Review Leptin and coronary heart disease: A systematic review and meta-analysis San-Bao Chai a , Feng Sun b, ** , Xiao-Lu Nie b , Jun Wang a, * a Department of Physiology, Capital Medical University, #10 Xi Tou Tiao, You An Men Wai, Feng Tai District, Beijing, PR China b Department of Epidemiology and Bio-Statistics, Peking University Health Science Center, 38 Xueyuan Road, Haidian District, Beijing, PR China article info Article history: Received 17 September 2013 Received in revised form 8 November 2013 Accepted 21 November 2013 Available online 20 December 2013 Keywords: Meta-analysis Coronary heart disease Leptin abstract Introduction: Leptin, an adipose tissue-derived hormone, plays a central role in regulating human energy homeostasis. The role of leptin in regulating blood pressure, activating the sympathetic nervous system, insulin resistance, platelet aggregation, arterial thrombosis, angiogenesis, and inflammatory vascular responses suggests that leptin may have a close relationship with the development of coronary heart disease (CHD). However, no conclusive data are available to determine the association between leptin and CHD. Methods: The PubMed, EMBASE and Cochrane databases were surveyed for original studies describing the association between leptin and CHD outcome from the date of publication of each database through March 2013. The data were extracted by two investigators independently. Results: The meta-analysis reported here was comprised of eight original articles with a total of 21,064 participants (10,842 men, 10,222 women) and 2053 CHD events. The odds ratio for the sociodemographic-adjusted study reported here was 1.57 (95% confidence interval, 1.14e2.16) and 1.72 (95% confidence internal, 1.03e2.87) in males and females, respectively. Further adjustment for addi- tional cardiovascular risk factors resulted in an odds ratio of 1.36 (95% confidence interval, 0.98e1.88) in males and 1.50 (95% confidence interval, 0.93e2.42) in females. Sensitivity analysis restricted to sociodemographics-adjusted studies with high methodological quality indicated an estimate of 1.47 (95% confidence internal, 1.06e2.04) in males and 1.85 (95% confidence internal, 0.61e5.63) in females. Sensitivity analysis restricted to cardiovascular risk factor-adjusted studies showed no significant dif- ferences in both males and females. Conclusion: The results of the meta-analysis represents the most precise and accurate estimate of the relationship between leptin and CHD. Although the associations of leptin and CHD were not statistically significant both in male and female overall, males with high levels of leptin should be paid more attention to. Our findings highlight the need for additional well-designed and gender-specific prospec- tive studies to evaluate the role of leptin on the development of CHD. Ó 2013 Elsevier Ireland Ltd. All rights reserved. Contents 1. Introduction .........................................................................................................................4 2. Methods ............................................................................................................................4 2.1. Literature search .............................................................................................................. 4 2.2. Selection criteria .............................................................................................................. 4 2.3. Data extraction ................................................................................................................ 4 2.4. Data synthesis ................................................................................................................. 4 * Corresponding author. Tel.: þ86 10 8395 0080; fax: þ86 10 8395 0081. ** Corresponding author. Tel./fax: þ86 10 82801191 1055. E-mail addresses: wang_jun@ccmu.edu.cn (J. Wang), sunfeng@bjmu.edu.cn (F. Sun). Contents lists available at ScienceDirect Atherosclerosis journal homepage: www.elsevier.com/locate/atherosclerosis 0021-9150/$ e see front matter Ó 2013 Elsevier Ireland Ltd. All rights reserved. http://dx.doi.org/10.1016/j.atherosclerosis.2013.11.069 Atherosclerosis 233 (2014) 3e10