Sievenpiper J L, Jenkins D J, Josse R G, Vuksan V
Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Ont.
CMAJ. 2000 Apr 4;162(7):993-6.
Dilution has been noticed to increase the glycemic response to various sugars, including glucose. This effect may contribute to the poor reproducibility of the oral glucose tolerance test (OGTT). To test this hypothesis we assessed the effect of diluting a 75-g OGTT on 2-hour postprandial blood glucose based diagnostic outcomes, incremental glycemia and area under the glucose curve.
On 3 different occasions, 10 subjects (mean age 40 [and standard error of the mean (SEM) 3.2] years; mean body mass index 27.2 [and SEM 1.2] kg/m2) without previously diagnosed dysglycemia were given a 300-mL, 600-mL or 900-mL 75-g OGTT in random order. The protocol followed the American Diabetes Association's guidelines. Finger-prick capillary blood samples were obtained at fasting and then 15, 30, 45, 60, 90 and 120 minutes after the start of the test.
At 30, 45 and 60 minutes, incremental glycemic concentrations were significantly higher with the 900-mL meal (means [and SEMs]: 4.9 [0.4] mmol/L, 5.1 [0.6] mmol/L and 4.6 [0.8] mmol/L, respectively) than with the 600-mL (means [and SEMs]: 4.0 [0.3] mmol/L, 4.2 [0.6] mmol/L and 3.6 [0.7] mmol/L, respectively) and the 300-mL meals (means and [SEMs]: 3.8 [0.5] mmol/L, 4.0 [0.5] mmol/L and 3.2 [0.6] mmol/L, respectively) (p < 0.05). The same was true for peak incremental blood glucose, regardless of time (p < 0.05). The area under the curve for the 900-mL meal (mean [and SEM] 404 [57] min.mmol/L) was significantly higher than for the 600-mL (mean [and SEM] 331 [51] min.mmol/L) and 300-mL meals (mean [and SEM] 280 [48] min.mmol/L) (p < 0.05). No other significant differences were observed.
Dilution of the 75-g OGTT will likely not affect current screening practices that use 2-h postprandial glucose levels as the basis for diagnosis. It may, however, bias the interpretation of older criteria that rely on intermediate time points because these midpoints appear to be sensitive to alterations in the total volume of the meal ingested.
人们已经注意到稀释会增强对包括葡萄糖在内的各种糖类的血糖反应。这种效应可能导致口服葡萄糖耐量试验（OGTT）的重复性较差。为了验证这一假设，我们评估了将75克OGTT稀释后对基于餐后2小时血糖的诊断结果、血糖增量以及葡萄糖曲线下面积的影响。
在3个不同的时间段，10名之前未被诊断出血糖异常的受试者（平均年龄40岁[平均标准误（SEM）3.2岁]；平均体重指数27.2[SEM 1.2]kg/m²）被随机给予300毫升、600毫升或900毫升的75克OGTT。该方案遵循美国糖尿病协会的指南。在空腹时以及试验开始后15、30、45、60、90和120分钟采集手指针刺毛细血管血样。
在30、45和60分钟时，900毫升餐食的血糖增量浓度（平均值[和标准误]：分别为4.9[0.4]mmol/L、5.1[0.6]mmol/L和4.6[0.8]mmol/L）显著高于600毫升餐食（平均值[和标准误]：分别为4.0[0.3]mmol/L、4.2[0.6]mmol/L和3.6[0.7]mmol/L）和300毫升餐食（平均值[和标准误]：分别为3.8[0.5]mmol/L、4.0[0.5]mmol/L和3.2[0.6]mmol/L）（p<0.05）。无论时间如何，峰值血糖增量情况也是如此（p<0.05）。900毫升餐食的曲线下面积（平均值[和标准误]404[57]min.mmol/L）显著高于600毫升餐食（平均值[和标准误]331[51]min.mmol/L）和300毫升餐食（平均值[和标准误]280[48]min.mmol/L）（p<0.05）。未观察到其他显著差异。
75克OGTT的稀释可能不会影响目前以餐后2小时血糖水平作为诊断依据的筛查方法。然而，对于依赖中间时间点的旧标准的解读可能会产生偏差，因为这些中间点似乎对摄入餐食的总体积变化敏感。
