Associations between dietary and blood inflammatory indices and their effects on cognitive function in elderly Americans

Wanyue Li; Shuna Li; Yaru Shang; Weisheng Zhuang; Guoqiang Yan; Zhuoming Chen; Jun Lyu

doi:10.3389/fnins.2023.1117056

Associations between dietary and blood inflammatory indices and their effects on cognitive function in elderly Americans

Front Neurosci. 2023 Feb 21:17:1117056. doi: 10.3389/fnins.2023.1117056. eCollection 2023.

Authors

Wanyue Li¹, Shuna Li², Yaru Shang¹, Weisheng Zhuang³, Guoqiang Yan¹, Zhuoming Chen¹, Jun Lyu^{2

4}

Affiliations

¹ Department of Rehabilitation, The First Affiliated Hospital of Jinan University, Guangzhou, Guangdong, China.
² Department of Clinical Research, The First Affiliated Hospital of Jinan University, Guangzhou, Guangdong, China.
³ Department of Rehabilitation, Henan Provincial People's Hospital, People's Hospital of Zhengzhou University, Zhengzhou, Henan, China.
⁴ Guangdong Provincial Key Laboratory of Traditional Chinese Medicine Informatization, Guangzhou, Guangdong, China.

Abstract

Objective: To determine the correlations between dietary and blood inflammation indices in elderly Americans and their effects on cognitive function.

Methods: This research extracted data from the 2011-2014 National Health and Nutrition Examination Survey for 2,479 patients who were ≥60 years old. Cognitive function was assessed as a composite cognitive function score (Z-score) calculated from the results of the Consortium to Establish a Registry for Alzheimer's Disease Word Learning and Delayed Recall tests, the Animal Fluency test, and the Digit Symbol Substitution Test. We used a dietary inflammatory index (DII) calculated from 28 food components to represent the dietary inflammation profile. Blood inflammation indicators included the white blood cell count (WBC), neutrophil count (NE), lymphocyte count (Lym), neutrophil-lymphocyte ratio (NLR), platelet-lymphocyte ratio (PLR), neutrophil-albumin ratio (NAR), systemic immune-inflammation index [SII, calculated as (peripheral platelet count) × NE/Lym], and systemic inflammatory response index [SIRI, calculated as (monocyte count) × NE/Lym]. WBC, NE, Lym, NLR, PLR, NAR, SII, SIRI, and DII were initially treated as continuous variables. For logistic regression, WBC, NE, Lym, NLR, PLR, NAR, SII, and SIRI were divided into quartile groups, and DII was divided into tertile groups.

Results: After adjusting for covariates, WBC, NE, NLR, NAR, SII, SIRI, and DII scores were markedly higher in the cognitively impaired group than in the normal group (p < 0.05). DII was negatively correlated with the Z-score when combined with WBC, NE, and NAR (p < 0.05). After adjusting for all covariates, DII was positively correlated with SII in people with cognitive impairment (p < 0.05). Higher DII with NLR, NAR, SII, and SIRI all increased the risk of cognitive impairment (p < 0.05).

Conclusion: DII was positively correlated with blood inflammation indicators, and higher DII and blood inflammation indicators increased the risk of developing cognitive impairment.

Keywords: DII; NHANES; blood inflammation indicators; cognitive function; regression analysis.

Grants and funding

This study was supported by Guangdong Provincial Key Laboratory of Traditional Chinese Medicine Informatization (2021B1212040007), National Key R&D Program of China (2020YFC2005700), and Key Science & Technology Brainstorm Project of Guangzhou (202103000027).