Thurnham David I
Northern Ireland Centre for Food and Health, School of Biomedical Sciences, Coleraine, United Kingdom
Food Nutr Bull. 2015 Sep;36(3):290-8. doi: 10.1177/0379572115597514. Epub 2015 Aug 27.
Serum retinol concentrations are homeostatically controlled and only fall when liver stores of vitamin A are very low. Nevertheless, low concentrations of serum retinol occur in apparently healthy people where there is no evidence of vitamin A deficiency (VAD).
To determine the reason for low serum vitamin A concentrations where there is no VAD.
We observed that elevated acute-phase protein (APP) concentrations often accompanied low retinol concentrations, and we developed a model of the inflammatory response to categorize 4 groups of participants termed reference (no raised APP), incubation (raised acute APP only), early convalescence (both acute and chronic APP raised), and late convalescence (raised chronic APP only). We identified 7 studies with participants who could be allocated to the 4 groups, and using meta-analysis methods we calculated correction (ie, multiplication) factors 1.13, 1.24, and 1.11 to remove the influence of inflammation from the incubation, early, and late convalescent groups, respectively.
In nutrition surveys or intervention studies to measure vitamin A status, workers should measure APP and correct retinol concentrations using the multiplication factors where inflammation is found.
血清视黄醇浓度受稳态控制，只有当肝脏维生素A储备非常低时才会下降。然而，在没有维生素A缺乏（VAD）证据的明显健康人群中也会出现低血清视黄醇浓度。
确定无VAD时血清维生素A浓度低的原因。
我们观察到急性期蛋白（APP）浓度升高常伴有视黄醇浓度降低，我们建立了一个炎症反应模型，将4组参与者分类为参考组（APP未升高）、潜伏期（仅急性APP升高）、早期恢复期（急性和慢性APP均升高）和晚期恢复期（仅慢性APP升高）。我们确定了7项研究，其参与者可被分配到这4组中，并使用荟萃分析方法分别计算出校正（即相乘）因子1.13、1.24和1.11，以消除潜伏期、早期和晚期恢复期组炎症的影响。
在营养调查或测量维生素A状态的干预研究中，工作人员应测量APP，并在发现炎症时使用相乘因子校正视黄醇浓度。
