The association between joint Serum Neurofilament Light Chain and type 2 diabetes with all-cause and cardiovascular mortality in US adults: a longitudinal study of NHANES.

Background: In the past, there has been a clear conclusion regarding the sole impact of serum neurofilament light chain (sNfL) levels or type 2 diabetes mellitus (DM) on the risk of death. However, the combined effect of sNfL levels and type 2 DM on all-cause and cardiovascular mortality is still uncertain.

Methods: This study was a prospective cohort study based on data from the National Health and Nutrition Examination Survey (NHANES). The sNfL levels were measured through immunological methods using blood samples collected during the survey. The diagnosis of diabetes was based on rigorous criteria, and participants' mortality data were followed up until December 31, 2019. Firstly, we separately examined the effects of sNfL and type 2 DM on all-cause and cardiovascular mortality, and finally studied the comprehensive impact of the combination of sNfL and type 2 DM on the risk of mortality. Cumulative Kaplan-Meier curves, multivariate logistic regression and sensitivity analysis were incorporated throughout the entire study.

Results: Participants in the highest quartile of sNfL were observed. Multivariable COX regression model showed that increased sNfL levels and type 2 DM were respectively associated with an increased risk of all-cause and cardiovascular mortality. Furthermore, elevated sNfL levels were significantly associated with an increased risk of all-cause mortality and cardiovascular mortality after adjustment for confounding factors. When considering both elevated sNfL levels and type 2 DM, individuals had a significantly increased risk of mortality. Sensitivity analysis confirmed the robustness of the findings.

Conclusions: These results suggest that elevated levels of sNfL and type 2 DM are associated with an increased risk of all-cause and cardiovascular mortality, and that participants with increased sNfL levels associated with type 2 DM have higher all-cause mortality and cardiovascular mortality.