Carr A B, Einstein R, Lai L Y, Martin N G, Starmer G A
Acta Genet Med Gemellol (Roma). 1981;30(4):249-55. doi: 10.1017/s0001566000006450.
Self-reported cold data have been analyzed for 95 pairs of identical twins aged 14-64 who took part in a double-blind trial of vitamin C tablets. One member of each twin pair took a tablet containing 1 g vitamin C and the other took a well-matched placebo each day for 100 days. In the total sample there was no effect of vitamin C in preventing colds. However, subdivision of the data showed a significant preventive effect of the placebo in the 51 pairs living together and an equal and opposite preventive effect of the vitamin C in the 44 pairs living apart. The placebo effect in the pairs living together may be attributed to the large proportion who wrongly perceived which treatment they were taking. The reduction of colds in the vitamin C group of the pairs living apart was about 20%. There were significant correlations between cold symptoms reported and the personality trait of neuroticism. No side effects of substantive changes in serum biochemistry could be attributed to the vitamin C dose.
对95对年龄在14至64岁之间参与维生素C片双盲试验的同卵双胞胎的自我报告感冒数据进行了分析。每对双胞胎中的一人每天服用一片含1克维生素C的药片，另一人则服用匹配良好的安慰剂，持续100天。在整个样本中，维生素C对预防感冒没有效果。然而，对数据进行细分后发现，对于51对住在一起的双胞胎，安慰剂有显著的预防作用；而对于44对分开居住的双胞胎，维生素C有同等且相反的预防作用。住在一起的双胞胎中出现的安慰剂效应可能是由于很大一部分人错误地感知了自己所服用的治疗方法。分开居住的双胞胎中，维生素C组的感冒减少率约为20%。报告的感冒症状与神经质人格特质之间存在显著相关性。血清生化的实质性变化未发现可归因于维生素C剂量的副作用。
