Leptin and coronary heart disease: A systematic review and meta-analysis

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, 1.14-2.16) and 1.72 (95% confidence internal, 1.03-2.87) in males and females, respectively. Further adjustment for additional cardiovascular risk factors resulted in an odds ratio of 1.36 (95% confidence interval, 0.98-1.88) in males and 1.50 (95% confidence interval, 0.93-2.42) in females. Sensitivity analysis restricted to sociodemographics-adjusted studies with high methodological quality indicated an estimate of 1.47 (95% confidence internal, 1.06-2.04) in males and 1.85 (95% confidence internal, 0.61-5.63) in females. Sensitivity analysis restricted to cardiovascular risk factor-adjusted studies showed no significant differences 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 prospective studies to evaluate the role of leptin on the development of CHD. (C) 2013 Elsevier Ireland Ltd. All rights reserved.