(Stroke. 2000;31:1013.)
© 2000 American Heart Association, Inc.
Editorial |
Ethnicity and Stroke
Beware of the Fallacies
From the Departments of Neurology, University of Buenos Aires, Buenos Aires, Argentina (O.F.), and Indiana University School of Medicine, Indianapolis, Ind (J.B.).
Correspondence to Osvaldo Fustinoni, MD, Institutos Médicos Antártida, Unidad de Ataque Cerebral, Rivadavia 4978, C1424CER Buenos Aires, Argentina. E-mail osvaldof{at}sminter.com.ar
Key Words: epidemiology • ethnic groups • stroke
The role of ethnicity in stroke has been the subject of a considerable number of published reports. A quick Medline search detected 454 citations on "ethnicity and stroke," 386 on "stroke in blacks," 251 on "stroke in African Americans," and 74 on "stroke in Hispanics," of which only a few can be mentioned here.1 2 3 4 5 6 7 8 9 10 11 12 There even exists a journal dedicated to ethnicity and health.13
However, the assumption that ethnicity is an isolated epidemiological variable delineating clinically distinct disease subgroups is controversial.14 15 16 17 The very concept of the word may be confounded with race ("black"), a common language or culture ("Hispanic"), a shared geographic origin ("Asian"), or a presumed common descent with diffuse boundaries ("Caucasian"). Ethnic categories are usually not defined in scientific reports, which results in dubious findings that are difficult to compare.18 The idea that a socially defined variable may reveal biological differences is fallacious, leading dangerously to biological determinism.15 For example, the genetic variation between races, traditionally classified on phenotype, is only slightly greater (10%) than that between nations (6%), and much larger within a local population (84%).18 19 Moreover, the genes responsible for skin color are few and are not associated with genetic markers for disease.14
Ethnicity as a variable may be too greatly influenced by cultural attitude and therefore biased. In the past, this attitude led to the entire invention of diseases on the basis of race. At a time when the genetic inequality of races was considered obvious, the existence of these diseases was not questioned.15 In the present, ethnicity may be used euphemistically to avoid racist implications. A survey of 48 medical schools in the United States revealed that up to 91% of clerkship directors answered "yes" or "variable" after being queried whether students were taught by example to use the terms "black" or "white" when introducing case presentations.20 In another study, "black" patients were far more likely than "whites" to be racially identified at morning report.21 As recently as 1991, arterial hypertension has been related to skin color, even allowing for the fact that darker "blacks" may as a consequence be poorer and suffer more psychosocial stress.22
Ethnic classification may vary from one community to another, as the perception of an ethnic group may be different across countries. As Caldwell and Popenoe20 put it, "what is black to someone from the United States may be white to a Brazilian or a Caribbean islander." It may be added that the authors of the present editorial, both of European descent and born and raised in Spanish-speaking countries, would probably be classified as "Hispanic" in the US, although neither is of Spanish descent. Obviously, there is no such thing as a "Hispanic" ethnic group in Spain or Latin America.
Ethnicity is not a dichotomous variable, such as gender. How black is black? How is a person classified whose father is "white" and mother "black"? What about "mixed" grandparents? How does one classify a phenotypically "black" (by US standards) Spanish-speaking national from Central America? How are his children classified? Finally, how white is white? Do a Scot from Edinburgh and an Italian from Milan belong to the same ethnic group?17
Ethnicity has been shown to vary through time. One study23 showed an increase in nonwhite races on death records compared with birth records in the same population and indicated that this reclassification may have been politically biased. A study on infant mortality24 showed that 87.3% of infants were ethnically reclassified at death, with the greatest inconsistency involving "Hispanics" (30.3%) and the least "whites" (1.2%).
To avoid the shortcomings linked to classification, it has been proposed (and is now used in many reports) that patients entering population studies "self-classify" their ethnicity,25 assuming that "racial and ethnic categories are understood by the populations questioned."26
However, misinterpretation, confusion, and self-reclassification have been found in these cases.26 27 One striking example is that the category "South and Central American" was thought by respondents in one census to refer to natives of the south and central United States!26
To define disease on the basis of biologically determined ethnicity might perhaps hide socioeconomic differences that are the real cause of disease in some ethnic groups. Affluent "blacks" from the US East Coast may not necessarily develop the same disease patterns as poor inhabitants from a comparable group in the southern states. Many reports on interethnic differences are not adjusted for socioeconomic variables, and this is perhaps the more important bias involving ethnicity research.
Senior and Bhopal14 have proposed that a "sound epidemiological variable" should be accurately measured and should differentiate populations by some underlying characteristic relevant to health (such as income, childhood circumstances, hormonal status, genetic inheritance, and lifestyle). The observed differences in patterns of disease should generate testable etiologic hypotheses or be applicable to the planning and delivery of health care. However, these observed differences have rarely led to applicable hypotheses beyond the initial observation, as researchers have emphasized the understanding of etiology rather than the development of specific health policies.
Because ethnicity is difficult to define, it is consequently difficult to measure. Ethnic populations are more and more heterogeneous, and ethnic heterogeneity is often underestimated. An example are the well-conducted studies of coronary heart disease and stroke in "Japanese" men living in Japan and in "Japanese-American" men from Hawaii and California (the Ni-Hon-San studies), which showed a gradient from high stroke rates in Japan to low rates in California and a reverse trend for coronary heart disease.28 29 30 More than 11 000 men were included. These theoretically conflicting trends could not be explained only by conventional risk factors31 or blood pressure distributions,32 "although the subjects shared a common ethnic background."33 It is very probable that ethnic heterogeneity is as important a confounder to the findings as environmental, dietary, and various other factors. The highly intriguing results of such studies, rather than being dismissed, merit a more rigorous approach.
Genetic research may be one way of achieving this. For instance, in the late eighties, familial cavernous malformations were reported to be more common among "Hispanics."34 35 However, more precise research showed linkage of these cavernous malformations to chromosome 7q11–22 in 4 unrelated Mexican families that might share a common ancestor in Sonora County, Mexico.36 We now also know that "white"37 and "Italian-American"38 families with cavernous malformations may show the same or other linkages, for example, to chromosomes 7p13–15 and 3q25.2–27.39 40 Of course, the familial occurrence points to an autosomal dominant inheritance and a highly probable genetic linkage, but all the same, this is an example of how a bit more precision can help us avoid inappropriate, incorrect, or even suspect generalizations.
The consequences of flawed ethnicity research may lead to the assumption that ethnic minorities are an unhealthy social burden, that there are "ethnic" diseases which separate specific groups from the general population, that consequently they do not merit any further attention, and that "whites" are the "gold standard" of health. All this could do nothing but fuel racial prejudice.15
Patterns of disease that distinguish different ethnic groups may well exist and should be adequately established if better health standards for the populations concerned can be achieved as a consequence. Failure to do so may just be an example of "black box epidemiology," resulting in futile and never-ending reports on interethnic differences that have been likened to repeatedly punching a soft pillow.41
Footnotes
The opinions expressed in this editorial are not necessarily those of the editors or of the American Heart Association.
References
1.
Mast H, Thompson JL, Lin IF, Hofmeister C,
Hartmann A, Marx P, Mohr JP, Sacco RL. Cigarette smoking as a
determinant of high-grade carotid artery stenosis in Hispanic,
black, and white patients with stroke or transient ischemic
attack. Stroke. 1998;29:908–912.
2.
Wong KS, Huang YN, Gao S, Lam WW, Chan YL, Kay R.
Intracranial stenosis in Chinese patients with acute stroke.
Neurology. 1998;50:812–813.
3. Rigdon EE. Racial and gender differences in outcome after carotid endarterectomy. Am Surg. 1998;64:527–530.[Medline] [Order article via Infotrieve]
4.
Massing MW, Rywik SL, Jasinski B, Manolio TA, Williams
OD, Tyroler HA. Opposing mortality trends in Poland and for African
Americans and whites in the United States, 1968 to 1994.
Stroke. 1998;29:1366–1372.
5.
Frey JL, Jahnke HK, Bulfinch EW. Differences in stroke
between white, Hispanic, and Native American patients: the Barrow
Neurological Institute database. Stroke. 1998;29:29–33.
6.
Sacco RL, Boden-Albala B, Gan R, Chen X, Kargman DE,
Shea S, Paik MC, Hauser WA. Stroke incidence among white, black, and
Hispanic residents of an urban community. Am J
Epidemiol. 1998;147:259–268.
7.
Broderick J, Brott T, Kothari R, Miller R, Khoury J,
Pancioli A, Gebel J, Mills L, Shukla R. The Greater Cincinnati/Northern
Kentucky Stroke Study: preliminary first-ever and total incidence rates
of stroke among blacks. Stroke. 1998;29:415–421.
8.
Gorelick PB. Cerebrovascular disease in African
Americans. Stroke. 1998;29:2656–64.
9.
Menon SC, Pandey DK, Morgenstern LB. Critical factors
determining access to acute stroke care. Neurology. 1998;51:427–432.
10.
Zeigler-Johnson CM, Holmes JL, Lassila HC,
Sutton-Tyrrell K, Kuller LH. Subclinical
atherosclerosis in relation to hysterectomy status in
black women. Stroke. 1998;29:759–764.
11. Mendelson G, Aronow WS, Ahn C. Prevalence of coronary artery disease, atherothrombotic brain infarction, and peripheral arterial disease: associated risk factors in older Hispanics in an academic hospital-based geriatrics practice. J Am Geriatr Soc. 1998;46:481–483.[Medline] [Order article via Infotrieve]
12. Sheinart KF, Tuhrim S, Horowitz DR, Weinberger J, Goldman M, Godbold JH. Stroke recurrence is more frequent in Blacks and Hispanics. Neuroepidemiology. 1998;17:188–198.[Medline] [Order article via Infotrieve]
13. Vos T, Gareeboo H, Roussety F. Ethnic differences in ischaemic heart disease and stroke mortality in Mauritius between 1989 and 1994. Ethn Health. 1998;3:45–54.[Medline] [Order article via Infotrieve]
14.
Senior PA, Bhopal R. Ethnicity as a variable in
epidemiological research. BMJ. 1994;309:327–330.
15.
Bhopal R. Is research into ethnicity and health racist,
unsound or important science? BMJ. 1997;314:1751–1756.
16.
Witzig R. The medicalization of race: scientific
legitimization of a flawed social construct. Ann Intern Med. 1996;125:675–679.
17.
Osborne NG, Feit MD. The use of race in medical
research. JAMA. 1992;267:275–279.
18.
McKenzie KJ, Crowcroft N. Race, ethnicity, culture, and
science. BMJ. 1994;309:286–287.
19. Jones JS. How different are human races? Nature.. 1981;293:188–190.[Medline] [Order article via Infotrieve]
20.
Caldwell SH, Popenoe R. Perceptions and misperceptions
of skin color. Ann Intern Med. 1995;122:614–617.
21. Finucane TE, Carrese JA. Racial bias in presentation of cases. J Gen Intern Med. 1990;5:120–121.[Medline] [Order article via Infotrieve]
22.
Klag MJ, Whelton PK, Coresh J, Grim CE, Kuller LH. The
association of skin color with blood pressure in US blacks with low
socioeconomic status. JAMA. 1991;265:599–602.
23.
Frost F, Shy KK. Racial differences between linked
birth and infant death records in Washington State. Am J
Public Health. 1980;70:974–976.
24.
Hahn RA, Mulinare J, Teutsch SM. Inconsistencies in
coding of race and ethnicity between birth and death in US infants: a
new look at infant mortality, 1983 through 1985. JAMA. 1992;267:259–263.
25.
Ethnicity, race, and culture: guidelines for research,
audit, and publication. BMJ. 1996;312:1094.
26.
Hahn RA. The state of federal health statistics on
racial and ethnic groups. JAMA. 1992;267:268–271.
27.
McAuley J, De Souza L, Robinson I, Main C, Frank AO.
Self defined ethnicity is unhelpful. BMJ. 1996;313:425.
Letter.
28.
Syme SL, Marmot MG, Kagan A, Kato H, Rhoads G.
Epidemiologic studies of coronary heart disease and stroke in
Japanese men living in Japan, Hawaii and California: introduction.
Am J Epidemiol.. 1975;102:477–480.
29. Robertson TL, Kato H, Rhoads GG, Kagan A, Marmot M, Syme SL, Gordon T, Worth RM, Belsky JL, Dock DS, Miyanishi M, Kawamoto S. Epidemiologic studies of coronary heart disease and stroke in Japanese men living in Japan, Hawaii and California: incidence of myocardial infarction and death from coronary heart disease. Am J Cardiol.. 1977;39:239–243.[Medline] [Order article via Infotrieve]
30.
Takeya Y, Popper JS, Shimizu Y, Kato H, Rhoads GG,
Kagan A. Epidemiologic studies of coronary heart disease and
stroke in Japanese men living in Japan, Hawaii and California:
incidence of stroke in Japan and Hawaii. Stroke. 1984;15:15–23.
31.
Marmot MG, Syme SL, Kagan A, Kato H, Cohen JB, Belsky
J. Epidemiologic studies of coronary heart disease and stroke
in Japanese men living in Japan, Hawaii and California: prevalence of
coronary and hypertensive heart disease and associated risk
factors. Am J Epidemiol. 1975;102:514–525.
32.
Winkelstein W Jr, Kagan A, Kato H, Sacks ST.
Epidemiologic studies of coronary heart disease and stroke in
Japanese men living in Japan, Hawaii and California: blood pressure
distributions. Am J Epidemiol. 1975;102:502–513.
33. Benfante R. Studies of cardiovascular disease and cause-specific mortality trends in Japanese-American men living in Hawaii and risk factor comparisons with other Japanese populations in the Pacific region: a review. Hum Biol. 1992;64:791–805.[Medline] [Order article via Infotrieve]
34.
Mason I, Aase JM, Orrison WW, Wicks JD, Seigel RS,
Bicknell JM. Familial cavernous angiomas of the brain in an Hispanic
family. Neurology. 1988;38:324–326.
35. Bicknell JM. Familial cavernous angioma of the brain stem dominantly inherited in Hispanics. Neurosurgery. 1989;24:102–105.[Medline] [Order article via Infotrieve]
36.
Polymeropoulos MH, Hurko O, Hsu F, Rubenstein J, Basnet
S, Lane K, Dietz H, Spetzler RF, Rigamonti D. Linkage of the locus for
cerebral cavernous angiomas to human chromosome 7q in four families of
Mexican-American descent. Neurology. 1997;48:752–757.
37. Gil-Nagel A, Dubovsky J, Wilcox KJ, Stewart JM, Anderson VE, Leppik IE, Orr HT, Johnson EW, Weber JL, Rich SS. Familial cerebral cavernous angioma: a gene localized to a 15-cM interval on chromosome 7q. Ann Neurol. 1996;39:807–810.[Medline] [Order article via Infotrieve]
38. Marchuk DA, Gallione CJ, Morrison LA, Clericuzio CL, Hart BL, Kosofsky BE, Louis DN, Gusella JF, Davis LE, Prenger VL. A locus for cerebral cavernous malformations maps to chromosome 7q in two families. Genomics. 1995;28:311–314.[Medline] [Order article via Infotrieve]
39. Gunel M, Awad IA, Finberg K, Steinberg GK, Craig HD, Cepeda O, Nelson-Williams C, Lifton RP. Genetic heterogeneity of inherited cerebral cavernous malformation. Neurosurgery. 1996;38:1265–1271.[Medline] [Order article via Infotrieve]
40.
Craig HD, Gunel M, Cepeda O, Johnson EW, Ptacek L,
Steinberg GK, Ogilvy CS, Berg MJ Crawford SC, Scott RM,
Steichen-Gersdorf E, Sabroe R, Kennedy CTC, Mettler G, Beis MJ, Fryer
A, Awad IA, Lifton RP. Multilocus linkage identifies two new loci for a
mendelian form of stroke, cerebral cavernous malformation, at 7p15–13
and 3q25.2–27. Hum Mol Genet.. 1998;7:1851–1858.
41. Skrabanek P: The emptiness of the black box. Epidemiology. 1994;5:553–555.[Medline] [Order article via Infotrieve]
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