Systemic immune-inflammation index and uric acid mediate the association between obesity and hypertension in young and middleaged adults

Increasing evidence confirms that obesity, inflammation, and uric acid (UA) are important hypertension risk factors. However, the interplay among these factors in hypertension remains unclear. We explored this intricate relationship in young and middle-aged adults using data from the National Health and Nutrition Examination Survey (2011-2018). We analyzed the associations between obesity indicators, including weight-adjusted waist index (WWI), fat mass index (FMI), and visceral adiposity index (VAI) and hypertension, considering mediating roles of the systemic immune-inflammation index (SII) and UA. We included 5,166 participants aged 18-59 years, and 1,154 (22.34%) experienced hypertension. Patients with hypertension exhibited significantly elevated SII, UA, and obesity indicators than did those without hypertension (p < 0.001). Weighted logistic regression analysis revealed a positive correlation between WWI, FMI, VAI, and hypertension risk, with significant dose-response and nonlinear associations. SII and UA partially mediated the association between WWI and FMI with hypertension, with UA also mediating the VAI-hypertension link. Subgroup analyses indicated that the association between WWI, FMI, VAI, and hypertension was significant in most subgroups. Our findings highlight the strong association between obesity indicators and hypertension and underscore the importance of targeting inflammation and UA levels in managing hypertension risk among young and middle-aged adults.