%0 Journal Article %T Serum Lipid Profiles and Cancer Risk in the Context of Obesity: Four Meta-Analyses %A Jennifer C. Melvin %A Lars Holmberg %A Sabine Rohrmann %A Massimo Loda %A Mieke Van Hemelrijck %J Journal of Cancer Epidemiology %D 2013 %I Hindawi Publishing Corporation %R 10.1155/2013/823849 %X The objective here was to summarize the evidence for, and quantify the link between, serum markers of lipid metabolism and risk of obesity-related cancers. PubMed and Embase were searched using predefined inclusion criteria to conduct meta-analyses on the association between serum levels of TG, TC, HDL, ApoA-I, and risk of 11 obesity-related cancers. Pooled relative risks (RRs) and 95% confidence intervals were estimated using random-effects analyses. 28 studies were included. Associations between abnormal lipid components and risk of obesity-related cancers when using clinical cutpoints ( ; ; ; ) were apparent in all models. RRs were 1.18 (95% CI: 1.08每1.29) for TC, 1.20 (1.07每1.35) for TG, 1.15 (1.01每1.32) for HDL, and 1.42 (1.17每1.74) for ApoA-I. High levels of TC and TG, as well as low levels of HDL and ApoA-I, were consistently associated with increased risk of obesity-related cancers. The modest RRs suggest serum lipids to be associated with the risk of cancer, but indicate it is likely that other markers of the metabolism and/or lifestyle factors may also be involved. Future intervention studies involving lifestyle modification would provide insight into the potential biological role of lipid metabolism in tumorigenesis. 1. Introduction Obesity is a major worldwide problem, over 30% of adults in Western populations are obese, and there is growing evidence of the associated health risks associated [1每5]. The link between obesity and cancer risk has been studied extensively, but the results of individual studies do not suggest a consistent association [1, 6, 7]. Common cancers studied in the context of obesity include colorectal, breast, prostate, endometrial, pancreatic, liver, ovarian, kidney, gallbladder, leukaemia, and oesophageal cancers [4, 7每17]. The underlying mechanisms of action are not clear [1, 18每20]. A solid understanding could translate directly to patient benefit through implementation of therapeutic strategies to reduce cancer risk and mortality [19]. Assuming that the lipid metabolism plays a role in the biological processes driving the development of cancer, this could be easily modified by existing methods such as exercise, medication, or diet. Increased physical activity levels improve cardiovascular and overall mortality in healthy populations [21每24]. Also, physical activity after cancer diagnosis is associated with improvements in cancer outcomes [25, 26] and metabolic markers such as cholesterol [27, 28]. As such, improvements in lipid levels through uptake of physical activity may also translate into improvements in %U http://www.hindawi.com/journals/jce/2013/823849/