中文摘要：

目的了解重庆市永川区乡镇3～6岁留守儿童维生素D营养状况，探讨维生素D受体基因FOKI位点多态性与25一羟维生素D[25．（OH）D]的相关性。方法2015年11月-2016年4月期间，由重庆医科大学附属永川医院招募永川区部分乡镇3～6岁留守儿童进行健康体检，以非留守儿童作为对照，采用液相色谱串联质谱法进行血清25．（OH）D水平检测，采用聚合酶链反应限制性片段长度多态性（PCR-RFLP）法进行FOKI位点基因型检测。结果①285例3～6岁留守儿童血清25-（OH）D平均水平为（19．566±5．185）ng／mL，维生素D充足占2．81％；不足组占41．40％；缺乏占52．98％；严重缺乏占2．81％。留守儿童组血清25-（OH）D较之非留守儿童组低，但两组比较无显著差异。其中3岁组25-（OH）D平均水平最高，各年龄组维生素D水平比较差异有统计学意义（P〈0．001）。②ff基因型的维生素D水平较其余2种基因型低，但3种基因型的维生素D水平差异无显著统计学意义（P〉0．05）。采用协方差分析校正年龄对维生素D水平的影响后，各基因型维生素D水平相比较差异仍无显著统计学意义（P〉0．05）。结论重庆市永川区留守儿童25-（OH）D水平严重低下，需采取措施提高维生素D水平，VDR受体基因FOKI位点多态性可能与25．（OH）D水平无关。

英文摘要：

Objective To investigate the status and deficiency of 25-hydroxy vitamin D [ 25-（OH） D] in left-behind children at 3 -6 years old living in Yongchuan District, Chongqing, and to explore the correlation of vitamin D receptor （VDR） genetic polymorphism FOK I and serum levels of 25-（OH） D3. Methods A total of 285 left-behind children at the age of 3 to 6 living in some towns of Yongchuan District were recruited in our hospital during November 2015 to April 2016. They all took physical examination, and their serum level of 25-（OH） D was detected by liquid chromatography-tandem mass spectrometry. The genotypes of FOK I polymorphisms for VDR gene were analyzed with polymerase chain reaction-restriction fragment length polymorphism （PCR-RFLP）. Results ① The average serum level of 25-（ OH ）D was 19.566-＋5. 185 ng/mL in the 285 children, with 8 cases （2. 81%） sufficient, 118 cases （41.40%） insufficient, 151 cases （52.98%） deficient and 8 cases （2.81%） severely deficient. The level was lower in the left-behind children than the non-left-behind children, though no statistical difference. The level was the highest in the 3-yea-old group, and statistical differences were observed among the different age groups （P 〈 O. 001 ）. ② The serum level of 25-（OH） D was lower in the children with ff genotype than those with Ff and FF genotypes, but there was no statistical difference among different genotypes groups （P 〉 0. 05 ）. Covariance analysis indicated that there was no statistical difference in the serum level of 25-（OH） D among the different genotypes groups after adjustment of age （ P 〉 0.05 ）. Conclusion The serum level of 25- （OH） D is severely low in the left-behind children at the age of 3 to 6 in Yongchuan District. Some measures should be implied to improve the levels. Fok I polymorphisms in VDR gene might have no correlation with the serum level of 25-（OH） D.