Jarvis M J
ICRF Health Behaviour Unit, National Addiction Centre, London, UK.
Psychopharmacology (Berl). 1993;110(1-2):45-52. doi: 10.1007/BF02246949.
The relationship between habitual coffee and tea consumption and cognitive performance was examined using data from a cross-sectional survey of a representative sample of 9003 British adults (the Health and Lifestyle Survey). Subjects completed tests of simple reaction time, choice reaction time, incidental verbal memory, and visuo-spatial reasoning, in addition to providing self-reports of usual coffee and tea intake. After controlling extensively for potential confounding variables, a dose-response trend to improved performance with higher levels of coffee consumption was observed for all four tests (P < 0.001 in each case). Similar but weaker associations were found for tea consumption, which were significant for simple reaction time (P = 0.02) and visuo-spatial reasoning (P = 0.013). Estimated overall caffeine consumption showed a dose-response relationship to improved cognitive performance (P < 0.001 for each cognitive test, after controlling for confounders). Older people appeared to be more susceptible to the performance-improving effects of caffeine than were younger. The results suggest that tolerance to the performance-enhancing effects of caffeine, if it occurs at all, is incomplete.
利用对9003名英国成年人的代表性样本（健康与生活方式调查）进行横断面调查的数据，研究了习惯性咖啡和茶的摄入量与认知能力之间的关系。除了提供通常咖啡和茶摄入量的自我报告外，受试者还完成了简单反应时间、选择反应时间、附带言语记忆和视觉空间推理测试。在对潜在混杂变量进行广泛控制后，在所有四项测试中均观察到随着咖啡摄入量增加，表现改善的剂量反应趋势（每种情况下P<0.001）。茶的摄入量也发现了类似但较弱的关联，简单反应时间（P=0.02）和视觉空间推理（P=0.013）有显著关联。估计的总体咖啡因摄入量显示出与改善认知能力的剂量反应关系（在控制混杂因素后，每项认知测试的P<0.001）。老年人似乎比年轻人更容易受到咖啡因改善表现的影响。结果表明，对咖啡因增强表现的效果的耐受性（如果确实存在的话）是不完全的。
