Exclusion and Inclusion of Nonwhite Ethnic Minority Groups in 72 North American and European Cardiovascular Cohort Studies: March 2006 - Volume 3

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Abstract

Background
Cohort studies are recommended for understanding ethnic disparities in cardiovascular disease. Our objective was to review the process for identifying, including, and excluding ethnic minority populations in published cardiovascular cohort studies in Europe and North America.

Methods and Findings
We found the literature using Medline (1966–2005), Embase (1980–2001), Cinahl, Web of Science, and citations from references; consultations with colleagues; Internet searches; and RB's personal files. A total of 72 studies were included, 39 starting after 1975. Decision-making on inclusion and exclusion of racial/ethnic groups, the conceptual basis of race/ethnicity, and methods of classification of racial/ethnic groups were rarely explicit. Few publications provided details on the racial/ethnic composition of the study setting or sample, and 39 gave no description. Several studies were located in small towns or in occupational settings, where ethnic minority populations are underrepresented. Studies on general populations usually had too few participants for analysis by race/ethnicity. Eight studies were explicitly on Caucasians/whites, and two excluded ethnic minority groups from the whole or part of the study on the basis of language or birthplace criteria. Ten studies were designed to compare white and nonwhite populations, while five studies focused on one nonwhite racial/ethnic group; all 15 of these were performed in the US.

Conclusions
There is a shortage of information from cardiovascular cohort studies on racial/ethnic minority populations, although this has recently changed in the US. There is, particularly in Europe, an inequity resulting from a lack of research data in nonwhite populations. Urgent action is now required in Europe to address this disparity.

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Introduction
Cardiovascular disease is the most common cause of death in most industrialised societies and is either the leading or a dominant cause of death for all racial and ethnic groups in the US and the UK. The risk is especially high amongst those originating from the Indian subcontinent—South Asians 1.

Research on ethnic group differences and similarities may potentially help advance understanding of the relationships between risk factors and cardiovascular disease. Cardiovascular cohort studies have been one of the key approaches for achieving such understanding 2,3. Most such studies started after World War II, when coronary heart disease mortality increased in many western countries 2. This period coincided with an expansion of migration from developing to industrialised countries, leading to a marked increase in ethnic diversity in Europe and North America in the late 20th century (http://www.migrationinformation.org/GlobalData/countrydata/data.cfm). The inclusion of minority groups in such cohort studies is important not only to compare differences in health status between groups but also to assess risk factor-outcome relationships within such groups. Levy 3 has called for cohort studies to seek answers to ethnic disparities in cardiovascular risks identified in cross-sectional work, while Bhopal and Senior have outlined the problems and potential of ethnicity as an epidemiological variable 4.

The main objective of this review was to identify how the major cardiovascular cohort studies in North America and Europe included or excluded ethnic minority populations. The methods and aims of this review could be extended, but these geographical areas were chosen because cardiovascular cohort studies have been pioneered by groups in these locations 2.

There is no clearly defined line between what is, and what is not, a cardiovascular cohort study, and individual judgment is required to make that determination. For the purposes of this review, cardiovascular cohort studies were defined as prospective studies in defined populations, with a primary aim of studying risk factor-outcome relationships for major diseases such as stroke and coronary heart disease. Studies included are summarised in Table S1 5-76.

Cohort studies with a multipurpose aim, those focused on other diseases, and those arising from studies originally designed as cross-sectional surveys or trials were generally excluded, as were studies of populations in which the investigators had little or no control over the sample (e.g., volunteers), although they may have yielded some cardiovascular data. A list of the studies that were given careful consideration but excluded, with reasons given, is in Table S2. Our reasoning for focusing on cardiovascular cohort studies, in addition to personal and academic interest, was this: Ethnic variations in cardiovascular disease give a clear rationale for inclusion of ethnic and racial minority groups, which may not be present for other conditions. This review may help health and research policy makers and the research community to judge whether there is equity, by which we mean needs of different population shave been met equally well, and, if not, whether we need new studies.

 

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References
  1. Gill PS, Kai J, Bhopal RS, Wild S (2002) Health care needs assessment: Black and minority ethnic groups. In: Raftery J, editor. The epidemiologically based needs assessment reviews. Third series. In press. Available at: http://hcna.radcliffe-oxford.com/bemgframe.htm. Accessed 29 November 2005.
  2. Prospective Studies Collaboration (1995) Cholesterol, diastolic blood pressure, and stroke: 13,000 strokes in 450,000 people in 45 prospective cohorts. Lancet 346: 1647–1653.
  3. Levy D, Kannel WB (2000) Searching for answers to ethnic disparities in cardiovascular risk. Lancet 356: 266–267.
  4. Senior PA, Bhopal RS (1994) Ethnicity as a variable in epidemiological research. BMJ 309: 327–330.
  5. Morris JN, Kagan A, Pattison DC (1996) Incidence and prediction of ischaemic heart disease in London busmen. Lancet 2: 553–559.
  6. Keys A (1980) Seven countries. A multivariate analysis of death and coronary heart disease. Cambridge (Massachusetts): Harvard University Press. 361 p.
  7. Kozarevic D, Pirc B, Dawber TR, Kahn HA, et al. (1971) Prevalence and incidence of coronary disease in a population study. The Yugoslavia Cardiovascular Disease Study. J Chronic Dis 24: 495–505.
  8. Kornitzer M, Dramaix M, Beriot I, Lannoy M, Gheyssens H, et al. (1993)Twenty-five-year mortality follow-up in the Belgian Bank Study. J Cardiol 82: 153–171.
  9. Reunanen A, Aromaa A, Pyvrdld K, Punsar S, Maatela J, et al. (1983) The Social Insurance Institution’s coronary heart disease study. Baseline dataand 5-year mortality experience. Acta Med Scand 673: 1–120.
  10. Jónsdóttir LS, Sigfusson N, Sigvaldason H, Thorgeirsson G (1998) Incidence and prevalence of recognised and unrecognised myocardial infarction in women. The Reykjavik Study. Eur Heart J 19: 1011–1018.
  11. Reid DD, Bert GZ, Hamilton PJS, Jarett KJ, Keen H, et al. (1974) Cardiorespiratory disease and diabetes among middle-aged male civil servants. Lancet 1: 469–473.
  12. Ducimetiere P, Richard J, Cambien F (1986) The pattern of subcutaneousfat distribution in middle-aged men and the risk of coronary heart disease:The Paris Prospective Study. Int J Obes 10: 229–240.
  13. Bengtsson C, Blohme G, Hallberg L, Hallstrom T, Issakson B, et al. (1973)The study of women in Gothenburg 1968–69—A population study. General design, purpose, and sampling results. Acta Med Scand 193: 311–318.
  14. Tomas-Abadal L, Varas-Lorenzo C, Bernades-Bernat E, Balaguer-Vintro I(1994) Coronary risk factors and a 20-year incidence of coronary heartdisease and mortality in a Mediterranean industrial population. The Manresa Study, Spain. Eur Heart J 15: 1028–1036.
  15. Gyntelberg F (1973) Screening for hypertension in an epidemiological study. Acta Med Scand 193: 393–397.
  16. Meade TW, North WRS, Chakrabarti R, Stirting Y (1980) Hemostatic function and cardiovascular death: Early results of a prospective study. Lancet 2: 533–537.17.
  17. Leren P, Askervold EM, Foss OP, Froli A, Grymyr D, et al. (1975) The Oslo Study. Cardiovascular disease in middle-aged and young Oslo men. Acta Med Scand 588: 1–38.
  18. Hawthorne VM, Watt GCM, Hart CC, Hole DJ (1995) Cardiorespiratory disease in men and women in urban Scotland: Baseline characteristics of the Renfrew/Paisley (MIDSPAN) study population. Scott Med J 40: 102–107.
  19. Vartiainen E, Sarti C, Tuomilehto J, Kuulasmaa K (1995) Do changes in cardiovascular risk factors explain changes in mortality from stroke in Finland? BMJ 310: 901–904.
  20. Bonaa KH, Arnesen E (1992) Association between heart rate and atherogenic blood lipid fractions in a population. The Tromso Study. Circulation 86: 394–405.
  21. Bjartveit K, Foss OP, Gjervig T, Lund-Larsen PG (1979) The cardiovascular disease study in Norwegian counties. Background and organisation. ActaMed Scand (Suppl) 634: 5–70.
  22. Law MR, Wald NJ, Wu T, Hackshaw A, Bailey A (1994) Systematic underestimation of association between serum cholesterol concentration and ischemic heart disease in observational studies: Data from the BUPA study. BMJ 308: 363–366.
  23. Rosolova H, Simon J, Sefrna F (1994) Impact of cardiovascular risk factors on morbidity and mortality in Czech middle-aged men: Pilsen Longitudinal Study. Cardiology 85: 61–68.
  24. Hansen AT, Schnohr P, Jensen G, Nyboe J, Appleyard M, et al. (1989) The Copenhagen City Heart Study. Osterbroundersogelsen. A book of tables with data from the first examination (1976–78) and a five-year follow up (1981–83). Scand J Soc Med 170: 11–180.
  25. De Maat MPM, Bladbjerg EM, Drivsholm T, Borch-Johnsen K, Moller L, et al. (2003) Inflammation, thrombosis and atherosclerosis: Results of the Glostrup Study. J Thromb Haemost 1: 950–957.
  26. Bakx JC, Veldstra MI, Van de Hoogen HJM, Zielhuis GA, Thien T, et al.(2001) Blood pressure and cardiovascular morbidity and mortality in a Dutch Population: The Nijmegen Cohort Study. Prev Med 32: 142–147.
  27. Kemper HCG, editor (1995) The Amsterdam Growth Study: A longitudinal analysis of health, fitness and lifestyle. Volume 6, HK Sport Science Monograph Series. Champaign (Illinois): Human Kinetics. 288 p.
  28. Shaper AG, Pocock SJ, Walker M, Cohen M, Wale CJ, et al. (1981) British Regional Heart Study: Cardiovascular risk factors in middle-aged men in 24 towns. BMJ 288: 179–186.
  29. Schulte H, Cullen P, Assmann G (1999) Obesity, mortality and cardiovascular disease in the Munster Heart Study (PROCAM). Atherosclerosis 144:199–209.
  30. De Backer G (1984) Regional differences in dietary habits, coronary risk factors and mortality rates in Belgium. I. Design and methodology. ActaCardiol 39: 285–292.
  31. Merlo J, Ranstram J, Liedholm H, Hedblad B, Lindberg G, et al. (1996)Incidence of myocardial infarction in elderly men being treated with antihypertensive drugs-population-based cohort study. BMJ 313: 457–461.
  32. Caerphilly and Speedwell Collaborative Group (1984) Caerphilly and Speedwell Collaborative Heart Disease Studies. J Epidemiol Community Health 38: 259–262.
  33. Puddu PE, Lanti M, Menotti A, Mancini M, Zanchetti A, et al. (2001) Serumuric acid for short-term prediction of CVD incidence in the Gubbio Population Study. Acta Cardiology 56: 243–251.
  34. Salonen JT, Tuomainen TP, Salonen R, Lakka TA, Nyysonen R (1998) Donation of blood is associated with reduced risk of myocardial infarction. Am J Epidemiol 148: 445–451.
  35. Marmot MG, Davey Smith G, Stansfield S, Patel C, North F, et al. (1991)Health inequalities among British civil servants: The Whitehall-II Study.Lancet 337: 1387–1393.
  36. Ducimetiere P, Guize L, Milon MH, Richard J, Rufat P, et al. (1995)Arteriographically documented coronary artery disease and alcohol consumption in French men: The CORALI Study. Eur Heart J 14: 727–733.
  37. Smith WC, Crombie IK, Tavendake R, Irving JM, Kenicer MB, et al. (1987)The Scottish Heart Health Study: Objectives and development of methods. Health Trends 45: 211–217.
  38. Beks PJ, Mackay AJC, de Neeling JND, de Vries H, Bouter LM, et al. (1995)Peripheral arterial disease in relation to glycaemic level in an elderly Caucasian population: The Hoorn Study. Diabetologia 38: 86–96.
  39. Houterman S, Verschuren WM, Hofman A, Witteman JC (1999) Serum cholesterol as a risk factor for myocardial infarction in elderly men and women: The Rotterdam Study. J Int Med 246: 25–33.
  40. Kiechl S, Willeit J, Egger G, Oberhollenzer M, Aichner F (1994) Alcohol consumption and carotid atherosclerosis: Evidence of dose-dependant atherogenic and antiatherogenic effects. Results from the Bruneck Study. Stroke 25: 1593–1598.
  41. Edinburgh Artery Study: Prevalence of asymptomatic and symptomatic peripheral arterial disease in the general population. Int J Epidemiol 20:384–391.
  42. Scarabin PY, Aillaid MF, Amouyel P, Evans A, Luc G, et al. (1998)Association of fibrinogen, factor 7 and PAI-1 with baseline findings among 10,500 male participants in a prospective study of myocardial infarction—The PRIME Study. Prospective Epidemiological Study of Myocardial Infarction. Thromb Haemost 80: 749–756.
  43. Simons PC, Algra A, van de Laak MF, Grobbee DE, van der Graaf (1999)Second Manifestations of ARTerial disease (SMART) Study: Rationale and design. Eur J Epidemiol 15: 773–781.
  44. Cremer P, Nagel D, Mann H, Labrot B, Muller-Berninger R, et al. (1997)Ten year follow-up results from the Goettingen Risk, Incidence and Prevalence Study (GRIPS). 1. Risk factors for myocardial infarction in a cohort of 5790 men. Atherosclerosis 129: 221–230.
  45. Lawlor DA, Taylor M, Bedford C, Ebrahim S. (2002) Is housework good for health? Levels of physical activity and factors associated with activity in elderly women. Results from the British Women’s Heart and Health Study. J Epidemiol Community Health 56: 473–478.
  46. Mathewson FA, Brereton CC, Keltie WA, Paul GI (1965) The University of Manitoba Follow-up study. A prospective investigation of cardiovascular disease. Can Med Assoc J 92: 947–953.
  47. Klag MJ, Ford DE, Mead LA, Jiang H, Whelton PK, et al. (1993) Serum cholesterol in young men and subsequent cardiovascular disease. N Engl J Med 328: 313–318.
  48. Dawber TR, Kannel WB, Lyell LP (1963) An approach to longitudinal studies in a community: The Framingham Study. Ann N Y Acad Sci 107:539–555.
  49. Paul O, Lepper MH, Phelan W (1963) A longitudinal study of coronary heart disease. Circulation 28: 20–31.
  50. Thomas J, Semenya KA, Neser WB, Thomas DJ, Green DR, et al. (1984)Precursors of hypertension in black medical students: The Meharry Cohort Study. J Natl Med Assoc 76: 111–112.
  51. Epstein FH, Ostrander LD Jr., Johnson BC, Payne MW, Hayner NS, et al.(1965) Epidemiological studies of cardiovascular disease in a total community—Tecumseh, Michigan. Ann Intern Med 62: 1170–1185.
  52. McDonough JR, Hames CG, Stulb SC, Garrison GE (1963) Cardiovascular disease field study in Evans County, Ga. Public Health Rep 78: 1051–1059.
  53. Keil JE, Loadholt CB, Weinrich C, Sandifer SH, Boyle E (1984) Incidence of coronary heart disease in blacks in Charleston, South Carolina. Am Heart J 108: 779–786.
  54. Sesso HD, Paffenbarger RS, Ha T, Lee I-M (1999) Physical activity and cardiovascular disease risk in middle-aged and older women. Am J Epidemiol 150: 408–415.
  55. Donahue RP Abbott RD, Reed D, Yano K (1988) Physical activity and coronary heart disease in middle-aged and elderly men: The Honolulu Heart program. Am J Public Health 78: 683–685.
  56. Stamler J, Dyer AR, Shekelle RB, Neaton J, Stamler R (1993) Relationship of baseline major risk factors to coronary and all-cause mortality, and to longevity: Findings from long-term follow-up of Chicago cohorts. Cardiology82: 191–222.
  57. He J, Ogden LG, Bazzano LA, Vupputuri S, Loria C, et al. (2001) Risk factors for congestive heart failure in US men and women: NHANES I epidemiologic follow-up study. Arch Intern Med 161: 996–1003.
  58. Lauer MR, Connor WE, Leaverton PE, Reiter MA (1975) Coronary heart disease risk factors in school: The Muscatine Study. J Pediatr 86: 697–706.
  59. Barrett-Connor E, Criqui MH, Klauber MR, Holdbrook M (1981) Diabetes and hypertension in a community of older adults. Am J Epidemiol 113:276–284.
  60. Croft JB, Webber LS, Parker FC, Berenson GS (1984) Recruitment and participation of children a long-term study of cardiovascular disease: The Bogalusa Heart Study, 1973–1982. Am J Epidemiol 120: 436–448.
  61. Beeson WL, Mills PK, Phillips RL, Andress M, Fraser GE (1989) Chronic disease among Seventh-day Adventists, a low-risk group. Rationale, methodology, and description of the population. Cancer 64: 570–581.
  62. Maskarinec G, Meng L, Kolonel LN (1998) Alcohol intake, body weight, and mortality in a multiethnic prospective cohort. Epidemiology 9: 654–661.
  63. Manson JE, Willett WC, Meir J, Stampfer MJ, Colditz GA, et al. (1995) Bodyweight and mortality among women. N Engl J Med 333: 677–685.
  64. Lee IM, Paffenbarger R Jr. (1998) Physical activity and stroke incidence: The Harvard Alumni Health Study. Stroke 29: 2049–2054.
  65. Howard VB, Davis PM, Pettitt DJ, Knowler WC, Bennett PH (1983) Plasma and lipoprotein cholesterol and triglyceride concentrations in the Pima Indians: Distributions differing from those of Caucasians. Circulation 68:714–724.
  66. Lee TE, Welty TR, Fabsitz R, Cowan LD, Le NA, et al. (1990) The Strong Heart Study. A study of cardiovascular disease in American Indians: Design and methods. Am J Epidemiol 132: 1141–1155.
  67. Friedman GD, Cutter GR, Donahue RP, Hughes GH, Hulley SB. et al. (1988)CARDIA: Study design and recruitment and some characteristics of the examined subjects. J Clin Epidemiol 41: 1105–1116.
  68. Stern MP, Rosenthal M, Haffner SM, Hazuda HP, Franco LJ (1984) Sexdifference in the effects of sociocultural status on diabetes and cardiovascular risk factors in Mexican Americans. The San Antonio Heart Study. Am J Epidemiol 120: 834–851.
  69. ARIC Investigators (1989) The Atherosclerosis Risk in Communities (ARIC)Study: Design and objectives. Am J Epidemiol 129: 687–702.
  70. French SA, Folsom AR, Jeffery RW, Williamson DR (1999) Prospective study of intentionality of weight loss and mortality in older women: The Iowa Women’s Health Study. Am J Epidemiol 149: 504–514.
  71. Rimm EB, Ascherio A, Giovannucci E, Spiegelman D, Stampfer, et al.(1996) Vegetable, fruit, and cereal fiber intake and risk of coronary heart disease among men. JAMA 275: 447–451.
  72. Fried LP, Borhani NO, Enright P, Furberg CD, Gardin JM, et al. (1991) The Cardiovascular Health Study: Design and rationale. Ann Epidemiol 1: 263–276.
  73. The Women’s Health Initiative Study Group (1997) Design of the women’s health initiative clinical trial and observational study. Controlled Clin Trials 19: 61–109.
  74. Dwyer JH, Navab M, Dwyer KM, Hassan K, Sun P, et al. (2001) Oxygenated carotenoid lutein and progression of early atherosclerosis: The Los Angeles atherosclerosis study. Circulation 103: 2922–2927.
  75. National Heart, Lung, and Blood Institute. Jackson Heart Study. Available:http://www.nhlbi.nih.gov/about/jackson/index.htm. Accessed 29 November2005.
  76. Bild DE, Bluemke DA, Burke GL, Detrano R, Diez Roux AV, et al. (2002)Multi-ethnic study of atherosclerosis: Objectives and design. Am J Epidemiol 156: 871–881.
  77. Day N, Oakes S, Luben R, Khaw KT, Bingham S, et al. (1999) EPIC-Norfolk: Study design and characteristics of the cohort. European Prospective Investigation of Cancer. Br J Cancer 80: 95–103.
  78. Pedoe HT, Clayton D, Morris JN, Brigden W, McDonald L (1975) Coronary heart-attack in East London. Lancet 2: 833–838.
  79. Wild S, McKeigue P (1997) Cross sectional analysis of mortality by country of birth. BMJ 314: 705–710.
  80. British Cardiac Society, British Hyperlipidaemia Association, British Hypertension Society, British Diabetic Association (2000) Joint British recommendations on prevention of coronary heart disease in clinical practice: Summary. BMJ 320: 705–707.
  81. Cappuccio FP, Oakeshott P, Strazzullo P, Kerry SM (2002) Application of Framingham risk estimates to ethnic minorities in United Kingdom and implications for primary prevention of heart disease in general practice: Cross sectional population based study. BMJ 325: 1–6.
  82. Feder G, Crook AM, Magee P, Banerjee S, Timmis AD, et al. (2002) Ethnic differences in invasive management of coronary disease: Prospective cohort study of patients undergoing angiography. BMJ 324: 511–516.
  83. Bhopal RS (1998) Spectre of racism in health and healthcare: Lessons from history and the United States. BMJ 316: 1970–1973.
  84. . Whitty CJ, Brunner EJ, Shipley MJ, Hemingway H, Marmot MG (1998) Differences in biological risk factors for cardiovascular disease between three ethnic groups in the Whitehall II study. Atherosclerosis 142: 279–286.
  85. Menotti A, Farchi G, Seccareccia F, RIFLE Research Group (1994) The prediction of coronary heart disease mortality as a function of major risk factors in over 30,000 men in the Italian RIFLE pooling project. A comparison with the MRFIT primary screenees. J Cardiovasc Risk 1: 263–270.
  86. McKeigue PM, Shah B, Marmot MG (1991) Relation of central obesity and insulin resistance with high diabetes prevalence and cardiovascular risk in South Asians. Lancet 337: 382–386.
  87. Bhopal RS, Unwin N, White M, Yallop J, Walker L, et al. (1999)Heterogeneity of coronary heart disease risk factors in Indian, Pakistani, Bangladeshi and European origin populations: cross sectional study. BMJ 319: 215–220.
  88. Sherwin R, Kaelber CT, Kezdi P, Kjelsberg MO, Thomas HE Jr. (1981) The Multiple Risk Factor Intervention Trial (MRFIT) II. The Development of the Protocol. Prev Med 10: 402–425.
  89. Chaturvedi N, McKeigue PM (1994) Methods of epidemiological surveys of ethnic minority groups. J Epidemiol Community Health 48: 107–111.
  90. Home Office (2001) Race Relations (Amendment) Act 2000. New laws for a successful multi-racial Britain. London: Home Office Communication Directorate. pp. 7–63.
  91. National Institutes of Health (2000) Strategic research plan to reduce and ultimately eliminate health disparities. Washington (DC): United States Department of Health and Human Services. 47 p. Available: http://www.nih.gov/about/hd/strategicplan.pdf. Accessed 29 November 2005.