重庆地区学龄前儿童血清维生素B12营养状况调查

目的了解学龄前儿童维生素B12（VB12）的营养水平,探讨血清VB12水平与营养性贫血的关系,并对相关因素进行分析。方法随机对重庆市四所幼儿园351名2—7岁儿童进行体格测量及血常规筛查,对其中177名进行膳食调查、血清VB12测定。结果学龄前儿童血清VB12平均水平为552pg／ml,VB12缺乏（血清VB12〈200pg／ml）检出率为4．5％（8／177）,边缘性缺乏（血清VBl2200—300pg／m1）检出率为10．7％（19／177）。学龄前儿童血清VB12无性别和年龄差异（P〉0．05）。血清VB12水平与血红蛋白水平无相关性。多因素逐步回归分析显示血清VB12水平主要受膳食VB12摄入量的影响（P=0．03）。8例VB12缺乏儿童体格发育正常,仅1例为小细胞性贫血,其余7例红细胞数目、红细胞平均体积及平均红细胞血红蛋白量均在正常范围内。结论学龄前儿童血清VB12水平明显高于成人,提示血清VB12水平存在年龄差异,2—7岁儿童血清VB12较稳定。血清VB12水平与血红蛋白水平无相关性,儿童VB12缺乏不一定是典型的大细胞性贫血。膳食中VB12含量是影响儿童血清VB12水平的重要因素。

Vitamin B12 nutritional status in preschool children in Chongqing

Objective To explore the levels of serum vitamin B_(12)(VB_(12)) in preschool children,determine the relationship between the levels of serum VB_(12) and anemia,and analyze the effects of several factors related to the level of serum VB_(12).Methods From March 2005 to July 2005,the weight,height and complete blood count(CBC) were studied in 351 children aged 2 to 7 years from 4 kindergartens of Chongqing.The concentrations of serum VB_(12) and the dietary survey of 177 of the children were evaluated.Results The average level of serum VB_(12) for the preschool children was 552 pg/ml.The levels of serum VB_(12) in 4.5%(8/177)of the children were below 200 pg/ml (defined as VB_(12) deficiency),in 10.7%(19/177)of the children were 200300 pg/ml(called marginal deficiency).There were no significant differences in the levels of serum VB_(12) between boys and girls.And there was no correlation between the levels of serum VB_(12) and hemoglobin.The results of multivriate stepwise regression analysis showed that the concentrations of serum VB_(12) were mainly influented by the contents of VB_(12) in the foods((P=0.03).)Eight of the children with normal growth and development were diagnosed as VB_(12) deficiency,only one of them was diagnosed microcytic hypochromatic anemia.The ranges of Hb,MCV and MHC were normal in the other 7 children.Conclusions The levels of serum VB_(12) of preschool children were higher than that of adults,suggesting that the levels of serum VB_(12) change with age.There were no significant differences in the levels of serum VB_(12) in 2-7 years old children between sex and ages.The levels of serum VB_(12) were not correlated with the concentrations of hemoglobin.Macrocytic anemia may not occur in preschool children with VB_(12) deficiency.The intake of VB_(12) from the diets was one of the important factors for preschool children to keep the normal ranges of serum VB_(12).It is beneficial for children to consume foods enriched with VB_(12) to keep the normal level of serum VB_(12).