咖啡因可能避開停經後女性的第二型糖尿病


  【24drs.com】根據發表在一月號糖尿病照護期刊的研究結果,增加攝取咖啡因與停經後女性第二型糖尿病風險較低有關,且性荷爾蒙結合球蛋白(sex hormone–binding globulin,SHBG)可能與此有關。
  
  咖啡因可能透過活化能量代謝與加強胰島素敏感性及β細胞功能來增加葡萄糖耐受性。過去研究將咖啡因攝取量以及性荷爾蒙血漿濃度或SHBG之間相連,其他研究則顯示,性荷爾蒙在第二型糖尿病上有其角色。另外,其他研究證實SHBG濃度與第二型糖尿病風險成反比的關係。
  
  然而,目前並沒有研究針對攝取咖啡因、性荷爾蒙以及SHBG、第二型糖尿病風險之間進行整體的研究。加州大學洛杉磯分校公共衛生研究所流行病學博士生Atsushi Goto與同事們寫到,咖啡因攝取已經證實與第二型糖尿病風險下降有關,但是其機轉大部分仍然未知。我們想要檢驗性荷爾蒙濃度以及SHBG是否可能解釋咖啡因攝取與第二型糖尿病之間的反向關係。
  
  研究人員進行了一項來自前瞻性女性健康研究數據的病例控制研究,這項研究收納平均追蹤10年的359位停經後新診斷第二型糖尿病患者,這些受試者與年齡、種族、追蹤時間、還有抽血時間相符合的359位控制受試者進行比較。
  
  研究人員發現攝取咖啡因與SHBG之間有正向關係,但與性荷爾蒙無關。每天喝至少4杯咖啡因咖啡女性的變項校正SHBG幾何平均數為26.6nmol/L,沒有喝咖啡的女性為23.0 nmol/L(P=0.01);去咖啡因咖啡或茶與SHBG之間沒有關係,去咖啡因咖啡或茶與性荷爾蒙之間也沒有關係。
  
  每天至少喝4杯咖啡因咖啡的女性,相較於不喝的受試者,發生第二型糖尿病的多變項校正勝算比(OR)為0.47(95%信賴區間[CI]為0.23-0.94;P=0.047);校正SHBG後降低關連性,使得統計上未達顯著差異(OR為0.71;95% CI為0.31-0.61;P=0.47)。
  
  這項研究限制包括斷面性分析、因為未測量或不完整測量共變項可能的影響、飲食測量與生物標記錯誤分類的可能性(例如來自使用存放樣本的錯誤),以及因為研究的族群是停經後女性而無法推廣到停經前女性或男性。
  
  作者們解釋,SHBG影響相對大量的性荷爾蒙,因為其與雄性激素有高親和力,而與雌性激素的親和力低。許多細胞都有SHBG受體,這在固醇訊息傳遞系統扮演重要角色。
  
  咖啡的許多成分,包括咖啡因、咖啡固醇、以及咖啡豆醇可能影響肝臟酵素的活性,這可能進而影響肝臟中SHBG的合成與代謝。
  
  這項研究發現,飲用去咖啡因咖啡的人們,SHBG血漿濃度比飲用咖啡因咖啡者低,這代表咖啡因是影響SHBG以及降低第二型糖尿病風險最重要的成分。
  
  作者們的結論是,其研究結果顯示,SHBG濃度可能解釋了停經後女性喝咖啡的習慣具有對抗第二型糖尿病風險保護作用的潛力。但是,這仍有代觀察性與實驗性研究進一步了解其中的機轉。
  
  這項研究由國家衛生研究院、伯勒斯惠康基金會贊助。其中一位作者由國家糖尿病與消化及腎臟疾病機構資助,另一位作者由國家人類基因體研究機構與加州大學洛杉磯分校伯勒斯惠康基金會預防代謝疾病校內計畫贊助。作者們表示沒有相關資金上的往來。

Caffeine May Ward Off Type 2 Diabetes in Postmenopausal Women

By Jim Kling
Medscape Medical News

February 4, 2011 — Increases in caffeinated coffee consumption are associated with lower type 2 diabetes risk among postmenopausal women, and sex hormone–binding globulin (SHBG) may be responsible for the relationship, according to research published in the January issue of Diabetes.

Coffee may raise glucose tolerance by activating energy metabolism and boosting insulin sensitivity and β-cell function. Previous research has linked coffee intake with plasma levels of sex hormones or SHBG, and other research suggests that sex hormones play a role in the development of type 2 diabetes. Other studies have shown an inverse relationship between SHBG level and risk of type 2 diabetes.

However, no studies have looked at the whole picture of coffee consumption, sex hormones and SHBG, and risk for type 2 diabetes. "Coffee consumption has been inversely associated with type 2 diabetes risk, but its mechanisms are largely unknown," write Atsushi Goto, a doctoral student of epidemiology from the University of California–Los Angeles School of Public Health and colleagues, "We aimed to examine whether plasma levels of sex hormones and [SHBG] may account for the inverse association between coffee consumption and type 2 diabetes risk."

The researchers conducted a case-control study derived from the prospective Women's Health Study. The study included a median follow-up of 10 years and included 359 postmenopausal women with newly diagnosed type 2 diabetes, who were matched with 359 control participants by age, race, duration of follow-up, and time of blood draw.

The researchers found a positive association between intake of caffeinated coffee and SHBG, but no association with sex hormones. The multivariable-adjusted geometric mean of SHBG plasma levels among women drinking at least 4 cups of caffeinated coffee a day was 26.6 nmol/L. Among nondrinkers, the value was 23.0 nmol/L (P = .01). There were no associations between decaffeinated coffee or tea and SHBG, nor was there an association between decaffeinated coffee or tea and sex hormones.

For women who drank at least 4 cups of caffeinated coffee per day, the multivariable-adjusted odds ratio (OR) of type 2 diabetes compared with nondrinkers was 0.47 (95% confidence interval [CI], 0.23 - 0.94; P = .047). Adjustment for SHBG reduced caused the association to lose statistical significance (OR, 0.71; 95% CI, 0.31 - 1.61; P = .47).

Study limitations include use of cross-sectional analysis, possible confounding from unmeasured or incompletely measured covariates, potential for misclassifications of dietary measures and biomarkers (eg, from, use of stored samples), and inability to generalize to premenopausal women or men because the population studied was postmenopausal women.

SHBG influences the relative abundance of sex hormones because it binds androgens with high affinity and binds to estrogens with low affinity, the authors explain. SHBG receptors are found on a variety of cells, and it plays an important role in the steroid-signaling system.

Several components of coffee, including caffeine, cafestol, and kahweol, may affect the activity of liver enzymes, which may in turn influence the synthesis and metabolism of SHBG in the liver.

The study found lower plasma values of SHBG in drinkers of decaffeinated coffee than in drinkers of caffeinated coffee, which suggests that caffeine may be the most important constituent of coffee for affecting SHBG and for reducing type 2 diabetes.

The authors conclude: "[O]ur results suggest that SHBG levels may account for the potential protective effect of habitual coffee consumption against type 2 diabetes risk among postmenopausal women. A better understanding of the underlying mechanisms requires further investigation in both observational and experimental settings."

The study was supported by the National Institutes of Health and the Burroughs Wellcome Fund. One study author is supported by a grant from the National Institute of Diabetes and Digestive and Kidney Diseases, and another is supported by a grant from the National Human Genome Research Institute and the University of California–Los Angeles-Burroughs Wellcome Fund Interschool Program on Metabolic Diseases Prevention. The authors have disclosed no relevant financial relationships.

Diabetes. 2011; 60:269-275.

    
相關報導
單靠篩檢與治療無法預防第二型糖尿病
2017/1/12 上午 11:07:07
大麻衍生製劑可能有助於第二型糖尿病
2016/9/21 下午 03:39:06
患者的伴侶一起參與、改善糖尿病控制
2016/8/12 下午 06:02:54

上一頁
   1   2   3   4   5   6   7   8   9   10  




回上一頁