title: Biological and behavioural explanations of social inequalities in coronary heart disease: the Whitehall II study.
abstract: OBJECTIVE
  We determined the degree to which metabolic syndrome components, inflammation and health behaviours account for the social gradient in CHD.
  
  
  METHODS
  A total of 5312 men, initially aged 39 to 63 years, were followed for 13.1 years for incident coronary death or non-fatal myocardial infarction according to socioeconomic position (employment grade). The contribution of explanatory factors to socioeconomic differences in CHD was assessed by the reduction in hazard ratios computed using Cox models. The effects of measurement error were taken into account.
  
  
  RESULTS
  Coronary events were more common in lower employment grades than in higher, with a hazard ratio (relative index of inequality) of 2.2 (95% CI 1.3-3.7), after adjustment for age and ethnic group. Behavioural risk factors (mainly smoking and diet) explained a third of the socioeconomic gradient in CHD incidence. Components of the metabolic syndrome and inflammatory markers predicted CHD incidence and also explained a third of the gradient. Combined, these two groups of predictors, i.e. behavioural and biological, accounted for over half of the socioeconomic gradient in incident CHD. Adding body height as a marker of the effects of early life increased this figure to about 60%.
  
  
  CONCLUSIONS
  A major question has been how someone's socioeconomic position can lead to increased risk of CHD. Socioeconomic differences in components of the metabolic syndrome (and inflammatory markers) provide part of the answer. This was, to an important degree, independent of the contribution of health behaviours to the socioeconomic differentials in CHD.
authors.affiliation: Department of Epidemiology and Public Health, University College London, London, WC1E 6BT, UK. m.marmot@ucl.ac.uk
authors.forename: M G
authors.initials: MG
authors.lastname: Marmot
authors.forename: M J
authors.initials: MJ
authors.lastname: Shipley
authors.forename: H
authors.initials: H
authors.lastname: Hemingway
authors.forename: J
authors.initials: J
authors.lastname: Head
authors.forename: E J
authors.initials: EJ
authors.lastname: Brunner
mesh_terms: D000328:Adult; D015992:Body Mass Index; D002097:C-Reactive Protein / Q000378:metabolism; D002423:Cause of Death; D003327:Coronary Disease / Q000453:epidemiology* / Q000401:mortality / Q000523:psychology*; D003971:Diastole; D005500:Follow-Up Studies; D006801:Humans; D007249:Inflammation / Q000097:blood / Q000453:epidemiology; D008131:London; D008875:Middle Aged; D016016:Proportional Hazards Models; D012042:Registries; D012307:Risk Factors; D012907:Smoking / Q000453:epidemiology; D012919:Social Behavior; D012959:Socioeconomic Factors; D013599:Systole; D049629:Waist-Hip Ratio
chemical_list: D002097:C-Reactive Protein
references.citation: Lancet. 1997 Jul 26;350(9073):235-9
references.pmid: 9242799
references.citation: Arterioscler Thromb Vasc Biol. 2000 Jul;20(7):1842-7
references.pmid: 10894827
references.citation: Eur J Epidemiol. 2007;22(10):675-83
references.pmid: 17668278
references.citation: N Engl J Med. 2001 Jul 12;345(2):99-106
references.pmid: 11450679
references.citation: Methods Inf Med. 1990 Sep;29(4):354-61
references.pmid: 2233383
references.citation: N Engl J Med. 2004 Apr 1;350(14):1387-97
references.pmid: 15070788
references.citation: BMJ. 1997 May 17;314(7092):1472-6
references.pmid: 9167568
references.citation: J Epidemiol Community Health. 2003 Feb;57(2):147-53
references.pmid: 12540692
references.citation: J Intern Med. 2000 Feb;247(2):188-97
references.pmid: 10692081
references.citation: Int J Epidemiol. 2004 Apr;33(2):289-96
references.pmid: 15082628
references.citation: JAMA. 1998 Jun 3;279(21):1703-8
references.pmid: 9624022
references.citation: Lancet. 1991 Jun 8;337(8754):1387-93
references.pmid: 1674771
references.citation: Am J Public Health. 1994 Jun;84(6):932-7
references.pmid: 8203689
references.citation: Ann N Y Acad Sci. 1999;896:3-15
references.pmid: 10681884
references.citation: Br Med Bull. 1997 Jan;53(1):3-9
references.pmid: 9158280
references.citation: Circulation. 2002 Nov 19;106(21):2659-65
references.pmid: 12438290
references.citation: Int J Epidemiol. 2006 Aug;35(4):922-31
references.pmid: 16565153
references.citation: Int J Epidemiol. 2005 Apr;34(2):251-6
references.pmid: 15576467
references.citation: Stat Med. 2007 Jan 30;26(2):426-42
references.pmid: 16220522
references.citation: Am J Epidemiol. 2007 Apr 1;165(7):828-37
references.pmid: 17244635
references.citation: Circulation. 2005 Jun 14;111(23):3071-7
references.pmid: 15939818
references.citation: BMJ. 2007 Jul 21;335(7611):136
references.pmid: 17615182
references.citation: Diabetologia. 1997 Nov;40(11):1341-9
references.pmid: 9389428
references.citation: J Epidemiol Community Health. 1982 Jun;36(2):102-8
references.pmid: 7119652
references.citation: BMJ. 2006 Apr 15;332(7546):878-82
references.pmid: 16510492
references.citation: Circulation. 1994 Jul;90(1):583-612
references.pmid: 8026046
references.citation: Am J Epidemiol. 1996 Nov 15;144(10):934-42
references.pmid: 8916504
references.citation: N Z Med J. 1993 May 26;106(956):193-6
references.pmid: 8341437
references.citation: BMJ. 1998 May 30;316(7145):1636-42
references.pmid: 9603745
references.citation: Am J Clin Nutr. 2008 May;87(5):1414-21
references.pmid: 18469266
references.citation: Lancet. 1984 May 5;1(8384):1003-6
references.pmid: 6143919
references.citation: N Engl J Med. 2001 May 3;344(18):1343-50
references.pmid: 11333990
references.citation: Biostatistics. 2006 Apr;7(2):213-24
references.pmid: 16192414
references.citation: Lancet. 1996 Apr 13;347(9007):1008-13
references.pmid: 8606563
references.citation: Br J Nutr. 2001 Sep;86(3):405-14
references.pmid: 11570993
references.citation: Am J Public Health. 1999 Mar;89(3):315-21
references.pmid: 10076479
references.citation: BMJ. 2006 Mar 4;332(7540):521-5
references.pmid: 16428252
references.citation: Am J Epidemiol. 2002 Apr 15;155(8):683-7
references.pmid: 11943683
references.citation: Lancet. 2005 Dec 3;366(9501):1954-9
references.pmid: 16325697
references.citation: Mol Genet Metab. 2007 Apr;90(4):422-8
references.pmid: 17123852
references.citation: Int J Epidemiol. 2003 Aug;32(4):600-6
references.pmid: 12913036
references.citation: Am J Public Health. 1996 Apr;86(4):486-96
references.pmid: 8604778
references.citation: J Epidemiol Community Health. 2000 Mar;54(3):178-84
references.pmid: 10746111
references.citation: Soc Sci Med. 2003 Apr;56(7):1397-410
references.pmid: 12614692