Association Between Neutrophil-Lymphocyte Ratio and All-Cause Mortality and Cause-Specific Mortality in US Adults, 1999-2014

Background: Neutrophil-lymphocyte ratio (NLR) is a novel marker of inflammation. Emerging studies have evaluated the relationship of NLR with cardiovascular diseases and malignant conditions. However, rare studies regarded the association between NLR and longterm health status. This study aimed to evaluate the association of NLR with all-cause mortality and cause-specific mortality among adults in the United States. Methods: We obtained eight cycles data of National Health and Nutrition Examination Surveys (NHANES) from 1999 to 2014, and enrolled 32328 participants after certain screening. By weighted chi-square test and linear regression analysis, we analyzed the correlation between NLR and baseline characteristics of the participants. Kaplan-Meier curves and Cox regression models were used to assess the survival relevance of NLR. We conducted stratified analysis, interaction analysis, and sensitivity analysis to robustness of our results. Results: Participants with high NLR levels had a higher risk of death. After adjustment for baseline characteristics, the hazard ratio comparing the higher vs lower NLR levels was 1.43 (95% CI, 1.18-1.73) for all-cause mortality, 1.27 (95% CI, 0.84-1.92) for cancer mortality, and 1.44 (95% CI, 0.96-2.16) for cardiovascular disease mortality. Stratified analysis found that the observed associations between NLR levels and mortality did not differ significantly. Conclusion: In this nationally representative cohort of US adults, higher NLR was significantly associated with an increased risk of all-cause mortality.