Atherosclerosis 205 (2009) 279–283 Contents lists available at ScienceDirect Atherosclerosis journal homepage: www.elsevier.com/locate/atherosclerosis Circulating oxidized LDL levels, current smoking and obesity in postmenopausal women E. Kassi, M. Dalamaga 1 , E. Faviou 1 , G. Hroussalas, K. Kazanis, Ch. Nounopoulos, A. Dionyssiou-Asteriou ∗ Department of Biological Chemistry and Department of Clinical Biochemistry, Medical School, University of Athens, 11 Korinthou Str., 14564 Kifisia, Athens, Greece article info Article history: Received 19 May 2008 Received in revised form 28 October 2008 Accepted 9 November 2008 Available online 18 November 2008 Keywords: Oxidized LDL levels Smoking Obesity Menopause abstract Objective: The aim of the present study was to estimate circulating oxidized low-density lipoprotein (oxLDL) levels in postmenopausal women and evaluate their association with obesity and smoking status. Design and methods: The study included 135 postmenopausal women aged 52–75 years. Forty of them were overweight (BMI 32.4 ± 6.4) and non-smokers (Group A), 40 non-overweight (BMI 22.6 ± 1.8) and smokers (Group B) and 55 non-overweight (BMI 23.5 ± 1.4) and non-smokers (Group C). oxLDL and anti- bodies against them (anti-oxLDL) were measured using ELISA. Serum total cholesterol, LDL, HDL and triglycerides were measured in an automated analyzer. Results: Total cholesterol, LDL, HDL and oxLDL serum levels were significantly elevated in Group A as com- pared to Group B or C, as well as oxLDL in Group B in comparison to Group C (p < 0.001). Triglycerides and anti-oxLDL were increased in Group A in comparison to Group C (p = 0.043 and 0.023). Total cholesterol, LDL, triglycerides and anti-oxLDL did not differ between Groups B and C, while HDL was decreased in Group B as compared to Group C (p <0.001). A significant positive correlation was found between oxLDL and LDL in Group A (r = 0.53, p < 0.001) as well as in Group C (r = 0.955, p ≤ 0.001) and a negative one between oxLDL and HDL in Group C (r = -0.933, p < 0.001). Regression analysis revealed that obesity was a stronger predictor of LDL oxidation than smoking. Conclusions: Postmenopausal obesity is involved in the process of LDL oxidation and appears to be a stronger predictor of LDL oxidation than smoking. Future studies are needed to confirm these associations. © 2008 Elsevier Ireland Ltd. All rights reserved. 1. Introduction Circulating oxidized low-density lipoprotein (oxLDL)-chole- sterol levels are associated with a high risk status of cardiovascu- lar disease [1]. Oxidized LDL is directly involved in the initiation and progression of atherosclerosis [2]. Plasma oxLDL concentra- tion reflects the turnover of oxLDL formed in the vascular wall [3] and elevated oxLDL plasma levels have been shown to be present in patients with coronary artery disease [4–6]. Several risk factors of atherosclerosis such as dyslipidemia, diabetes, inflammation or current smoking have been studied with respect to their possible effects on LDL oxidation [7,8]. The formation of oxLDL is induced by oxidative stress and the determination of oxLDL in serum as well as of autoantibodies against them (anti-oxLDL) have been used as indices of oxidative stress [7,9]. Smoking is involved to the increase of oxidative stress. This involvement is discussed as a potential mechanism for the development of atherosclerosis and the initiation of cardiovascular dysfunction [10]. Moreover elevated ∗ Corresponding author. Tel.: +30 2108077255; fax: +30 2106201294. E-mail address: madalamaga@med.uoa.gr (A. Dionyssiou-Asteriou). 1 These authors have contributed equally to this work. oxLDL serum levels have been found in healthy middle age men and women who were smokers [7]. A high cardiovascular risk characterizes the postmenopausal phase in women [11]. Elevated oxLDL plasma levels were found in postmenopausal women in comparison to fertile women [12]. In postmenopausal women lipid and lipoprotein metabolism is markedly altered [13] as well as fat mass and visceral adiposity [14]. Obesity is also discussed as a cardiovascular risk factor because of its association with a series of metabolic disorders such as diabetes and dyslipidemia [15], oxidative stress [16] and inflammation [17]. Although the reasons for overweight and obesity are multilayered it is well established that menopause is associated with weight gain [14] and hence with increased metabolic risk factors and cardiovas- cular disease [14,18]. A multivariate analysis showed that body mass index (BMI) was one of the most significant predictors of circulat- ing levels of oxLDL [19] probably through leptin that is implicated in the generation of oxidative stress in endothelial cells [20]. There- fore, successful strategies for reducing overweight and improving metabolic risk factors in women are of utmost importance. Intrigued by these observations the present study was con- ducted in overweight and non-overweight postmenopausal women without clinical evidence of cardiovascular disease in order to investigate the association of postmenopausal obesity with circu- 0021-9150/$ – see front matter © 2008 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.atherosclerosis.2008.11.006