 Novel coronary heart disease risk factors at 60–64 years and life course socioeconomic position_ The 1946 British birth cohort_

Novel coronary heart disease risk factors at 60e64 years and lifecourse socioeconomic position: The 1946 British birth cohortRebecca Jonesa , Rebecca Hardy b , Naveed Sattar c , John E. Deanf i eld d , Alun Hughes e ,Diana Kuhc , Emily T. Murray a , Peter H. Whincup a , * , Claudia Thomas a , on behalf of theNSHD Scientif i c and Data Collection Teamsa Population Health Research Institute, St George's, University of London, London, United Kingdomb MRC Unit for Lifelong Health and Ageing, Institute of Epidemiology and Health Care, University College London, London, United Kingdomc British Heart Foundation Glasgow Cardiovascular Research Centre, University of Glasgow, Glasgow, United Kingdomd Vascular Physiology Unit, Institute of Cardiovascular Science, University College of London, United Kingdome National Heart and Lung Institute, Imperial College Academic Health Sciences Centre, London, United Kingdoma r t i c l e i n f oArticle history:Received 26 March 2014Received in revised form19 October 2014Accepted 10 November 2014Available online 18 November 2014Keywords:Socioeconomic positionLife courseInf l ammationEndothelialAdipocyteProinsulinBirth cohorta b s t r a c tSocial disadvantage across the life course is associated with a greater risk of coronary heart disease (CHD)and with established CHD risk factors, but less is known about whether novel CHD risk factors show thesame patterns. The Medical Research Council National Survey of Health and Development was used toinvestigate associations between occupational socioeconomic position during childhood, early adulthoodand middle age and markers of inf l ammation (C-reactive protein, interleukin-6), endothelial function (E-selectin, tissue-plasminogen activator), adipocyte function (leptin, adiponectin) and pancreatic beta cellfunction (proinsulin) measured at 60e64 years. Life course models representing sensitive periods,accumulation of risk and social mobility were compared with a saturated model to ascertain the natureof the relationship between social class across the life course and each of these novel CHD risk factors.For interleukin-6 and leptin, low childhood socioeconomic position alone was associated with high riskfactor levels at 60e64 years, while for C-reactive protein and proinsulin, cumulative effects of low so-cioeconomic position in both childhood and early adulthood were associated with higher (adverse) riskfactor levels at 60e64 years. No associations were observed between socioeconomic position at any lifeperiod with either endothelial marker or adiponectin. Associations for C-reactive protein, interleukin-6,leptin and proinsulin were reduced considerably by adjustment for body mass index and, to a lesserextent, cigarette smoking. In conclusion, socioeconomic position in early life is an important determinantof several novel CHD risk factors. Body mass index may be an important mediator of these relationships.© 2014 The Authors. Published by Elsevier Ireland Ltd. This is an open access article under the CC BYlicense (http://creativecommons.org/licenses/by/3.0/).1. IntroductionIn the UK and other Western countries, social disadvantageacross the life course is a strong determinant of coronary heartdisease (CHD) risk [1e3]. Potential explanations for this socioeco-nomic gradient in CHD risk have centred on socioeconomic differ-ences in the distribution of established risk factors, particularlycigarette smoking, blood pressure, blood lipids and adiposity [4,5].These investigations have included a small number of studies thathave examined the effect of socioeconomic position across the lifecourse on established CHD risk factors, such as body mass index,blood pressure and cholesterol [6,7]. However, a substantialamount of variation in CHD is not explained by adjustment forthese established risk factors [4,5].More recently, several novel risk factors have been identif i ed aspotential predictors of increased CHD risk. These include higherlevels of markers of the inf l ammatory response, C-reactive proteinand interleukin-6, higher levels of markers of endothelial function,E-selectin and tissue plasminogen activator, the adipokine leptinand the pancreatic beta cell function marker proinsulin [8e13]. Incontrast, circulating levels of the adipokine adiponectin areinverselyassociated with CHD risk [14,15]. There is growinginterest* Corresponding author. Population Health Research Institute, St George's, Uni-versity of London, Cranmer Terrace, London SW17 ORE, United Kingdom.E-mail address: pwhincup@sgul.ac.uk (P.H. Whincup).Contents lists available at ScienceDirectAtherosclerosisjournal homepage: www.elsevier.com/locate/atherosclerosishttp://dx.doi.org/10.1016/j.atherosclerosis.2014.11.0110021-9150/© 2014 The Authors. Published by Elsevier Ireland Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/3.0/).Atherosclerosis 238 (2015) 70e76