The aim of this study was to evaluate the blood levels of folic acid, vitamin B12, and 25-hydroxyvitamin D (25-OHD) in patients with lead poisoning compared with control subjects in Eastern Iran. This analytical case-control study was conducted on 40 lead-poisoned patients who were referred to Imam Reza Hospital in Birjand from 2018 to 2019. Blood samples were collected from an additional 40 individuals without lead poisoning as a control group. The results indicated that the mean vitamin B12, vitamin D, and folic acid levels for the case group were 356.5 ± 200.1 pg/ml, 24.38 ± 9.5 ng/ml, and 7.4 ± 3.7 ng/ml, respectively. Mean folic acid level in the case group was significantly lower than control group (7.4 ng/ml vs. 12.70 pg/ml, P = 0.001), whereas the mean of the vitamin D levels at the case group was significantly higher than that of the control group (24.3 ng/ml vs. 20.1 ng/ml, P = 0.03). Moreover, mean vitamin B12 levels were significantly lower in the case group in comparison with the control group (356.5 pg/ml vs. 500.8 pg/ml) (P < 0.001). In the control group, 3 patients had folic acid below normal level (< 6 ng/mL) while 12 cases had folic acid below normal (P < 0.05). Also, none of the control group had low vitamin B12 concentrations (< 180 pg/ml), while 7 cases had vitamin b12 below normal (P < 0.05). Our results suggest that lead may induce folate and vitamin B12 dysregulation. Although we found that vitamin D levels were insufficient in both case and control groups, they were significantly higher in the case group. The interpretation of this result is unclear given inconsistent literature reports on this relationship.

中文翻译：

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伊朗东部铅垂症患者和对照组的维生素 B12、维生素 D 和叶酸血液水平的比较。

本研究的目的是评估与伊朗东部的对照受试者相比，铅中毒患者的叶酸、维生素 B12 和 25-羟基维生素 D (25-OHD) 的血液水平。这项分析性病例对照研究是对 2018 年至 2019 年转诊到比尔詹德伊玛目礼萨医院的 40 名铅中毒患者进行的。另外 40 名没有铅中毒的人作为对照组收集了血液样本。结果表明，病例组的平均维生素 B12、维生素 D 和叶酸水平分别为 356.5 ± 200.1 pg/ml、24.38 ± 9.5 ng/ml 和 7.4 ± 3.7 ng/ml。病例组的平均叶酸水平显着低于对照组（7.4 ng/ml vs. 12.70 pg/ml，P = 0.001），而病例组维生素 D 水平的平均值显着高于对照组（24.3 ng/ml vs. 20.1 ng/ml，P = 0.03）。此外，与对照组相比，病例组的平均维生素 B12 水平显着降低（356.5 pg/ml 对 500.8 pg/ml）（P < 0.001）。对照组中，3例患者叶酸低于正常水平（<6ng/mL），12例患者叶酸低于正常水平（P<0.05）。此外，对照组没有一个维生素 B12 浓度低（< 180 pg/ml），而 7 个病例的维生素 B12 低于正常值（P < 0.05）。我们的结果表明，铅可能会导致叶酸和维生素 B12 失调。虽然我们发现病例组和对照组的维生素 D 水平都不足，但病例组的水平明显更高。