Combined impact of neutrophil-to-high-density lipoprotein cholesterol ratio (NHR) and cognitive function on all-cause mortality in older adults: a population-based study

Background The neutrophil-to-high-density lipoprotein cholesterol ratio (NHR) has emerged as a potential biomarker for chronic disease outcomes. Cognitive impairment is a major contributor to mortality in older adults. However, the combined effect of NHR and cognitive function on all-cause mortality remains unclear. This study aims to investigate the joint impact of NHR and cognitive impairment on all-cause mortality in this population. Methods We analyzed participants in the National Health and Nutrition Examination Survey (NHANES) between 2011 and 2014. Participants were grouped according to NHR levels, DSST scores, and the combined NHR and DSST. Weighted Cox regression models assessed the association between NHR, cognitive impairment, and all-cause mortality. Weighted Kaplan-Meier curves estimated survival probabilities. Results The study involved 1,486 participants (weighted sample was 54,078,084) aged 60 years and older, of whom 81.76% (n = 1,180) survived and 18.24% (n = 306) died by the end of follow-up. The median follow-up time was 78 months (IQR: 68-94). Weighted multivariable Cox regression revealed that high NHR (HR = 1.82, 95% CI: 1.21-2.74; P = 0.004), cognitive impairment (HR = 1.87, 95% CI: 1.25-2.79; P = 0.002), and the combination of high NHR and cognitive impairment (HR = 2.98, 95% CI: 1.45-6.14; P = 0.003) were independently associated with higher all-cause mortality, after full adjustment in model 3. Kaplan-Meier curves revealed significant survival differences, with the highest survival rate in the NHR Low & Normal cognition and the lowest in the NHR High & Cognitive impairment (P < 0.001). Conclusions High NHR and cognitive impairment in aged 60 years and older have an increased risk of all-cause mortality. These findings underscore the importance of integrating both NHR and cognitive assessments in mortality risk evaluations, offering a potential strategy for early intervention in aging populations.