Cost-effectiveness of preparticipation screening for prevention of sudden cardiac death in young athletes

Annals of Internal Medicine

Volumn 152, Issue 5, 2010, Pages 276-286

  Wheeler, Matthew T ^a   Heidenreich, Paul A ^b   Froelicher, Victor F ^b   Hlatky, Mark A ^a   Ashley, Euan A ^a  

^a STANFORD UNIVERSITY SCHOOL OF MEDICINE   (United States)

^b VA PALO ALTO HEALTH CARE SYSTEM   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

ADOLESCENT; ADULT; ANAMNESIS; ARTICLE; ATHLETE; CARDIOVASCULAR PERFORMANCE; COLLEGE STUDENT; CONTROLLED STUDY; COST EFFECTIVENESS ANALYSIS; ELECTROCARDIOGRAPHY; FEMALE; HEALTH CARE COST; HEALTH CARE FINANCING; HEART DISEASE; HIGH SCHOOL STUDENT; HUMAN; MALE; MEDICAL DECISION MAKING; PHYSICAL EXAMINATION; PRIORITY JOURNAL; QUALITY ADJUSTED LIFE YEAR; RISK REDUCTION; SCREENING TEST; SPORT; SUDDEN DEATH; VITAL STATISTICS; CARDIOVASCULAR DISEASE; COMPUTER SIMULATION; COST BENEFIT ANALYSIS; DECISION SUPPORT SYSTEM; ECONOMICS; MASS SCREENING; METHODOLOGY; PREVALENCE; SENSITIVITY AND SPECIFICITY; STUDENT;

ADOLESCENT; ADULT; ATHLETES; CARDIOVASCULAR DISEASES; COMPUTER SIMULATION; COST-BENEFIT ANALYSIS; DEATH, SUDDEN, CARDIAC; DECISION SUPPORT TECHNIQUES; ELECTROCARDIOGRAPHY; FEMALE; HUMANS; MALE; MASS SCREENING; PHYSICAL EXAMINATION; PREVALENCE; SENSITIVITY AND SPECIFICITY; STUDENTS; YOUNG ADULT;

EID: 77950353045     PISSN: 00034819     EISSN: 15393704     Source Type: Journal    
DOI: 10.7326/0003-4819-152-5-201003020-00005     Document Type: Article

References (90)

1. Maron BJ. Hypertrophic cardiomyopathy and other causes of sudden cardiac death in young competitive athletes, with considerations for preparticipation screening and criteria for disqualification. Cardiol Clin. 2007;25:399-414, vi. [PMID: 17961794]
2. Drezner JA, Chun JS, Harmon KG, Derminer L. Survival trends in the United States following exercise-related sudden cardiac arrest in the youth: 2000-2006. Heart Rhythm. 2008;5:794-799 [PMID: 18486566]
3. Corrado D, Basso C, Rizzoli G, Schiavon M, Thiene G. Does sports activity enhance the risk of sudden death in adolescents and young adults? J Am Coll Cardiol. 2003;42:1959-1963 [PMID: 14662259]
4. Thompson PD, Franklin BA, Balady GJ, Blair SN, Corrado D, Estes NA 3rd, et al; American Heart Association Council on Nutrition, Physical Activity, and Metabolism. Exercise and acute cardiovascular events placing the risks into perspective: a scientific statement from the American Heart Association Council on Nutrition, Physical Activity, and Metabolism and the Council on Clinical Cardiology. Circulation. 2007;115:2358-2368 [PMID: 17468391]
5. Van Camp SP, Bloor CM, Mueller FO, Cantu RC, Olson HG. Nontraumatic sports death in high school and college athletes. Med Sci Sports Exerc. 1995;27:641-647 [PMID: 7674867]
6. Tanaka Y, Yoshinaga M, Anan R, Tanaka Y, Nomura Y, Oku S, et al. Usefulness and cost effectiveness of cardiovascular screening of young adolescents. Med Sci Sports Exerc. 2006;38:2-6. [PMID: 16394946]
7. Maron BJ, Shirani J, Poliac LC, Mathenge R, Roberts WC, Mueller FO. Sudden death in young competitive athletes. Clinical, demographic, and pathological profiles. JAMA. 1996;276:199-204. [PMID: 8667563]
8. Pelliccia A, Di Paolo FM, Corrado D, Buccolieri C, Quattrini FM, Pisicchio C, et al. Evidence for efficacy of the Italian national pre-participation screening programme for identification of hypertrophic cardiomyopathy in competitive athletes. Eur Heart J. 2006;27:2196-2200 [PMID: 16831826]
9. Corrado D, Basso C, Pavei A, Michieli P, Schiavon M, Thiene G. Trends in sudden cardiovascular death in young competitive athletes after implementation of a preparticipation screening program. JAMA. 2006;296:1593-1601 [PMID: 17018804]
10. Myerburg RJ, Vetter VL. Electrocardiograms should be included in preparticipation screening of athletes. Circulation. 2007;116:2616-26; discussion 2626. [PMID: 18040041]
11. Chaitman BR. An electrocardiogram should not be included in routine preparticipation screening of young athletes. Circulation. 2007;116:2610-4; discussion 2615. [PMID: 18040040]
12. Maron BJ, Douglas PS, Graham TP, Nishimura RA, Thompson PD. Task Force 1: preparticipation screening and diagnosis of cardiovascular disease in athletes. J Am Coll Cardiol. 2005;45:1322-1326 [PMID: 15837281]
13. Maron BJ, Thompson PD, Ackerman MJ, Balady G, Berger S, Cohen D, et al; American Heart Association Council on Nutrition, Physical Activity, and Metabolism. Recommendations and considerations related to preparticipation screening for cardiovascular abnormalities in competitive athletes: 2007 update: a scientific statement from the American Heart Association Council on Nutrition, Physical Activity, and Metabolism: endorsed by the American College of Cardiology Foundation. Circulation. 2007;115:1643-2455 [PMID: 17353433]
14. Maron BJ, Thompson PD, Puffer JC, McGrew CA, Strong WB, Douglas PS, et al. Cardiovascular preparticipation screening of competitive athletes. A statement for health professionals from the Sudden Death Committee (clinical cardiology) and Congenital Cardiac Defects Committee (cardiovascular disease in the young), American Heart Association. Circulation. 1996;94:850-856 [PMID: 8772711]
15. Maron BJ, Thompson PD, Puffer JC, McGrew CA, Strong WB, Douglas PS, et al. Cardiovascular preparticipation screening of competitive athletes: addendum: an addendum to a statement for health professionals from the Sudden Death Committee (Council on Clinical Cardiology) and the Congenital Cardiac Defects Committee (Council on Cardiovascular Disease in the Young), American Heart Association. Circulation. 1998;97:2294. [PMID: 9631885]
16. Italian Ministry of Health. Decree of the Italian Ministry of Health, 18 February 1982. Norme per la tutela sanitaria dell'attivita sportiva agnostica [Rules concerning the medical protection of athletic activity]. Gazzetta Ufficiale. 1982;5 March:63.
17. Corrado D, Pelliccia A, Bjørnstad HH, Vanhees L, Biffi A, Borjesson M, et al; Study Group of Sport Cardiology of the Working Group of Cardiac Rehabilitation and Exercise Physiology and the Working Group of Myocardial and Pericardial Diseases of the European Society of Cardiology. Cardiovascular preparticipation screening of young competitive athletes for prevention of sudden death: proposal for a common European protocol. Consensus Statement of the Study Group of Sport Cardiology of the Working Group of Cardiac Rehabilitation and Exercise Physiology and the Working Group of Myocardial and Pericardial Diseases of the European Society of Cardiology. Eur Heart J. 2005;26: 516-524 [PMID: 15689345]
18. International Olympic Committee Medical Commission. Sudden cardiovascular death in sport. Lausanne recommendations: preparticipation cardiovascular screening. Vol. 2008. Lausanne: International Olympic Committee Medical Commission; 2004.
19. MacAuley D. Olympic dreams. BMJ. 2008;337:a739.
20. Leslie LK, Alexander ME, Trikalinos TA, Cohen JT, Parsons SK, New-burger JW. Reexamining the emperor's new clothes: ambiguities in current cardiac screening recommendations for youth with attention deficit hyperactivity disorder. Circ Cardiovasc Qual Outcomes. 2008;1:134-137 [PMID: 20031801]
21. Vetter VL, Elia J, Erickson C, Berger S, Blum N, Uzark K, et al; American Heart Association Council on Cardiovascular Disease in the Young Congenital Cardiac Defects Committee. Cardiovascular monitoring of children and adolescents with heart disease receiving medications for attention deficit/hyperactivity disorder [corrected]: a scientific statement from the American Heart Association Council on Cardiovascular Disease in the Young, Congenital Cardiac Defects Committee, and the Council on Cardiovascular Nursing. Circulation. 2008;117: 2407-2423 [PMID: 18427125]
22. Fuller CM. Cost effectiveness analysis of screening of high school athletes for risk of sudden cardiac death. Med Sci Sports Exerc. 2000;32:887-890 [PMID: 10795776]
23. Risser WL, Hoffman HM, Bellah GG Jr, Green LW. A cost-benefit analysis of preparticipation sports examinations of adolescent athletes. J Sch Health. 1985; 55:270-273 [PMID: 3932779]
24. Weinstein MC, Siegel JE, Gold MR, Kamlet MS, Russell LB. Recommendations of the Panel on Cost-effectiveness in Health and Medicine. JAMA. 1996; 276:1253-1258 [PMID: 8849754]
25. Miniño AM, Heron MP, Murphy SL, Kochanek KD; Centers for Disease Control and Prevention National Center for Health Statistics National Vital Statistics System. Deaths: final data for 2004. Natl Vital Stat Rep. 2007;55:1-119. [PMID: 17867520]
26. Fuller CM, McNulty CM, Spring DA, Arger KM, Bruce SS, Chryssos BE, et al. Prospective screening of 5,615 high school athletes for risk of sudden cardiac death. Med Sci Sports Exerc. 1997;29:1131-1138 [PMID: 9309622]
27. Wilson MG, Basavarajaiah S, Whyte GP, Cox S, Loosemore M, Sharma S. Efficacy of personal symptom and family history questionnaires when screening for inherited cardiac pathologies: the role of electrocardiography. Br J Sports Med. 2008;42:207-211 [PMID: 17717062]
28. Nistri S, Thiene G, Basso C, Corrado D, Vitolo A, Maron BJ. Screening for hypertrophic cardiomyopathy in a young male military population. Am J Cardiol. 2003;91:1021-3, A8. [PMID: 12686356]
29. Maron BJ, Bodison SA, Wesley YE, Tucker E, Green KJ. Results of screening a large group of intercollegiate competitive athletes for cardiovascular disease. J Am Coll Cardiol. 1987;10:1214-1221 [PMID: 2960727] (Pubitemid 18004671)
30. Weidenbener EJ, Krauss MD, Waller BF, Taliercio CP. Incorporation of screening echocardiography in the preparticipation exam. Clin J Sport Med. 1995;5:86-89 [PMID: 7882118]
31. Smith J, Laskowski ER. The preparticipation physical examination: Mayo Clinic experience with 2,739 examinations. Mayo Clin Proc. 1998;73:419-429 [PMID: 9581581] (Pubitemid 28231980)
32. Pelliccia A, Culasso F, Di Paolo FM, Accettura D, Cantore R, Castagna W, et al. Prevalence of abnormal electrocardiograms in a large, unselected population undergoing pre-participation cardiovascular screening. Eur Heart J. 2007;28: 2006-2010 [PMID: 17623682]
33. American Medical Association. Medicare RBRVS 2008: The Physician's Guide. Chicago: American Medical Assoc; 2008.
34. Office of Statewide Health Planning and Development. Annual Financial Data: Hospital Chargemasters. Sacramento: California Office of Statewide Health Planning and Development; 2007.
35. National Center for Health Statistics. Health, United States, 2007, With Chartbook on Trends in the Health of Americans. Hyattsville, MD: National Center for Health Statistics; 2007. DHHS publication no. 2007-11232
36. Yock CA, Boothroyd DB, Owens DK, Garber AM, Hlatky MA. Cost-effectiveness of bypass surgery versus stenting in patients with multivessel coronary artery disease. Am J Med. 2003;115:382-389 [PMID: 14553874]
37. Chan PS, Vijan S, Morady F, Oral H. Cost-effectiveness of radiofrequency catheter ablation for atrial fibrillation. J Am Coll Cardiol. 2006;47:2513-2520 [PMID: 16781382]
38. Sanders GD, Hlatky MA, Owens DK. Cost-effectiveness of implantable cardioverter-defibrillators. N Engl J Med. 2005;353:1471-1480 [PMID: 16207849]
39. Sofi F, Capalbo A, Pucci N, Giuliattini J, Condino F, Alessandri F, et al. Cardiovascular evaluation, including resting and exercise electrocardiography, before participation in competitive sports: cross sectional study. BMJ. 2008;337: a346. [PMID: 18599474]
40. Pelliccia A, Maron BJ. Preparticipation cardiovascular evaluation of the competitive athlete: perspectives from the 30-year Italian experience [Editorial]. Am J Cardiol. 1995;75:827-829 [PMID: 7717289]
41. Basavarajaiah S, Wilson M, Whyte G, Shah A, McKenna W, Sharma S. Prevalence of hypertrophic cardiomyopathy in highly trained athletes: relevance to pre-participation screening. J Am Coll Cardiol. 2008;51:1033-1039 [PMID: 18325444]
42. Basavarajaiah S, Boraita A, Whyte G, Wilson M, Carby L, Shah A, et al. Ethnic differences in left ventricular remodeling in highly-trained athletes relevance to differentiating physiologic left ventricular hypertrophy from hypertrophic cardiomyopathy. J Am Coll Cardiol. 2008;51:2256-2262 [PMID: 18534273]
43. Pelliccia A, Di Paolo FM, Maron BJ. The athlete's heart: remodeling, electrocardiogram and preparticipation screening. Cardiol Rev. 2002;10:85-90. [PMID: 11895574] (Pubitemid 34246656)
44. Pelliccia A, Maron BJ, Culasso F, Di Paolo FM, Spataro A, Biffi A, et al. Clinical significance of abnormal electrocardiographic patterns in trained athletes. Circulation. 2000;102:278-284 [PMID: 10899089] (Pubitemid 30457576)
45. Sharma S, Whyte G, Elliott P, Padula M, Kaushal R, Mahon N, et al. Electrocardiographic changes in 1000 highly trained junior elite athletes. Br J Sports Med. 1999;33:319-324 [PMID: 10522633] (Pubitemid 29460605)
46. Magalski A, Maron BJ, Main ML, McCoy M, Florez A, Reid KJ, et al. Relation of race to electrocardiographic patterns in elite American football players. J Am Coll Cardiol. 2008;51:2250-2255 [PMID: 18534272]
47. Lawless CE, Best TM. Electrocardiograms in athletes: interpretation and diagnostic accuracy. Med Sci Sports Exerc. 2008;40:787-798 [PMID: 18408622]
48. Maron BJ, Zipes DP. Introduction: eligibility recommendations for competitive athletes with cardiovascular abnormalities-general considerations. J Am Coll Cardiol. 2005;45:1318-1321 [PMID: 15837280]
49. Mittmann N, Trakas K, Risebrough N, Liu BA. Utility scores for chronic conditions in a community-dwelling population. Pharmacoeconomics. 1999;15: 369-376 [PMID: 10537955]
50. Cantor SB, Ganiats TG. Incremental cost-effectiveness analysis: the optimal strategy depends on the strategy set. J Clin Epidemiol. 1999;52:517-522 [PMID: 10408990]
51. Nora M, Zimmerman F, Ow P, Fenner P, Marek J. Preliminary findings of ECG screening in 9,125 young adults [Abstract 3718]. Circulation. 2007;116:845.
52. Corrado D, Basso C, Schiavon M, Thiene G. Screening for hypertrophic cardiomyopathy in young athletes. N Engl J Med. 1998;339:364-369 [PMID: 9691102]
53. Thompson TR, Andrish JT, Bergfeld JA. A prospective study of preparticipation sports examinations of 2670 young athletes: method and results. Cleve Clin Q. 1982;49:225-233 [PMID: 7168912]
54. Paffenbarger RS Jr, Hyde RT, Wing AL, Hsieh CC. Physical activity, all-cause mortality, and longevity of college alumni. N Engl J Med. 1986;314: 605-613 [PMID: 3945246]
55. Sung L, Young NL, Greenberg ML, McLimont M, Samanta T, Wong J, et al. Health-related quality of life (HRQL) scores reported from parents and their children with chronic illness differed depending on utility elicitation method. J Clin Epidemiol. 2004;57:1161-1166 [PMID: 15567632]
56. Griebsch I, Coast J, Brown J. Quality-adjusted life-years lack quality in pediatric care: a critical review of published cost-utility studies in child health. Pediatrics. 2005;115:e600-14. [PMID: 15867026]
57. Kaplan RM, Bush JW. Health-related quality of life measurement for evaluation research and policy analysis. Health Psychology. 1982;1:61-80.
58. Tengs TO, Adams ME, Pliskin JS, Safran DG, Siegel JE, Weinstein MC, et al. Five-hundred life-saving interventions and their cost-effectiveness. Risk Anal. 1995;15:369-390 [PMID: 7604170]
59. Nichol G, Valenzuela T, Roe D, Clark L, Huszti E, Wells GA. Cost effectiveness of defibrillation by targeted responders in public settings. Circulation. 2003;108:697-703. [PMID: 12900345]
60. Gold MR, Siegel JE, Russell LB, Weinstein MC. Cost-Effectiveness in Health and Medicine. New York: Oxford Univ Pr; 1996.
61. Maron BJ, Gardin JM, Flack JM, Gidding SS, Kurosaki TT, Bild DE. Prevalence of hypertrophic cardiomyopathy in a general population of young adults. Echocardiographic analysis of 4111 subjects in the CARDIA Study. Coronary Artery Risk Development in (Young) Adults. Circulation. 1995;92:785-789 [PMID: 7641357]
62. Arola A, Jokinen E, Ruuskanen O, Saraste M, Pesonen E, Kuusela AL, et al. Epidemiology of idiopathic cardiomyopathies in children and adolescents. A nationwide study in Finland. Am J Epidemiol. 1997;146: 385-393 [PMID: 9290498] (Pubitemid 27377515)
63. Agnarsson UT, Hardarson T, Hallgrimsson J, Sigfusson N. The prevalence of hypertrophic cardiomyopathy in men: an echocardiographic population screening study with a review of death records. J Intern Med. 1992;232:499-506. [PMID: 1474350] (Pubitemid 23024317)
64. Davis JA, Cecchin F, Jones TK, Portman MA. Major coronary artery anomalies in a pediatric population: incidence and clinical importance. J Am Coll Cardiol. 2001;37:593-597 [PMID: 11216984]
65. Pelliccia A, Spataro A, Maron BJ. Prospective echocardiographic screening for coronary artery anomalies in 1,360 elite competitive athletes. Am J Cardiol. 1993;72:978-979 [PMID: 8213561]
66. Yamanaka O, Hobbs RE. Coronary artery anomalies in 126,595 patients undergoing coronary arteriography. Cathet Cardiovasc Diagn. 1990;21:28-40. [PMID: 2208265] (Pubitemid 20305231)
67. Pelliccia A, Maron BJ, Spataro A, Proschan MA, Spirito P. The upper limit of physiologic cardiac hypertrophy in highly trained elite athletes. N Engl J Med. 1991;324:295-301. [PMID: 1824720]
68. Kytö V, Saraste A, Voipio-Pulkki LM, Saukko P. Incidence of fatal myocarditis: a population-based study in Finland. Am J Epidemiol. 2007;165:570-574 [PMID: 17237135]
69. Gemayel C, Pelliccia A, Thompson PD. Arrhythmogenic right ventricular cardiomyopathy. J Am Coll Cardiol. 2001;38:1773-1781 [PMID: 11738273]
70. Joseph A, Ackerman D, Talley JD, Johnstone J, Kupersmith J. Manifestations of coronary atherosclerosis in young trauma victims - an autopsy study. J Am Coll Cardiol. 1993;22:459-467 [PMID: 8335815] (Pubitemid 23214558)
71. Lipshultz SE, Sleeper LA, Towbin JA, Lowe AM, Orav EJ, Cox GF, et al. The incidence of pediatric cardiomyopathy in two regions of the United States. N Engl J Med. 2003;348:1647-1655 [PMID: 12711739]
72. Miura K, Nakagawa H, Morikawa Y, Sasayama S, Matsumori A, Hasegawa K, et al. Epidemiology of idiopathic cardiomyopathy in Japan: results from a nationwide survey. Heart. 2002;87:126-130 [PMID: 11796547] (Pubitemid 34098371)
73. Bar-Dayan Y, Elishkevits K, Goldstein L, Goldberg A, Ohana N, Onn E, et al. The prevalence of common cardiovascular diseases among 17-year-old Israeli conscripts. Cardiology. 2005;104:6-9. [PMID: 15942176]
74. Quaglini S, Rognoni C, Spazzolini C, Priori SG, Mannarino S, Schwartz PJ. Cost-effectiveness of neonatal ECG screening for the long QT syndrome. Eur Heart J. 2006;27:1824-1832 [PMID: 16840497]
75. Blangy H, Sadoul N, Coutelour JM, Rebmann JP, Joseph M, Scherrer C, et al. [Prevalence of Brugada syndrome among 35,309 inhabitants of Lorraine screened at a preventive medicine centre]. Arch Mal Coeur Vaiss. 2005;98:175-180 [PMID: 15816318]
76. Gallagher MM, Forleo GB, Behr ER, Magliano G, De Luca L, Morgia V, et al. Prevalence and significance of Brugada-type ECG in 12,012 apparently healthy European subjects. Int J Cardiol. 2008;130:44-48 [PMID: 18054807]
77. Oe H, Takagi M, Tanaka A, Namba M, Nishibori Y, Nishida Y, et al. Prevalence and clinical course of the juveniles with Brugada-type ECG in Japanese population. Pacing Clin Electrophysiol. 2005;28:549-554 [PMID: 15955188]
78. Junttila MJ, Raatikainen MJ, Karjalainen J, Kauma H, Kesäniemi YA, Huikuri HV. Prevalence and prognosis of subjects with Brugada-type ECG pattern in a young and middle-aged Finnish population. Eur Heart J. 2004;25: 874-878 [PMID: 15140536]
79. Vidaillet HJ Jr, Pressley JC, Henke E, Harrell FE Jr, German LD. Familial occurrence of accessory atrioventricular pathways (preexcitation syndrome). N Engl J Med. 1987;317:65-69 [PMID: 3587328] (Pubitemid 17093733)
80. Krahn AD, Manfreda J, Tate RB, Mathewson FA, Cuddy TE. The natural history of electrocardiographic preexcitation in men. The Manitoba Follow-up Study. Ann Intern Med. 1992;116:456-460 [PMID: 1739235]
81. Hyduk A, Croft JB, Ayala C, Zheng K, Zheng ZJ, Mensah GA. Pulmonary hypertension surveillance - United States, 1980-2002. MMWR Surveill Summ. 2005;54:1-28. [PMID: 16280974]
82. Rich S, Dantzker DR, Ayres SM, Bergofsky EH, Brundage BH, Detre KM, et al. Primary pulmonary hypertension. A national prospective study. Ann Intern Med. 1987;107:216-223 [PMID: 3605900]
83. Milewicz DM, Dietz HC, Miller DC. Treatment of aortic disease in patients with Marfan syndrome. Circulation. 2005;111:e150-7. [PMID: 15781745]
84. Pyeritz RE, McKusick VA. The Marfan syndrome: diagnosis and management. N Engl J Med. 1979;300:772-777 [PMID: 370588]
85. Fixler DE, Pastor P, Chamberlin M, Sigman E, Eifler CW. Trends in congenital heart disease in Dallas County births. 1971-1984. Circulation. 1990; 81:137-142 [PMID: 2297821]
86. Fyler D. Report of the New England Regional Infant Cardiac Program [Abstract]. Pediatrics. 1980;65:377-461. (Pubitemid 10054488)
87. National Federation of State High School Associations. 2006-2007 High School Athletics Participation Survey. vol. 2008; 2008. Indianapolis: National Federation of State High School Associations.
88. National Collegiate Athletics Association. 1981-1982 to 2004-05 NCAA Sports Sponsorship and Participation Rates Report. vol. 2008. Indianapolis: National Collegiate Athletics Association; 2007.
89. Miniño AM, Heron MP, Murphy SL, Kochanek KD; Centers for Disease Control and Prevention National Center for Health Statistics National Vital Statistics System. Deaths: final data for 2004. Natl Vital Stat Rep. 2007;55:1-119. [PMID: 17867520]
90. U.S. Census Bureau. Annual Estimates of the Resident Population by Sex and Selected Age Groups for the United States: 1 April 2000 to 1 July 2008. Washington, DC: U.S. Census Bureau; 2009.