Socioeconomic and racial/ethnic differentials of C-reactive protein levels: a systematic review of population-based studies.
BACKGROUND
Socioeconomic and racial/ethnic factors strongly influence cardiovascular disease outcomes and risk factors. C-reactive protein (CRP), a non-specific marker of inflammation, is associated with cardiovascular risk, and knowledge about its distribution in the population may help direct preventive efforts. A systematic review was undertaken to critically assess CRP levels according to socioeconomic and racial/ethnic factors.


METHODS
Medline was searched through December 2006 for population-based studies examining CRP levels among adults with respect to indicators of socioeconomic position (SEP) and/or race/ethnicity. Bibliographies from located studies were scanned and 26 experts in the field were contacted for unpublished work.


RESULTS
Thirty-two relevant articles were located. Cross-sectional (n = 20) and cohort studies (n = 11) were included, as was the control group of one trial. CRP levels were examined with respect to SEP and race/ethnicity in 25 and 15 analyses, respectively. Of 20 studies that were unadjusted or adjusted for demographic variables, 19 found inverse associations between CRP levels and SEP. Of 15 similar studies, 14 found differences between racial/ethnic groups such that whites had the lowest while blacks, Hispanics and South Asians had the highest CRP levels. Most studies also included adjustment for potential mediating variables in the causal chain between SEP or race/ethnicity and CRP. Most of these studies showed attenuated but still significant associations.


CONCLUSIONS
Increasing poverty and non-white race was associated with elevated CRP levels among adults. Most analyses in the literature are underestimating the true effects of racial/ethnic and socioeconomic factors due to adjustment for mediating factors.
Nazmi
Aydin
A
Federal University of Pelotas, Department of Social Medicine, Post-Graduate Program in Epidemiology, Rua Marechal Deodoro 1160, Pelotas, RS, 96020, Brazil. anazmi@gmail.com
Victora
Cesar G
CG
D000328:Adult; D015415:Biomarkers; D002097:C-Reactive Protein / Q000032:analysis*; D002318:Cardiovascular Diseases / Q000175:diagnosis / Q000453:epidemiology / Q000208:ethnology*; D003710:Demography; D006305:Health Status Indicators; D006801:Humans; D044469:Racial Groups / Q000208:ethnology / Q000706:statistics & numerical data; D012923:Social Class; D012959:Socioeconomic Factors
D015415:Biomarkers; D002097:C-Reactive Protein
Epidemiology. 2002 Sep;13(5):561-8
12192226
Int J Epidemiol. 1997 Feb;26(1):224-7
9126524
Eur J Epidemiol. 2006;21(1):55-60
16450207
Ann Epidemiol. 2004 Mar;14(3):188-94
15036222
Bull World Health Organ. 2005 Feb;83(2):118-26
15744404
Circulation. 2004 Apr 27;109(16):1914-7
15117860
Lancet. 2000 Jul 22;356(9226):279-84
11071182
Circulation. 2000 Dec 19;102(25):3137-47
11120707
Am Heart J. 2006 Sep;152(3):593-8
16923436
Diabetes. 2004 Mar;53(3):693-700
14988254
J Natl Cancer Inst. 1991 Apr 17;83(8):526-7
2005635
Int J Epidemiol. 2005 Apr;34(2):327-34
15659460
Arterioscler Thromb Vasc Biol. 2000 Apr;20(4):1052-6
10764672
Int J Epidemiol. 2004 Oct;33(5):1072-9
15256527
N Engl J Med. 2004 Apr 1;350(14):1387-97
15070788
Am J Epidemiol. 2006 Apr 1;163(7):622-8
16421236
Circulation. 1999 Jan 19;99(2):237-42
9892589
Lancet. 2005 Dec 3;366(9501):1954-9
16325697
Am J Cardiol. 2001 Sep 15;88(6):601-7
11564380
Circulation. 1998 May 26;97(20):2007-11
9610529
Psychosom Med. 2003 May-Jun;65(3):347-56
12764206
Int J Epidemiol. 2002 Apr;31(2):294-9
11980782
Health Serv Res. 2003 Dec;38(6 Pt 2):1781-90
14727797
Int J Epidemiol. 2005 Apr;34(2):316-26
15737978
J Rheumatol. 2000 Oct;27(10):2351-9
11036829
Int J Epidemiol. 2005 Apr;34(2):268-75
15319403
Circulation. 2001 Jul 10;104(2):145-50
11447077
Arterioscler Thromb Vasc Biol. 2005 May;25(5):1051-6
15731495
Arterioscler Thromb Vasc Biol. 2004 Aug;24(8):1509-15
15205215
Milbank Q. 2004;82(1):5-99
15016244
BMJ. 1999 Jul 24;319(7204):245-9
10417093
Heart. 2006 Apr;92(4):533-5
16537770
Prev Cardiol. 2001 Summer;4(3):109-114
11828186
JAMA. 1998 Jul 22-29;280(4):356-62
9686553
Int J Epidemiol. 2001 Oct;30 Suppl 1:S48-52
11759851
Lancet. 1999 Nov 27;354(9193):1896-900
10584742
BMJ. 1996 Apr 27;312(7038):1061-5
8616412
Psychosom Med. 2006 May-Jun;68(3):376-81
16738067
Arch Intern Med. 2003 Jan 13;163(1):93-9
12523922
Am Heart J. 2005 Jun;149(6):1066-73
15976790
Clin Chem. 2004 Mar;50(3):574-81
14709450
J Clin Invest. 2003 Jun;111(12):1805-12
12813013
Eur Heart J. 2000 Oct;21(19):1584-90
10988010
Hypertension. 2002 Feb;39(2):197-202
11847183
Eur Heart J. 1999 Jul;20(13):954-9
10361047
Diabetes Metab Res Rev. 2005 Nov-Dec;21(6):515-24
15883967
Arterioscler Thromb Vasc Biol. 2004 Mar;24(3):583-7
14739124
Circulation. 2000 Oct 31;102(18):2165-8
11056086
J Am Coll Cardiol. 2005 Aug 2;46(3):464-9
16053959
N Engl J Med. 1999 Jan 14;340(2):115-26
9887164
Int J Obes Relat Metab Disord. 2004 Aug;28(8):998-1003
15211365
Arterioscler Thromb Vasc Biol. 2005 Oct;25(10):2197-202
16123322
Int J Epidemiol. 2006 Aug;35(4):922-31
16565153
Diabetes. 2002 May;51(5):1596-600
11978661
BMJ. 1998 May 30;316(7145):1631-5
9603744
Brain Behav Immun. 2006 Sep;20(5):498-504
16330181
Circulation. 1998 Aug 25;98(8):731-3
9727541
Public Health Nutr. 2001 Apr;4(2B):611-24
11683554
J Epidemiol Community Health. 2003 Sep;57(9):730-3
12933781
Thromb Haemost. 2005 May;93(5):955-63
15886815
Circulation. 2003 Nov 11;108(19):2317-22
14568895
Eur Heart J. 2000 Jul;21(14):1141-51
10924297
N Engl J Med. 1997 Apr 3;336(14):973-9
9077376
Circulation. 2003 Dec 16;108(24):2993-9
14638538
J Am Geriatr Soc. 2001 Feb;49(2):109-16
11207863
Int J Epidemiol. 2001 Aug;30(4):668-77
11511581
Arterioscler Thromb Vasc Biol. 2005 Jun;25(6):1091-4
15923540
Eur J Cardiovasc Prev Rehabil. 2005 Feb;12(1):68-74
15703509
Clin Chem. 2003 Apr;49(4):686-90
12651834
Int J Obes Relat Metab Disord. 2001 Sep;25(9):1327-31
11571595