Zinc (Zn) is an essential micronutrient, and Zn deficiency remains a major global public health challenge. Recognised biomarkers of population Zn status include blood plasma or serum Zn concentration and proxy data such as dietary Zn intake and prevalence of stunting. Urine Zn concentration is rarely used to assess population Zn status. This study assessed the value of urine Zn concentration as a biomarker of population Zn status using a nationally representative sample of non-pregnant women of reproductive age (WRA) and school-aged children (SAC) in Malawi. Spot (casual) urine samples were collected from 741 WRA and 665 SAC. Urine Zn concentration was measured by inductively coupled plasma mass spectrometry with specific gravity adjustment for hydration status. Data were analysed using a linear mixed model with a spatially correlated random effect for between-cluster variation. The effect of time of sample collection (morning or afternoon), and gender (for SAC), on urine Zn concentration were examined. There was spatial dependence in urine Zn concentration between clusters among SAC but not WRA, which indicates that food system or environmental factors can influence urine Zn concentration. Mapping urine Zn concentration could potentially identify areas where the prevalence of Zn deficiency is greater and thus where further sampling or interventions might be targeted. There was no evidence for differences in urine Zn concentration between gender (P = 0.69) or time of sample collection (P = 0.85) in SAC. Urine Zn concentration was greater in afternoon samples for WRA (P = 0.003). Relationships between urine Zn concentration, serum Zn concentration, dietary Zn intake, and potential food systems covariates warrant further study.

中文翻译：

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马拉维育龄妇女和学龄儿童尿锌 (Zn) 浓度的空间分析。

锌 (Zn) 是一种必需的微量营养素，缺锌仍然是全球公共卫生的主要挑战。公认的人群锌状态生物标志物包括血浆或血清锌浓度和代用数据，例如膳食锌摄入量和发育迟缓的患病率。尿锌浓度很少用于评估人群锌状态。本研究使用具有全国代表性的马拉维育龄妇女 (WRA) 和学龄儿童 (SAC) 样本，评估了尿锌浓度作为人口锌状况生物标志物的价值。从 741 WRA 和 665 SAC 收集现场（临时）尿液样本。通过感应耦合等离子体质谱法测量尿锌浓度，并根据水合状态调整比重。使用线性混合模型对数据进行分析，该模型具有空间相关的随机效应，用于集群间的变化。检测了样本采集时间（早上或下午）和性别（对于 SAC）对尿锌浓度的影响。SAC组间尿Zn浓度存在空间依赖性，而WRA则没有，这表明食物系统或环境因素会影响尿Zn浓度。绘制尿锌浓度图可以潜在地确定缺锌流行率较高的区域，因此可能有针对性地进行进一步的采样或干预。没有证据表明 SAC 中不同性别 (P = 0.69) 或样本采集时间 (P = 0.85) 之间的尿锌浓度存在差异。WRA 的下午样本中尿锌浓度更高（P = 0.003）。