Association and causality between triglycerides and hypertension: evidence from NHANES 2007-2018 and two-sample Mendelian randomisation analysis.

BACKGROUND: Hypertension is a major global health issue, and elevated triglyceride levels may be an independent risk factor. However, existing studies are limited, and the association remains unclear across diverse populations. This study uses the National Health and Nutrition Examination Survey (NHANES) data to investigate this association, supporting hypertension prevention and management strategies. METHODS: Data from NHANES (2007-2018) for adults aged 20 and older were analysed using a weighted multivariable logistic regression to assess the association between triglyceride levels and prevalence of hypertension. Adjusted odds ratios (ORs) with 95% confidence intervals (CIs) were calculated. Restricted cubic splines (RCS) explored the nonlinear associations, and subgroup analyses assessed variable impacts on this association. A two-sample Mendelian randomisation (TSMR) analysis based on genome-wide association study (GWAS) summary data was also conducted to investigate the potential causal relationship between triglyceride levels and hypertension. RESULTS: A total of 14,567 participants were included in this study, among whom 6,428 were diagnosed with hypertension. After full adjustment for all covariates, a significant positive association was observed between triglyceride levels and the prevalence of hypertension (OR: 1.002, 95% CI: 1.001-1.003; P < 0.001). RCS regression analysis further demonstrated a significant nonlinear positive association between triglyceride levels and the prevalence of hypertension (P for non-linearity < 0.001; P for overall < 0.001). Subgroup analysis indicated a significant interaction effect by race (P for interaction < 0.001). Mendelian randomisation (MR) analysis also supported a causal effect of elevated triglyceride levels on increased hypertension risk, with no significant pleiotropy or heterogeneity observed. CONCLUSION: The findings of this study suggest that elevated triglyceride levels are significantly associated with increased prevalence of hypertension, highlighting the potential importance of lipid management in hypertension prevention.