学龄前儿童血红蛋白浓度与智力发育水平的相关性研究

Correlation on hemoglobin concentration and the development of cognition among pre-school children

目的探讨学龄前儿童血红蛋白（Hb）浓度与智力发育水平之间的相关性。方法研究对象为河北、江苏、浙江3省21个市县1993—1996年出生的7331名儿童。平均54月龄时测量Hb浓度；平均68月龄时使用中国-韦氏幼儿智力量表进行智力测试。分析Hb浓度与全量表智商、语言智商和操作智商得分之间的关系。结果贫血组与非贫血组儿童的语言智商得分分别为91．6±18．0、92．3±17．5（P=0．144），操作智商得分分别为102．2±15．6、103．1±15．0（P=0．055），全量表智商得分分别为96．4±17．1、97．3±16．4（P=0．079）。调整儿童性别、智力测量时月龄、地区、产次以及母亲智商、文化程度、职业等因素之后，贫血组儿童发生低语言智商、操作智商、全量表智商得分的风险是非贫血儿童的1．3倍（OR=1．3，95％CI：1．1～1．6）、1-3倍（OR=1.3，95％CI：1．1～1．5）和1．4倍（OR=1．4，95％CI：1．2～1．6）。按照每20个百分位间隔将Hb浓度分成5组分析，Hb浓度偏低组（Hb〈110g／L）、中等浓度组（117g／L~〈Hb〈122gm）、偏高组（Hb≥130g／L）JL童的语言智商得分分别为90．6±18．1、94．0±17．6、91．0±16．4；操作智商得分分别为102．2±15．7、104．6±14．8、100．5±14．9，全量表智商得分分别为95．9±17．3、99．0±16．4、95．2±15．6；Hb浓度偏低或偏高组儿童的智力得分均低于Hb水平中等组，差异有统计学意义（P〈0．001）。调整混杂因素后，Hb浓度偏低组儿童发生语言智商、操作智商、全量表智商得分较低的风险是Hb浓度中等浓度组儿童的1．4倍（OR=1．4，95％CI：1．1～1．7）、1．4倍（OR=1．4，95％CI：1．1～1．8）和1．5倍（OR=1．5，95％CI：1．2～1．8）。未见Hb浓度偏高组儿童发生低智商得分的风险高于Hb水平中等组。结论儿童低Hb浓度可能对智力发育有不利影响。

Objective Our purpose was to evaluate the association between hemoglobin concentration （Hb） and cognitive ability of children at 4-6 years of age in 21 counties/cities in China. Methods A total number of 7331 children born during 1993-1996 were randomly selected from 21 counties or cities in Hebei, Jiangsu and Zhejiang provinces. Hb concentration of children were measured followed by three tests including full-scale, verbal and performance intelligence quotient （IQ） test performed by Chinese-Wechsler Intelligence Scale for Children, one year later. Results There were a 0.7 point difference in mean verbal scale IQ （P=0.144） and a 0.9 point difference in both mean performance and full-scale IQ （P=0.055 and 0.079, respectively） between anemia and non-anemia groups. Compared with children with non-anemia, children with anemia were 1.3-fold more likely to score poorly in verbal IQ and operational IQ （95% CI： 1.1-1.6, 1.1-1.5, respectively） and 1.4-fold more likely to have had poor scores in full-scale IQ（95%CI： 1.2-1.6） after controlled for children＇s gender, age at intelligence test, region, parity and mother＇s IQ, education level, occupation. Participants were divided into 5 sub-groups according to Hb concentration of every 20 percentile. Verbal IQ scores of the lowest （Hb〈 110 g/L）, moderate （117 g/L≤ Hb〈 122 g/L） and the highest Hb concentration groups （Hb≥ 130 g/L） were 90.6 ± 18.1,94.0 ± 17.6 and 91.0± 16.4, respectively. Performance IQ scores were 102.2 ± 15.7,104.6±14.8 and 100.5±14.9, respectively. Full-scale IQ scores were 95.9 ± 17.3,99.0 ± 16.4 and 95.2 ± 15.6, respectively. Children with both low and high hemoglobin levels did poorly in all intelligence tests than children with moderate Hb concentration （P〈0.001）. After controlling for confounding factors, children with the lowest concentration were 1.4-fold more likely to have had poor verbal and performance scores than children with moderate Hb concentration （95% C,I： 1.1-1.7, 1.1-1.8, respectively） and 1.5-fold （95% CI： 1.2-1.8） more likely to have had poor full-scale scores than those with moderate Hb concentration. The association between high Hb concentration and low IQ scores disappeared in the multivariate model. Conclusion Low Hb concentration might have adversely affected children＇ s cognitive development.