Current Cardiovascular Risk Reports

, Volume 5, Issue 3, pp 200–206

Dissociation Between Cardiovascular Risk Markers and Clinical Outcomes in African Americans: Need for Greater Mechanistic Insight

Article

Abstract

Despite having distinct advantages, such as lower serum triglycerides, higher high-density lipoprotein (HDL) cholesterol levels, and less visceral adiposity, African Americans suffer disproportionately from cardiovascular disease (CVD). In African Americans, attention often focuses on two cardiometabolic risk factors—hypertension and type 2 diabetes mellitus—because they occur more frequently in African Americans than whites. Exactly how hypertension and hyperglycemia appear to override benefits from the lower prevalence of dyslipidemia and other factors is unknown. From a practical viewpoint, as the combined effects of hypertension and type 2 diabetes mellitus are dominant, then primary prevention with vigorous control of these conditions must be of utmost priority. However, because attention is focused on hypertension and type 2 diabetes mellitus, the role of other potential risk factors, such as low-density lipoprotein cholesterol oxidation, HDL cholesterol function, lipoxygenase pathway, endothelial progenitor cells, and natriuretic peptide regulation, have not been well studied. In this review, we discuss the paradox of CVD morbidity and mortality among African Americans and offer suggestions for future investigation.

Keywords

Cardiometabolic risk Ethnic disparities Novel mechanisms Genetic targets 

References

Papers of particular interest, published recently, have been highlighted as: •Of importance ••Of major importance

  1. 1.
    Centers for Disease Control and Prevention. Heart Disease Facts. http://www.cdc.gov/heartdisease/facts.htm
  2. 2.
    Lloyd-Jones D, Adams RJ, Brown TM, et al. Heart disease and stroke statistics 2010 update: a report from the American Heart Association. Circulation. 2010;121:e46–e215.PubMedCrossRefGoogle Scholar
  3. 3.
    Yusuf S, Hawken S, Ounpuu S, et al. Effect of potentially modifiable risk factors associated with myocardial infarction in 52 countries (the INTERHEART study): a case control study. Lancet. 2004;364:937–52.PubMedCrossRefGoogle Scholar
  4. 4.
    Nathan DM, Cleary PA, Backlund MS, et al. Intensive diabetes treatment and cardiovascular disease in patients with type 1 diabetes mellitus: DCCT/EDIC. NEJM. 2005;353:2643–53.PubMedCrossRefGoogle Scholar
  5. 5.
    Gaede P, Lund-Andersen H, Parving HH, Pedersen O. Effect of multifactorial intervention on mortality in type 2 diabetes. NEJM. 2008;358:580–91.PubMedCrossRefGoogle Scholar
  6. 6.
    Dagogo-Jack S. Ethnic disparities in type 2 diabetes: Pathophysiology and implications for prevention and management. J Natl Med Assoc. 2003;95:774–89.PubMedGoogle Scholar
  7. 7.
    Hurley LP, Dickinson LM, Estacio RO, et al. Prediction of cardiovascular death in racial/ethnic minorities using Framingham risk factors. Circ Cardiovasc Qual Outcomes. 2010;3:181–7.PubMedCrossRefGoogle Scholar
  8. 8.
    Mensah GA, Mokdad AH, Ford ES, et al. State of disparities in cardiovascular health in the United States. Circulation. 2005;111:1233–41.PubMedCrossRefGoogle Scholar
  9. 9.
    Kurian AK, Cardarelli KM. Racial and ethnic differences in cardiovascular disease risk factors: a systematic review. Ethn Dis. 2007;17:143–52.PubMedGoogle Scholar
  10. 10.
    Harris MI. Non-insulin dependent diabetes mellitus in black and white Americans. Diabetes Metab Rev. 1990;6:71–90.PubMedCrossRefGoogle Scholar
  11. 11.
    Ford ES, Giles WH, Dietz W. Prevalence of the metabolic syndrome among US adults, findings from the Third National Health and Nutrition Examination Survey. JAMA. 2002;287:356–9.PubMedCrossRefGoogle Scholar
  12. 12.
    •• Sumner AE, Cowie CC. Ethnic differences in ability of triglyceride levels to identify insulin resistance. Atherosclerosis. 2008;196:696–703. Using the NHANES 1999-2002 database, the authors found lower triglyceride levels and a lower prevalence of MetS in non-Hispanic blacks than Hispanics and non-Hispanic whites, underscoring the importance of ethnic differences in triglycerides.PubMedCrossRefGoogle Scholar
  13. 13.
    Chen W, Bao W, Begum S, Elkasabany A, Srinivasan SR. Berenson GS: age-related patterns of the clustering of cardiovascular risk variables of syndrome X from childhood to young adulthood in a population made up of black and white subjects, The Bogalusa Heart Study. Diabetes. 2000;49:1042–8.PubMedCrossRefGoogle Scholar
  14. 14.
    •• Katzmarzyk PT, Bray GA, Greenway FL, et al. Racial differences in abdominal depot-specific adiposity in white and African-American adults. Am J Clin Nutr. 2010;91:7–15. This report documents lower intraabdominal fat in African Americans compared with whites. After adjustment for covariates, African American men and women had lower visceral adipose tissue than white men and women. The situation is reversed with regard to subcutaneous fat, which was lower in whites, indicating marked ethnic heterogeneity in fat distribution.PubMedCrossRefGoogle Scholar
  15. 15.
    Lovejoy JC, de la Bretonne JA, Klemperer M, Tulley R. Abdominal fat distribution and metabolic risk factors: effects of race. Metabolism. 1996;45:1119–24.PubMedCrossRefGoogle Scholar
  16. 16.
    • Centers for Disease Control and Prevention. Cigarette Smoking Among Adults and Trends in Smoking Cessation—United States, 2008. Morbidity and Mortality Weekly Report. 2009;58(44):1227–32. This national report shows roughly similar cigarette smoking rates in whites and blacks, indicating that differences in smoking do not explain ethnic disparity in CVD.Google Scholar
  17. 17.
    Galassi A, Reynolds K, He J. Metabolic syndrome and risk of cardiovascular disease: a meta-analysis. American Journal of Medicine. 2006;119:812–9.PubMedCrossRefGoogle Scholar
  18. 18.
    Summer AE. Ethnic differences in triglyceride levels and high-density lipoprotein lead to underdiagnosis of the metabolic syndrome in black children and adults. J Pediatr. 2009;155:e7–e11.CrossRefGoogle Scholar
  19. 19.
    Carroll MD, Lacher DA, Sorlie PD, et al. Trends in serum lipids and lipoproteins of adults, 1960-2002. JAMA. 2005;295:1773–81.CrossRefGoogle Scholar
  20. 20.
    Dietz WH. Prevalence of the metabolic syndrome among US adults, findings from the Third National Health and Nutrition Examination Survey. JAMA. 2002;287:356–9.PubMedCrossRefGoogle Scholar
  21. 21.
    Yanovski SZ, Avila NA, Hubbard VS. Visceral adipose tissue differences in black and white women. Am J Clin Nutr. 1995;61:765–71.PubMedGoogle Scholar
  22. 22.
    Arsenault BJ, Pibarot P, Despres JP. The quest for the optimal assessment of global cardiovascular risk: are traditional risk factors and metabolic syndrome partners in crime? Cardiology. 2009;113:35–49.PubMedCrossRefGoogle Scholar
  23. 23.
    Despres JP, Lemieux I, Bergeron J, et al. Abdominal obesity and the metabolic syndrome: contribution to global cardiometabolic risk. Arterioscler Thromb Vasc Biol. 2008;28:1039–49.PubMedCrossRefGoogle Scholar
  24. 24.
    Arsenault BJ, Lemieux I, Despres JP, et al.: The hypertriglyceridemic-waist phenotype and the risk of coronary artery disease: results from the EPIC-Norfolk prospective population study. CMAJ 2010, early releaseGoogle Scholar
  25. 25.
    Sam S, Haffner S, Davidson MH, et al. Hypertriglyceridemic waist phenotype predicts increased visceral fat in subjects with type 2 diabetes. Diabetes Care. 2009;32:1916–20.PubMedCrossRefGoogle Scholar
  26. 26.
    Lemieux I, Almeras N, Mauriege P, et al. Prevalence of “hypertriglyceride waist” in men who participated in the Quebec Health Survey: association with atherogenic and diabetogenic metabolic risk factors. Can J Cardiol. 2002;18:725–32.PubMedGoogle Scholar
  27. 27.
    Sumner AE, Vega GL, Genovese DJ. Normal triglyceride levels despite insulin resistance in African Americans: role of lipoprotein lipase. Metabolism Clinical and Experimental. 2005;54:902–9.PubMedGoogle Scholar
  28. 28.
    Ross R, Aru J, Freeman J, et al. Abdominal adiposity and insulin resistance in obese men. Am J Physiol Endocrinol Metab. 2002;282:E657–63.PubMedGoogle Scholar
  29. 29.
    Porter SA, Massaro JM, Hoffman U, et al. Abdominal subcutaneous adipose tissue: a protective fat depot? Diabetes Care. 2009;32:1068–75.PubMedCrossRefGoogle Scholar
  30. 30.
    Bajaj HS, Brennan DM, Hoogwerf BJ. Clinical utility of waist circumference in predicting all cause mortality in a preventive cardiology clinic population. A précis database study. Obesity. 2009;17:1615–20.PubMedCrossRefGoogle Scholar
  31. 31.
    Stefan N, Kantartzis K, Machann J, et al. Identification and characterization of metabolically benign obesity in humans. Arch Intern Med. 2008;168:1609–16.PubMedCrossRefGoogle Scholar
  32. 32.
    Wildman RP, Muntner P, Reynolds K, et al. The obese without cardiometabolic risk factor clustering and the normal weight with cardiometabolic risk factor clustering. Arch Intern Med. 2008;168:1617–24.PubMedCrossRefGoogle Scholar
  33. 33.
    Fontaine KR, Redden DT, Wang C, et al. Years of life lost due to obesity. JAMA. 2003;289:187–93.PubMedCrossRefGoogle Scholar
  34. 34.
    Reis JP, Araneta MR, Wingard DL, et al. Overall obesity and abdominal adiposity as predictors of mortality in U.S. White and Black adults. Ann Epidemiol. 2009;19:134–42.PubMedCrossRefGoogle Scholar
  35. 35.
    Carnethon M, Lynch EB, Dyer AR, et al. Comparison of risk factors for cardiovascular mortality in Black and White adults. Arch Intern Med. 2006;166:1196–202.PubMedCrossRefGoogle Scholar
  36. 36.
    Jakicic JM, Gregg E, Knowler W, et al. Activity patterns of obese adults with type 2 diabetes in look AHEAD study. Med Sci Sports Exerc. 2010;42:1995–2005.PubMedCrossRefGoogle Scholar
  37. 37.
    Myers J, Kaykha A, George S, et al. Fitness versus physical activity patterns in predicting mortality in men. Am J Med. 2004;117:912–8.PubMedCrossRefGoogle Scholar
  38. 38.
    Green TL, Darity Jr WA. Under the skin: using theories from biology and the social sciences to explore the mechanism behind the black white health gap. Am J Public Health. 2010;100 Suppl 1:S36–40.PubMedCrossRefGoogle Scholar
  39. 39.
    Diabetes Prevention Program Research Group. Impact of intensive lifestyle and metformin therapy on cardiovascular disease risk factors in the diabetes prevention program. Diabetes Care. 2005;28:888–94.CrossRefGoogle Scholar
  40. 40.
    Dagogo-Jack S, Egbuonu N, Edeoga C. Principles and practice of nonpharmacological interventions to reduce cardiometabolic risk. Med Princ Pract. 2010;19:167–75. This is a comprehensive review of landmark clinical intervention trials for diabetes prevention, and an overview of the literature on dietary and lifestyle interventions to prevent heart disease.PubMedCrossRefGoogle Scholar
  41. 41.
    • The Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (ALLHAT). JAMA 2002, 288: 298-299.Google Scholar
  42. 42.
    Stampfer MJ, Ridker PM, Dzau VJ. Risk factor criteria. Circulation. 2004;109:IV-3–5.CrossRefGoogle Scholar
  43. 43.
    Hill JM, Zalos G, Halcox JPJ, et al. Circulating endothelial progenitor cells, vascular function, and cardiovascular risk. NEJM. 2003;348:593–600.PubMedCrossRefGoogle Scholar
  44. 44.
    Werner N, Kosiol S, Schiegl T, et al. Circulating endothelial progenitor cells and cardiovascular outcomes. NEJM. 2005;353:999–1007.PubMedCrossRefGoogle Scholar
  45. 45.
    Sakuma N, Saeki T, Ito T, et al. HDL2 can inhibit further oxidative modification of partially oxidized LDL. J Atheroscler Thromb. 2010;17:229–34.PubMedGoogle Scholar
  46. 46.
    Kullo IJ, Ding K. Patterns of population differentiation of candidate genes for cardiovascular disease. BMC Genet. 2007;8:48.PubMedCrossRefGoogle Scholar
  47. 47.
    Dwyer JH, Allayee H, Dwyer KM, et al. Arachidonate 5-lipoxygenase promoter genotype, dietary arachidonic acid, and atherosclerosis. N Engl J Med. 2004;350:29–37.PubMedCrossRefGoogle Scholar
  48. 48.
    Maznyczka A, Braund P, Mangino M, Samani NJ. Arachidonate 5-lipoxygenase (5-LO) promoter genotype and risk of myocardial infarction: a case-control study. Atherosclerosis. 2008;199:328–32.PubMedCrossRefGoogle Scholar
  49. 49.
    Fisher NDL, Hurwitz S, Jeunemaitre X, et al. Familial aggregation of low-renin hypertension. Hypertension. 2002;39:914–8.PubMedCrossRefGoogle Scholar
  50. 50.
    Pitzalis MV, Sarzani R, Dessi-Fulgheri P, et al. Allelic variants of natriuretic peptide receptor genes are associated with family history of hypertension and cardiovascular phenotype. J Hypertens. 2003;21:1491–6.PubMedCrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media, LLC 2011

Authors and Affiliations

  1. 1.Pritzker School of MedicineUniversity of ChicagoChicagoUSA
  2. 2.Division of Endocrinology, Diabetes & MetabolismUniversity of Tennessee Health Science CenterMemphisUSA

Personalised recommendations