Correlation of advanced lung cancer inflammation index with all-cause, cardiovascular, and cancer mortality in individuals with metabolic syndrome: Evidence from NHANES 2007–2018

Metabolic syndrome is associated with persistent low-grade inflammation. The advanced lung cancer inflammation index (ALI) is a comprehensive index that measures inflammation. The purpose of this study was to determine the relationship between ALI and all-cause, cardiovascular, and cancer mortality in a metabolic syndrome (MetS) population. We extracted cohort data from the 2007-2018 National Health and Nutrition Examination Survey for analysis. Weighted Kaplan-Meier analyses and multivariate adjusted Cox analyses were employed to evaluate the association between ALI and mortality due to all causes, cardiovascular diseases, and cancer in individuals with MetS. Nonlinear relationships were assessed using restricted cubic spline analysis. Subgroup and interaction analyses were conducted to enhance result robustness. This study enrolled 3110 participants, with 366 deaths from all-cause, 92 deaths due to cardiovascular diseases, and 98 deaths related to cancer during the 81-month follow-up period. The population was stratified into 4 groups based on ALI quartiles. After adjusting for covariates, the analysis revealed a significantly reduced risk of all-cause mortality in (Q2, Q3), and Q4 group compared to the reference group (Q1). Similarly, a decreased risk of cardiovascular disease mortality was observed in association with ALI in Q2 and Q3 group compared to the reference group. Stratified analyses further show the robustness of these relationships. In addition, this research also reveals that in the MetS population ≥ 60 years of age, Q2 group is associated with a lower risk of cancer mortality than Q1 group. The restricted cubic spline analyses further revealed a nonlinear association between ALI and all-cause mortality in the MetS population, while demonstrating a linear association with cardiovascular mortality and cancer mortality. ALI is a reliable biomarker of systemic inflammation in the MetS population. In individuals with MetS, reduced levels of ALI are strongly associated with an increased risk of all-cause and cardiovascular mortality, as well as increased cancer mortality in those aged > 60 years.