race-specific HIV-1 disease-modifying effects associated with CCR5 haplotypes. Proc. Natl Acad. Sci. USA. 96, 12004-12009 (1999). http://www.pnas.org/content/96/21/12004.short
- Czepita D, Lodygowska E, Czepita M (2008). "Are children with myopia more intelligent? A literature review". Annales Academiae Medicae Stetinensis 54 (1): 13–16; discussion 16. https://www.ncbi.nlm.nih.gov/pubmed/19127804
- Rushton, J. Philippe; Jensen, Arthur R. Thirty years of research on race differences in cognitive ability. Psychology, Public Policy, and Law, Vol 11(2), Jun 2005, 235-294. http://dx.doi.org/10.1037/1076-89220.127.116.11 http://psychology.uwo.ca/faculty/rushtonpdfs/PPPL1.pdf
- Hagenaars, Saskia P., et al. "Shared genetic aetiology between cognitive functions and physical and mental health in UK Biobank (N= 112 151) and 24 GWAS consortia." bioRxiv (2015): 031120. http://www.nature.com/mp/journal/vaop/ncurrent/full/mp2015225a.html