The important effect of 5-HTTLPR polymorphism on the risk of depression in patients with coronary heart disease: a meta-analysis

BACKGROUND: Depression has been recognized as an independent risk factor of coronary heart disease (CHD). Moreover, there is interrelationship of both depression and CHD. However, the potential pathophysiological mechanisms remain unknown. It might be influenced by genetic and environmental factors. According to recent researches, there is potential association between serotonin transporter gene-linked polymorphic region (5-HTTLPR) polymorphism and risk of depression in CHD patients, but the results are still inconclusive. Therefore, we performed this meta-analysis based on unadjusted and adjusted data to ascertain a more precise conclusion. METHODS: We searched relevant articles through PubMed, Embase, Web of Science, Chinese BioMedical Literature (CBM) and Chinese National Knowledge Infrastructure (CNKI) databases up to August 26, 2019. Study selection and data extraction were accomplished by two authors independently. The strength of the correlation was assessed via odds ratios (ORs) with their 95% confidence intervals (95%CIs). RESULTS: This meta-analysis enrolled six observational studies. Based on unadjusted data, there was significant relationship between 5-HTTLPR polymorphism and depression risk in CHD patients under all genetic models (S vs. L: OR = 1.31, 95%CI = 1.07–1.60; SS vs. LL: OR = 1.73, 95%CI = 1.12–2.67; LS vs. LL: OR = 1.47, 95%CI = 1.13–1.92; LS + SS vs. LL: OR = 1.62, 95%CI = 1.25–2.09; SS vs. LL + LS: OR = 1.33, 95%CI = 1.02–1.74). The results of adjusted data further strengthened this relationship (SS vs. LL: OR = 1.89, 95%CI = 1.28–2.80; LS vs. LL: OR = 1.69, 95%CI = 1.14–2.51; LS + SS vs. LL: OR = 1.80, 95%CI = 1.25–2.59). Subgroup analyses based on ethnicity and major depressive disorder revealed similar results to that of the overall analysis. No evidence of publication bias was observed. CONCLUSIONS: Our results suggest that 5-HTTLPR polymorphism may have an important effect on the risk of depression among patients with CHD, and carriers of the S allele of 5-HTTLPR are more vulnerable to depression.