Simultaneous coffee caffeine intake and sleep deprivation alter glucose homeostasis in Iranian men: a randomized crossover trial

Sleep deprivation and coffee caffeine consumption have been shown to affect glucose homeostasis separately, but the combined effects of these two variables are unknown.Forty-two healthy Iranian men, aged 20-40 years old, were assigned to three groups in a randomised crossover trial involving three treatments with two-week washout periods. Subjects were moderate coffee consumers (=3 cups/day), and had a Pittsburgh Sleep Quality Index=5. Each treatment involved three nights of deprived sleep (4 hrs. in bed) plus 3×150 cc/cup of boiled water (BW treatment), decaffeinated coffee (DC treatment, without sugar, 99.9% caffeine-free), and caffeinated coffee (CC treatment, without sugar, 65 mg caffeine/ cup). DC and CC treatments were blinded. At the end of each treatment, fasting serum glucose (using enzyme assays) and insulin (using electrochemiluminescence immunoassay) were measured and, again, two hours after an oral glucose tolerance test (OGTT). Insulin resistance was quantified with the homeostasis model.Repeated measures ANOVA indicated no significant difference between the treatments in fasting serum glucose (p=0.248) or insulin resistance (p=0.079). However, ANOVA demonstrated differences between treatments in fasting serum insulin (p=0.004) and glucose, as well as insulin after OGTT (p0.001). Pairwise comparisons test (within subjects) showed that the CC treatment yielded higher serum glucose and insulin after OGTT (p0.001), higher fasting serum insulin (p=0.001), and increased insulin resistance (p=0.039) as compared to the DC treatment.Thus caffeinated coffee was more adverse for glucose homeostasis compared to decaffeinated coffee in individuals who were simultaneously sleep deprived.背景与目的：睡眠剥夺和咖啡中咖啡因的摄入对葡萄糖稳态的影响已分别被证 明，但这两个变量的综合效果尚不知道。方法与研究设计：42 名年龄在20-40 岁之间的伊朗男性在本随机交叉试验中被分配到3 个试验组，试验组间有两周 的洗脱期。研究对象为中度咖啡消费者（=3 杯/天），并且匹兹堡睡眠质量指 数=5。每种试验包括3 晚上的睡眠剥夺（在床上4 小时），加3 杯开水（BW 试验，每杯150 毫升）、无咖啡因的咖啡（DC 试验，不加糖，99.9%无咖啡 因）或含咖啡因的咖啡（CC 试验，不加糖，每杯含65 毫克咖啡因）。DC 和 CC 处理采用盲法。每种试验结束后，测量空腹血糖（采用酶法测定）和胰岛 素（采用电化学发光免疫分析法测定），口服葡萄糖耐量试验（OGTT）两个 小时后再次测量血糖和胰岛素。胰岛素抵抗采用稳态模型量化。结果：重复测 量方差分析表明各试验组间的空腹血糖（p=0.248）和胰岛素抵抗（p=0.079） 没有显著差异。然而，方差分析表明各试验组间空腹血清胰岛素、血糖和 OGTT 后的胰岛素有差异。配对比较（研究对象间）表明：与DC 试验组相 比，CC 试验组OGTT 后血糖和胰岛素较高（p0.001），空腹血清胰岛素 （p=0.001）和胰岛素抵抗（p=0.039）也增加。结论：对睡眠被剥夺的人，含 咖啡因的咖啡比不含咖啡因的咖啡更不利于葡萄糖稳态。.