Nonlinear associations between the aggregate index of systemic inflammation and cardiovascular disease in adults: evidence from NHANES 2011–2020

Although the connection between inflammation and cardiovascular disease (CVD) is well-documented, the association involving the aggregate index of systemic inflammation (AISI)—a distinctive indicator derived from this formula (neutrophil count × monocyte count × platelet count)/lymphocyte count—has not been extensively explored. Addressing this research gap, our study leveraged the National Health and Nutrition Examination Survey (NHANES) database for investigating a correlation among AISI and CVD among adults in U.S. This investigation provides new insights into the inflammatory mechanisms underlying cardiovascular conditions and may have implications for preventive and therapeutic strategies in cardiovascular health. Our study included 23,472 adults from the 2011–2020 NHANES database. The relationship between AISI and CVD was examined using weighted generalized linear models, subgroup analyses, and threshold effects to estimate effect sizes and saturation effects. Nonlinear relationships between the AISI and CVD were further elucidated through smoothed curve analyses. The prevalence of CVD increases with AISI(P 0.05). Additionally, using threshold effect analysis, we identified a nonlinear relationship across AISI and CVD, with a critical inflection point observed at an index value of 467. Above this threshold, every increment of 100 units within AISI was linked to a 3% elevated CVD prevalence OR = 1.03, 95%CI (1.00, 1.07). Our work substantiates robust evidence for a important positive correlation between AISI and CVD. However, it also highlights the importance of conducting additional prospective research to comprehensively explore the function of AISI in etiology and advancement of CVD.