Department of Psychology, University of Edinburgh, 7 George Square, Edinburgh EH8 9JZ, UK.
Int Psychogeriatr. 2013 Sep;25(9):1393-407. doi: 10.1017/S1041610213000793. Epub 2013 Jun 4.
Evidence from observational studies to date suggests that healthy dietary patterns are associated with better cognitive performance in later life. We examined the extent to which childhood intelligence quotient (IQ) and socioeconomic status account for this association.
Analyses were carried out on 882 participants in the Lothian Birth Cohort 1936 Study. Four dietary patterns were extracted using principal components analysis of a food frequency questionnaire, namely "Mediterranean-style," "health aware," "traditional," and "sweet foods." Cognitive function was assessed at the age of 70 years, including general (g) cognitive ability, processing speed, memory, and verbal ability.
Before adjustment for childhood IQ and socioeconomic status, the "Mediterranean-style" dietary pattern was associated with significantly better cognitive performance (effect size as partial eta-square (ηp(2)) range = 0.005 to 0.055), and the "traditional" dietary pattern was associated with poorer performance on all cognitive domains measured in old age (ηp(2) = 0.009 to 0.103). After adjustment for childhood IQ (measured at the age of 11 years) and socioeconomic status, statistical significance was lost for most associations, with the exception of verbal ability and the "Mediterranean-style" pattern (National Adult Reading Test (NART) ηp(2) = 0.006 and Wechsler Test of Adult Reading (WTAR) ηp(2) = 0.013), and the "traditional" pattern (NART ηp(2) = 0.035 and WTAR ηp(2) = 0.027).
Our results suggest a pattern of reverse causation or confounding; a higher childhood cognitive ability (and adult socioeconomic status) predicts adherence to a "healthy" diet and better cognitive performance in old age. Our models show no direct link between diet and cognitive performance in old age; instead they are related via the lifelong-stable trait of intelligence.
迄今为止，来自观察性研究的证据表明，健康的饮食模式与晚年更好的认知表现有关。我们研究了儿童智商 (IQ) 和社会经济地位在多大程度上解释了这种关联。
对来自洛锡安出生队列 1936 研究的 882 名参与者进行了分析。使用食物频率问卷的主成分分析提取了四种饮食模式，分别为“地中海式”、“健康意识”、“传统”和“甜食”。认知功能在 70 岁时进行评估，包括一般（g）认知能力、加工速度、记忆和语言能力。
在未调整儿童智商和社会经济地位的情况下，“地中海式”饮食模式与认知表现显著提高有关（效应大小为偏 eta 平方（ηp(2)）范围为 0.005 至 0.055），而“传统”饮食模式与老年时所有认知领域的表现较差有关（ηp(2)为 0.009 至 0.103）。在调整了儿童时期的智商（在 11 岁时测量）和社会经济地位后，大多数关联的统计学意义都丧失了，只有语言能力和“地中海式”模式除外（国家成人阅读测试（NART）ηp(2) = 0.006 和韦氏成人阅读测试（WTAR）ηp(2) = 0.013），以及“传统”模式（NART ηp(2) = 0.035 和 WTAR ηp(2) = 0.027）。
我们的研究结果表明存在反向因果关系或混淆；较高的儿童认知能力（和成人社会经济地位）预测了对“健康”饮食的依从性以及老年时更好的认知表现。我们的模型表明，老年时的饮食与认知表现之间没有直接联系；相反，它们通过智力这一终身稳定的特征相关联。
