McKing Consulting Corporation, Atlanta, GA USA.
Hubert Department of Global Health, Rollins School of Public Health, Emory University, Atlanta, GA, USA.
Am J Clin Nutr. 2021 Apr 6;113(4):854-864. doi: 10.1093/ajcn/nqab004.
Reduction of vitamin A deficiency (VAD) in Malawi coincided with introduction of vitamin A-fortified staple foods, alongside continued biannual high-dose vitamin A supplementation (VAS).
We describe coverage of vitamin A interventions and vitamin A status in the 2015-2016 Malawi Micronutrient Survey.
Food samples and biospecimens were collected within a representative household survey across 105 clusters. Retinol was measured using ultraviolet excitation fluorescence (sugar) and photometric determination (oil). Preschool children (PSC, aged 6-59 mo, n = 1102), school-age children (SAC, aged 5-14 y, n = 758), nonpregnant women (n = 752), and men (n = 219) were initially assessed for vitamin A status using retinol binding protein (RBP) and modified relative dose response (MRDR). Randomly selected fasted MRDR participants (n = 247) and nonfasted women and children (n = 293) were later assessed for serum retinol, retinyl esters, and carotenoids. Analyses accounted for complex survey design.
We tested sugar and oil samples from 71.8% and 70.5% of the households (n = 2,112), respectively. All of the oil samples and all but one of the sugar samples had detectable vitamin A. National mean retinol sugar and oil contents were 6.1 ± 0.7 mg/kg and 6.6 ± 1.4 mg/kg, respectively. Receipt of VAS in the previous 6 mo was reported by 68.0% of PSC. VAD prevalence (RBP equivalent to <0.7µmol retinol/L) was 3.6% in PSC, and <1% in other groups. One woman and no children had MRDR ≥0.060 indicating VAD. Among fasted PSC and SAC, 18.0% (95% CI: 6.4, 29.6) and 18.8% (7.2, 30.5) had >5% of total serum vitamin A as retinyl esters, and 1.7% (0.0, 4.1) and 4.9% (0.0, 10.2) had >10% of total serum vitamin A as retinyl esters. Serum carotenoids indicated recent intake of vitamin A-rich fruits and vegetables.
Near elimination of VAD in Malawi is a public health success story, but elevated levels of vitamin A among children suggests that vitamin A interventions may need modification.
马拉维的维生素 A 缺乏症（VAD）减少与维生素 A 强化主食的引入以及持续的每半年一次的高剂量维生素 A 补充（VAS）同时发生。
我们描述了 2015-2016 年马拉维微量营养素调查中维生素 A 干预措施和维生素 A 状况的覆盖范围。
在 105 个集群的代表性家庭调查中收集了食物样本和生物样本。使用紫外线激发荧光（糖）和分光光度法（油）测量视黄醇。对 6-59 个月大的学龄前儿童（PSC，n=1102）、5-14 岁的学童（SAC，n=758）、非孕妇（n=752）和男性（n=219）使用视黄醇结合蛋白（RBP）和改良相对剂量反应（MRDR）进行了初始维生素 A 状况评估。随机选择禁食 MRDR 参与者（n=247）和非禁食妇女和儿童（n=293）进行血清视黄醇、视黄酯和类胡萝卜素检测。分析考虑了复杂的调查设计。
我们分别测试了 71.8%和 70.5%的家庭（n=2112）的糖和油样本。所有油样和除一份糖样之外的所有油样都检测到了维生素 A。全国平均视黄醇糖和油含量分别为 6.1±0.7mg/kg 和 6.6±1.4mg/kg。68.0%的 PSC 报告在过去 6 个月内接受了 VAS。PSC 的 VAD 患病率（RBP 相当于<0.7µmol 视黄醇/L）为 3.6%，其他组则<1%。一名妇女和没有儿童的 MRDR≥0.060 表明患有 VAD。在禁食的 PSC 和 SAC 中，18.0%（95%CI：6.4，29.6）和 18.8%（7.2，30.5）的总血清维生素 A 中有>5%为视黄酯，1.7%（0.0，4.1）和 4.9%（0.0，10.2）的总血清维生素 A 中有>10%为视黄酯。血清类胡萝卜素表明近期摄入了富含维生素 A 的水果和蔬菜。
马拉维 VAD 的近乎消除是公共卫生的成功案例，但儿童体内维生素 A 水平升高表明维生素 A 干预措施可能需要调整。
