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 long-term 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.