Leptin concentration and risk of coronary heart disease and stroke: A systematic review and meta-analysis

Background and purposeAlthough high leptin concentration has been shown to be correlated with established vascular risk factors, epidemiologic studies have reported inconclusive results on the association between leptin and cardiovascular diseases (CVD). Therefore, a meta-analysis was performed to evaluate this issue.MethodsWe searched Pubmed, Embase, and the Cochrane Library from their inception to Jan 2016 for both case-control and cohort studies that assessed leptin concentration and CVD risk. Reports with odds ratio (OR), risk ratio (RR) and corresponding 95% confidence intervals (CI) were considered. The data were extracted by two investigators independently.ResultsA total of 13 epidemiologic studies totaling 4257 CVD patients and 26710 controls were included. A significant inverse association was shown between leptin and coronary heart disease (CHD), with an overall OR of 1.16 (95% CI: 1.02–1.32), but not for stroke (OR = 1.21, 95% CI 0.98–1.48) under sociodemographic adjustment. Further adjustment for additional cardiovascular risk factors resulted in ORs of 1.16 (95% CI 0.97–1.40) for CHD and 1.10 (95% CI 0.89–1.35) for stroke. The findings remained when analyses were restricted to high-quality studies and indicated OR estimates of 1.07 (95% CI 0.96–1.19) for CHD and 0.98 (95% CI 0.76–1.25) for stroke. In a subgroup meta-analysis, a high leptin level was not independently associated with CHD in both females (OR = 1.03, 95% CI 0.86–1.23) and males (OR = 1.09, 95% CI 0.95–1.26) or with stroke in both females (OR = 1.13, 95% CI 0.87–1.47) and males (OR = 0.80, 95% CI 0.59–1.09). There was no significant publication bias as suggested by Egger test outcomes.ConclusionsOur findings indicate that high leptin levels may not be associated with risks of CHD and stroke. Further large, well-designed prospective cohort studies are needed to fully evaluate the role of leptin on the risk of CVD.

背景与目的
尽管已有研究证实瘦素浓度升高与已明确的血管危险因素相关，但现有流行病学研究关于瘦素与心血管疾病（CVD）的关联尚未得出一致性结论。因此，本研究开展一项荟萃分析以探讨该问题。
研究方法
我们检索了PubMed、Embase及Cochrane图书馆自建库至2016年1月的相关文献，纳入评估瘦素浓度与CVD风险的病例对照研究及队列研究，筛选报道比值比（OR）、相对危险度（RR）及其对应95%置信区间（CI）的研究。由两名研究者独立提取数据。
研究结果
最终共纳入13项流行病学研究，涉及4257名CVD患者及26710名对照。在社会人口学因素校正后，瘦素与冠心病（CHD）存在显著负相关，合并比值比（OR）为1.16（95%CI：1.02~1.32），但未观察到瘦素与卒中存在显著关联（OR=1.21，95%CI：0.98~1.48）。进一步校正其他心血管危险因素后，冠心病的合并OR值为1.16（95%CI：0.97~1.40），卒中的合并OR值为1.10（95%CI：0.89~1.35）。当仅纳入高质量研究进行分析时，上述结果仍保持稳定：冠心病的OR估计值为1.07（95%CI：0.96~1.19），卒中的OR估计值为0.98（95%CI：0.76~1.25）。亚组荟萃分析结果显示，无论女性（OR=1.03，95%CI：0.86~1.23）还是男性（OR=1.09，95%CI：0.95~1.26）群体，高瘦素水平均未与冠心病独立相关；在卒中方面，女性（OR=1.13，95%CI：0.87~1.47）与男性（OR=0.80，95%CI：0.59~1.09）群体亦未观察到显著关联。Egger检验结果提示不存在显著的发表偏倚。
研究结论
本研究结果表明，高瘦素水平可能与冠心病及卒中的发病风险无显著关联。未来仍需开展大规模、设计严谨的前瞻性队列研究，以全面评估瘦素在心血管疾病（CVD）发病风险中的作用。