MRC Centre for Causal Analysis in Translational Epidemiology, School of Social and Community Medicine, University of Bristol, Oakfield House, 15-23 Oakfield Grove, Clifton, Bristol BS8 2BN, UK.
J Epidemiol Community Health. 2012 Dec;66(12):1137-42. doi: 10.1136/jech-2011-200114. Epub 2012 Apr 9.
Higher total serum 25-hydroxyvitamin D (25(OH)D) concentrations have been associated with better cognitive function mainly in cross-sectional studies in adults. It is unknown if the associations of different forms of 25(OH)D (25(OH)D(3) and 25(OH)D(2)) are similar.
Prospective cohort study (n=3171) with serum 25(OH)D(3) and 25(OH)D(2) concentrations measured at mean age of 9.8 years and academic performance at age 13-14 years (total scores in English, mathematics and science) and 15-16 years (performance in General Certificates of Education examinations).
Serum 25(OH)D(3) concentrations were not associated with any educational outcomes. Higher 25(OH)D(2) concentrations were associated with worse performance in English at age 13-14 years (adjusted SD change per doubling in 25(OH)D(2) (95% CI) -0.05 (-0.08 to -0.01)) and with worse academic performance at age 15-16 years (adjusted OR for obtaining ≥5 A*-C grades (95% CI) 0.91 (0.82 to 1.00)).
The null findings with 25(OH)D(3) are in line with two previous cross-sectional studies in children. It is possible that the positive association of 25(OH)D with cognitive function seen in adults does not emerge until later in life or that the results from previous cross-sectional adult studies are due to reverse causality. The unexpected inverse association of 25(OH)D(2) with academic performance requires replication in further studies. Taken together, our findings do not support suggestions that children should have controlled exposure to sunlight, or vitamin D supplements, in order to increase academic performance.
在成人的横断面研究中，较高的血清总 25-羟维生素 D（25(OH)D）浓度与更好的认知功能相关。但不同形式的 25(OH)D（25(OH)D(3) 和 25(OH)D(2)）之间的关联是否相似，目前尚不清楚。
前瞻性队列研究（n=3171），在平均年龄为 9.8 岁时测量血清 25(OH)D(3) 和 25(OH)D(2)浓度，并在 13-14 岁（英语、数学和科学的总分）和 15-16 岁（普通教育证书考试的成绩）评估学业表现。
血清 25(OH)D(3)浓度与任何教育结果均无关。较高的 25(OH)D(2)浓度与 13-14 岁时英语成绩较差有关（25(OH)D(2)每增加一倍的调整 SD 变化（95%CI）-0.05（-0.08 至-0.01）），且与 15-16 岁时学业成绩较差有关（获得≥5 个 A*-C 级成绩的调整 OR（95%CI）0.91（0.82 至 1.00））。
25(OH)D(3)的阴性结果与两项先前的儿童横断面研究一致。成人中维生素 D 与认知功能的正相关关系可能要到以后的生活中才会出现，或者之前成人的横断面研究结果是由于反向因果关系造成的。25(OH)D(2)与学业成绩之间意外的负相关关系需要在进一步的研究中进行复制。总的来说，我们的研究结果不支持儿童应控制暴露在阳光下或补充维生素 D，以提高学习成绩的建议。
