Center for Human Nutrition, Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD.
National Food and Nutrition Commission, Lusaka, Zambia.
J Nutr. 2018 Jul 1;148(7):1160-1166. doi: 10.1093/jn/nxy069.
Impairments in visual function have been well characterized in vitamin A deficiency. However, eye function may also be sensitive to other nutrient deficiencies.
We examined associations between visual function-characterized by pupillary threshold or pupillary responsiveness-and nutritional status in Zambian children.
We used digital pupillometry to measure visual responses to calibrated light stimuli (-2.9 to 0.1 log cd/m2) among dark-adapted children aged 4-8 y (n = 542). We defined pupillary threshold as the first light stimulus at which pupil diameter decreased by ≥10% and considered a pupillary threshold ≥-0.9 log cd/m2 as impaired. Pupillary responsiveness was defined by absolute percentage of change in pupil diameter from pre- to poststimulus. We tested associations between these measures and serum concentrations of retinol, β-carotene, ferritin, soluble transferrin receptor, and hemoglobin (Hb <11.0 or 11.5 g/dL were used to define anemia, depending on age), as well as anthropometric indexes, with the use multilevel mixed-effects models.
Pupillary threshold was correlated only with serum retinol (r = 0.12, P < 0.05). The strongest correlates of pupillary responsiveness were Hb (r = -0.16, P < 0.01), height-for-age z score (r = 0.14, P < 0.05), weight-for-age z score (r = 0.14, P < 0.05), and soluble transferrin receptor (r = 0.12, P < 0.05). In multivariate models, anemia was positively associated with pupillary responsiveness (β = 2.99; 95% CI: 1.26, 4.72).
In this marginally nourished population, we found positive correlations between vitamin A status, iron status, or anthropometric indexes and visual function. Hb was negatively associated with visual function, with greater pupillary responsiveness among anemic children. We posit that this may signal altered parasympathetic activity, possibly driven by infection. Future studies should consider a broader range of indicators to better characterize the relation between nutrition and visual function. This trial was registered at clinicaltrials.gov as NCT01695148.
维生素 A 缺乏症已被充分描述了视力功能的损害。然而，眼睛功能也可能对其他营养缺乏敏感。
我们研究了赞比亚儿童的视觉功能（由瞳孔阈值或瞳孔反应来表征）与营养状况之间的关系。
我们使用数字瞳孔计来测量 4-8 岁暗适应儿童对校准光刺激（-2.9 至 0.1 log cd/m2）的视觉反应（n=542）。我们将瞳孔阈值定义为第一个光刺激，当瞳孔直径减少≥10%时，将瞳孔阈值定义为受损。瞳孔反应由刺激前后瞳孔直径的绝对百分比变化来定义。我们使用多级混合效应模型来测试这些措施与血清视黄醇、β-胡萝卜素、铁蛋白、可溶性转铁蛋白受体和血红蛋白（Hb<11.0 或 11.5 g/dL 用于定义贫血，取决于年龄）以及人体测量指标之间的关联。
瞳孔阈值仅与血清视黄醇相关（r=0.12，P<0.05）。瞳孔反应的最强相关因素是 Hb（r=-0.16，P<0.01）、身高年龄 z 评分（r=0.14，P<0.05）、体重年龄 z 评分（r=0.14，P<0.05）和可溶性转铁蛋白受体（r=0.12，P<0.05）。在多变量模型中，贫血与瞳孔反应呈正相关（β=2.99；95%CI：1.26，4.72）。
在这个边缘营养人群中，我们发现维生素 A 状态、铁状态或人体测量指标与视觉功能之间存在正相关。Hb 与视觉功能呈负相关，贫血儿童的瞳孔反应更大。我们推测这可能表明副交感神经活动发生改变，可能是由感染引起的。未来的研究应考虑更广泛的指标来更好地描述营养与视觉功能之间的关系。该试验在 clinicaltrials.gov 上注册为 NCT01695148。
