Aging Cell (2007) 6, pp639–647 Doi: 10.1111/j.1474-9726.2007.00321.x © 2007 The Authors 639 Journal compilation © Blackwell Publishing Ltd/Anatomical Society of Great Britain and Ireland 2007 Blackwell Publishing Ltd Telomere length and cardiovascular risk factors in a middle-aged population free of overt cardiovascular disease Sofie Bekaert, 1 Tim De Meyer, 1 Ernst R. Rietzschel, 2 Marc L. De Buyzere, 2 Dirk De Bacquer, 3 Michel Langlois, 4 Patrick Segers, 5 Luc Cooman, 6 Piet Van Damme, 6 Peter Cassiman, 6 Wim Van Criekinge, 1 Pascal Verdonck, 5 Guy G. De Backer, 3 Thierry C. Gillebert, 2 Patrick Van Oostveldt, 1 on behalf of the Asklepios investigators 1 Department of Molecular Biotechnology, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, B-9000 Ghent, Belgium Departments of 2 Cardiovascular Diseases, 3 Public Health, Ghent University Hospital, De Pintelaan 185, B-9000 Ghent, Belgium 4 Department of Clinical Chemistry, AZ St-Jan AV Hospital, Ruddershove 10, B-8000 Bruges, Belgium 5 Cardiovascular Mechanics and Biofluid Dynamics Research Unit, Institute Biomedical Technology, Faculty of Engineering, Ghent University, St-Pietersnieuwstraat 41, B-9000 Ghent, Belgium 6 Association of Primary Care Physicians Asklepios V.O.F., Terbekenstraat 40, B-9320 Nieuwerkerken-Aalst, Belgium Summary Evidence assembled over the last decade shows that aver- age telomere length (TL) acts as a biomarker for biological aging and cardiovascular disease (CVD) in particular. Although essential for a more profound understanding of the underlying mechanisms, little reference information is available on TL. We therefore sought to provide base- line TL information and assess the association of preva- lent CVD risk factors with TL in subjects free of overt CVD within a small age range. We measured mean telomere restriction fragment length of peripheral blood leuko- cytes in a large, representative Asklepios study cohort of 2509 community-dwelling, Caucasian female and male volunteers aged approximately 35–55 years and free of overt CVD. We found a manifest age-dependent telomere attrition, at a significantly faster rate in men as compared to women. No significant associations were established with classical CVD risk factors such as cholesterol status and blood pressure, yet shorter TL was associated with increased levels of several inflammation and oxidative stress markers. Importantly, shorter telomere length was associated with an increasingly unhealthy lifestyle, particularly in men. All findings were age and gender adjusted where appropriate. With these cross-sectional results we show that TL of peripheral blood leukocytes primarily reflects the burden of increased oxidative stress and inflammation, whether or not determined by an increasingly unhealthy lifestyle, while the association with classical CVD risk factors is limited. This further clarifies the added value of TL as a biomarker for bio- logical aging and might improve our understanding of how TL is associated with CVD. Key words: aging; cardiovascular disease; inflammation; lifestyle; oxidative stress; telomere. Introduction The length of telomeres, the specialized terminal regions of chromosomes, from circulating peripheral blood leukocytes (PBL) has been proposed as a systemic index of biological aging. Human telomeres consist of tandem repeats of a noncoding TTAGGG hexamer (Blackburn, 2000). Telomere length (TL) is to a large extent genetically determined, yet in proliferating cells telomeric sequences are lost with each cell division due to the inability of DNA polymerase to complete the chromosome ter- mini, which is reflected in an age-dependent telomere attrition (Lindsey et al., 1991; Blackburn, 2000; Graakjaer et al., 2006). In addition, in vitro experiments showed TL to be further modulated by environmental factors such as oxidative stress that induces direct DNA damage to the telomeric DNA (von Zglinicki et al., 1995). Furthermore, epidemiological results suggest that oxidative stress may be involved in in vivo telomere attrition (Demissie et al., 2006). TL might therefore offer a valuable tool to measure biological aging and could in particular represent a helpful biomarker in cardiovascular disease (CVD) risk stratification, as CVD is considered as a typical aging disease (Bekaert et al., 2005a). In recent studies, telomere length was suggested to be associated with CVD and risk. Shorter telomeres were, for example, demonstrated in subjects who smoked (Nawrot et al., 2004; Valdes et al., 2005), had elevated pulse pressure (Jeanclos et al., 2000; Benetos et al., 2001), diabetes (Jeanclos et al., 1998), premature myocardial infarction (Brouilette et al., 2003), Correspondence Sofie Bekaert, PhD, Department of Molecular Biotechnology, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, B-9000 Ghent, Belgium. Tel.: +32 9 264 99 12; fax: +32 9 264 62 19; e-mail: sofie.bekaert@UGent.be Accepted for publication 21 May 2007 Sofie Bekaert, Tim De Meyer, Ernst R. Rietzschel, and Marc L. De Buyzere contributed equally to the article.