利用以社區為基礎的世代研究討論 n-6 不飽和脂肪酸與心血管疾病風險的關係

Abstract

背景與目標: 不飽和脂肪酸是生成體內發炎介質重要的前驅物，而許多慢性疾病，例如心血管疾病、第二型糖尿病等等，皆與慢性發炎反應存在著程度不一的關聯。而關於多元不飽和脂肪酸與心血管疾病關係的討論，特別是N-6不飽和脂肪酸對於心血管疾病的作用以及兩者之間是否存在一個劑量反應關係在研究上仍然沒有非常一致的結果。除此之外，多元不飽和脂肪酸代謝途徑中最重要的兩個酵素，Δ5不飽和酶以及Δ6不飽和酶與心血管疾病在以人群研究為基礎的研究仍然缺乏。進一步瞭解血液中的不飽和脂肪酸對於心血管疾病的作用，有助於我們釐清飲食中各類型脂肪酸對於心血管健康的腳色。 方法: 利用一個以社區為基礎的世代研究，1835位 (平均年齡為60.6 ± 10.5 yrs, 女性占44.5%) 有完整利用氣相層析儀分析血液樣本脂肪酸資料的個案，並且排除於研究開始時有心血管疾病病史的個案。 結果: 經過了平均15.9年的追蹤，總共424位個案有心血管疾病的發生。以最高濃度的四分位濃度值比上第一四分位的基準值，N-6不飽和脂肪酸對於心血管疾病的發生風險約降低44%的風險。亞麻油酸對於心血管疾病的發生風險降低約40%。代謝酵素方面，Δ5不飽和酶對於心血管疾病發生風險約降低33% (風險比值= 0.67; 95%信賴區間, 0.50 - 0.91)。Δ5不飽和酶在模型中控制了臨床生化指標及CRP濃度後，保護效果沒有達到顯著。發炎介質對多元不飽和脂肪酸以及代謝酵素對於心血管疾病的作用可能存在影響。並且利用restricted cubic spline討論非線性關係，結果顯示亞麻油酸對於心血管疾病之間並不存在非線性的關係 (P for nonlinearity =0.84; P for trend =0.034) 結論: n-6 不飽和脂肪酸濃度以及Δ5不飽和酶對於心血管疾病存在保護效果，未來進一步深入討論是必要的。

Background: An elevated concentration of long-chain polyunsaturated fatty acid (PUFA), including omega-6 (n-6) linoleic acid (LA) and related effect and dose-response relationship of n-6 PUFA to cardiovascular disease (CVD) risk remains inconsistent. Furthermore, fatty acids metabolic enzymes, including delta-5 desaturase (D5D) and delta-6 desaturase (D6D), were not extensively examined in the population study. Methods: This study design was a community-based prospective cohort, comprising of 1835 participants (60.6 ± 10.5 yrs, 44.5% women) who underwent a comprehensive evaluation of fatty acids in blood using gas chromatography and free from cardiovascular disease at baseline. Results: Overall 424 cases developed cardiovascular events during 15.9 years’ follow-up period. Total n-6 PUFAs were inversely associated with the risk of incident cardiovascular disease, with 44% lower risk (adjusted hazard ratio [HR], 0.56; 95% confidence interval [CI], 0.37 - 0.86; P for trend = 0.002) among the participants in the highest quartile, compared with those in the lowest quartile. Circulating LA was inversely associated with incident CVD, with 40% lower risk (adjusted HR, 0.60; 95% CI, 0.39-0.91; P for trend = 0.017). D5D fatty acids metabolic enzyme activity was inversely associated with incident events (adjusted HR=0.67; 95%CI=0.50 - 0.91; P for trend=0.016), slightly attenuated the effect after adjusted for clinical variables and C-Reactive Protein (CRP). Inflammatory biomarker may attenuate the effects of PUFAs and enzymes. The restricted cubic splines showed no nonlinear relationship between LA and CVD risk. (P for nonlinearity =0.84; P for trend = 0.034). Conclusion: n-6 fatty acids are protective roles for cardiovascular risk. Further studies on n-6 fatty acids and their relationship in health are warranted.