In a study conducted in Shanghai, China, researchers have discovered a promising blood biomarker that could aid in the early detection of mild cognitive impairment (MCI), often considered a precursor to Alzheimer's disease (AD). The study, which involved participants from the Heqing Community, has shed light on the potential role of red blood cell distribution width (RDW) in identifying individuals at risk of cognitive decline.

MCI, characterized by subtle cognitive deficits that do not significantly impact daily functioning, affects a substantial portion of the elderly population in China. Epidemiological investigations have shown that the prevalence of MCI among urban Chinese adults aged 60 and 65 is 15.5% and 20%, respectively, with approximately one-third of these individuals progressing to dementia.
The study, led by a team of dedicated physicians, recruited 750 participants aged 65 and above who underwent cognitive assessments using the Montreal Cognitive Assessment (MoCA) and Clinical Dementia Rating (CDR) scales. Among them, 550 individuals voluntarily underwent blood examinations, which revealed a significant association between increased RDW and MCI.
Interestingly, the study also found that female gender and low education levels were risk factors for MCI. This finding aligns with previous evidence suggesting that the sex-specific pathophysiological mechanisms behind AD risk are influenced by the menopause transition, a midlife neuroendocrine transition state unique to females. Additionally, years of education have been linked to the prevalence of MCI in prior studies.
Further analysis of the cognitive domains assessed by MoCA revealed that RDW was negatively correlated with scores in all domains, with the strongest correlation observed for attention. This finding suggests that attention impairment could serve as a sensitive marker for MCI, a notion supported by binary regression analysis showing that impaired attention had the greatest weight among the cognitive domains in MCI.
The study's findings have significant implications for the early detection and management of cognitive impairment. RDW, a readily available and inexpensive hematologic measure, could offer valuable insights into an individual's risk of developing MCI and, potentially, AD. By identifying those at risk early on, healthcare professionals can implement targeted interventions and support strategies to mitigate cognitive decline and improve quality of life.
Reference
Yang, Juan; Sui, Haijing; Song, Haihan; Jiao, Ronghong; Zhao, Xiaohui.
Red Cell Distribution Width is Related to Mild Cognitive Impairment: A Cross-Sectional Study of Community Residents. Neurology India 72(1):p 64-68, Jan–Feb 2024.
DOI: 10.4103/ni.ni_211_22