Associations between neutrophil–lymphocyte ratio and risk of cognitive impairment among Chinese older adults

Associations between the neutrophil–lymphocyte ratio (NLR) and cognitive performance in older population are rarely reported. We investigated the associations between NLR and risk of cognitive impairment in Chinese community-dwelling older adults. Individuals aged ≥ 65 years from the 2011 and 2014 waves of the Chinese Longitudinal Healthy Longevity Survey were enrolled. We used the Chinese version of the Mini-Mental State Examination to evaluate cognitive function, with a score <18 indicating cognitive impairment. NLR was expressed as derived NLR (white blood cell count − lymphocyte count]/lymphocyte count). Logistic regression was used to evaluate the association between NLR levels and risk of cognitive impairment. The study enrolled 2375 cognitively healthy participants and 838 with cognitive impairment. Significantly higher NLR values were noted in the latter than in the former group. In the cross-sectional analysis, NLR values in the highest than in the lowest quartile indicated significantly increased risk of cognitive impairment, after controlling for all confounding factors. During follow-up, 134 of the 1173 healthy participants at baseline developed cognitive impairment. NLR values in the highest two quartiles indicated higher risk of cognitive impairment than those in the lowest quartile. When NLR was classified into dichotomous groups, the risk of cognitive impairment was significantly higher in the high-inflammation than in the noninflammatory status group, regardless of the analysis used (cross-sectional or prospective). Elevated NLR status is associated with increased risk of cognitive impairment in Chinese community-dwelling older adults.