Tea Consumption Reduces Mild Cognitive Impairment Risk in Community-Dwelling Older Adults via Lowering Interleukin-6: A Mediation Analysis with Propensity Score Matching

Objective To investigate the association between tea consumption and mild cognitive impairment (MCI) among adults aged ≥ 65 years in Shanghai, China, and to examine the potential mediating role of interleukin-6 (IL-6). Methods A cross-sectional study was conducted from March to September 2023, including 272 community-dwelling older adults. Cognitive function was assessed using the Mini-Mental State Examination (MMSE), and participants were classified into MCI (n = 19) and cognitively normal (n = 253) groups according to Petersen's criteria. Propensity score matching (PSM, 2:1) was applied to balance confounders (age and gender), resulting in 57 matched participants (19 MCI, 38 controls). Least Absolute Shrinkage and Selection Operator (LASSO) regression was used to identify key predictors of MCI, and multivariate logistic regression was employed to analyze influencing factors. The mediating effect of IL-6 on the relationship between tea consumption and MCI was tested using bootstrap resampling (5000 repetitions). Results Multivariate logistic regression revealed that regular tea consumption was significantly associated with a reduced risk of MCI ( OR  = 0.137, 95% CI : 0.015–0.786, P  = 0.044). Elevated IL-6 levels were associated with an increased risk of MCI ( OR  = 2.069, 95% CI : 1.217–4.083, P  = 0.016), while vitamin B12 (VB12) levels were inversely associated with MCI risk ( OR  = 0.984, 95% CI : 0.966–0.997, P  = 0.038). Mediation analysis indicated that IL-6 partially mediated the relationship between tea consumption and MCI (ACME = 0.1356, 95% CI : 0.0123–0.3098, P  = 0.022), accounting for 62.51% of the total effect. Conclusion Tea drinking may indirectly reduce the risk of MCI by lowering IL-6 levels, with IL-6 serving as a partial mediator. These findings support a multi-pathway model linking lifestyle, inflammation, and cognition, suggesting that tea consumption and anti-inflammatory interventions may be effective strategies for MCI prevention in older adults.