老年人平均紅血球容積與血小板數量和認知障礙關聯研究

Abstract

背景 台灣人口老化速度為世界第二。隨著人口快速老化，與老化相關的疾病(例如：認知功能障礙)成為重要的健康議題。平均紅血球容積和血小板數量在神經發炎過程中扮演重要的角色。過去只有少部分的研究在探討平均紅血球容積和血小板數量與認知功能障礙研究的關聯性，而且結果並不一致。因此本研究目的在於探討老年人的血液指標(包括平均紅血球容積、血小板數量)和認知功能障礙的關係。 研究設計 本研究為橫斷性研究，於2011至2013年間招募了599位參與台北某三級醫學中心老人健康檢查的65歲以上之老人。每位受試者安排血液檢測並使用蒙特利爾認知評估工具之台灣版來評估認知功能。利用邏輯斯迴歸模型探討血液指標包括平均紅血球容積、血小板數量(連續變項以及四分位數)和認知功能障礙的關係，同時調整了年齡、性別、教育程度、apolipoprotein (APOE) e4遺傳半形以及其他重要的因子。本研究更進一步依性別和APOE e4遺傳半形進行分層分析。 結果 與平均紅血球容積較低的三組四分位數比較，平均紅血球容積最高的四分位數 (MCV> 94.2 fL) 比起其他三組四分位數有1.9倍認知功能障礙的風險(調整後勝算比＝1.90，95%信賴區間= 1.06-3.40)；分層分析後發現以上關係只出現在女性(調整後勝算比＝3.67，95%信賴區間= 1.56-8.60)以及未帶有APOE e4遺傳半形的老年人(調整後勝算比＝1.94，95%信賴區間= 1.01-3.74)。血小板數量較高的三個四分位數 (>169 ×109/L)比起最低的四分位數有顯著降低認知功能障礙的風險(調整後勝算比＝0.41，95%信賴區間= 0.24-0.69)，而此關係在分層分析後只出現在男性(調整後勝算比＝0.27，95%信賴區間= 0.12-0.57)，以及在有APOE e4遺傳半形的老年人身上(調整後勝算比＝0.04，95%信賴區間= 0.006-0.30)。此外性別、年齡及APOE e4遺傳半形與血液指標(包括平均紅血球容積、血小板數量)之間對於認知功能障礙上並無顯著的交互作用。 結論 平均紅血球容積增加與會顯著增加認知功能障礙風險；而血小板數量增加則顯著降低認知功能障礙風險。以上關係依照性別以及是否帶有APOE e4之遺傳半形而不同。需要更多前瞻性且在中國族群的大型研究來證實本研究的發現。

Background Taiwan’s ageing rate ranks the 2nd in the world. As population aging quickly, ageing related health issue, e.g., cognitive impairment becomes an important health concern. Blood mean corpuscular volume (MCV) and platelets (PLT) play a role in neuroinflammation. Few studies explored the association between MCV, platelet count and the risk of cognitive impairment and these studies showed inconsistent results. Therefore, this study was aimed to assess the relationship between MCV, PLT and the risk of cognitive impairment. Materials and Methods This is a cross-sectional study. A total of 599 elderly were recruited from the annual elderly health checkup program of a tertiary medical center in Taipei from 2011 to 2013. Cognitive impairment was assessed by Montreal Cognitive Assessment (MoCA), Taiwanese version. Logistic regression models adjusting for age, gender, education level, APOE e4 status and other potential confounders were utilized to estimate the adjusted odds ratios (AOR) and 95% confidence intervals (95% CI) for the association between MCV or PLT (continuous and quartile variable) and cognitive impairment. Stratification analyses by gender and APOE e4 status were performed for the association above. Results The highest quartile of MCV (> 94.2 fL) was associated with an increased risk of cognitive impairment (AOR = 1.90, 95% CI = 1.06-3.40), which remained significant in women (AOR = 3.67, 95% CI = 1.56-8.60) but not in man. Among APOE e4 non-carriers, high MCV (> 94.2 fL) was associated with an increased risk of cognitive impairment (AOR = 1.94, 95% CI = 1.01-3.74). High PLT (>169 ×109/L) decreased against cognitive impairment (AOR = 0.41, 95% CI = 0.24-0.69), which remained significant only in men (AOR = 0.27, 95% CI = 0.12-0.57). Among APOE e4 carriers, high PLT (>169 ×109/L) protected against the risk of cognitive impairment (AOR = 0.04, 95% CI = 0.006-0.30). No interaction was observed between age, gender or APOE e4 with blood indices (MCV and PLT) on the risk of cognitive impairment. Conclusions High MCV was associated with an increased risk of cognitive impairment and high PLT showed protective effect against cognitive impairment. Significant associations were found between these blood indices and cognitive impairment in some strata after stratified by gender or APOE e4 status. Larger and prospective follow-up studies on Chinese ethic population are warranted to confirm our findings.