Study On The Content Of Trace Element In Whole Blood And Their Relationship With Growth And Development Of Preschool Children In Chengguan District Of Lanzhou City

Objective:To analyze the contents of serum Cu,Zn,Ca,Mg,Fe and the levels of vitamin D₃in the whole blood of preschool children of different ages and genders in Chengguan district of Lanzhou.To understand the nutritional status,growth and development of children,and to explore the correlation between calcium and vitamin D₃,trace elements and children’s growth and development.It provides reference for guiding children’s scientific and reasonable diet in this area.Methods:From May to July 2019,1393 preschool children from 3 to 7 years old in the Pediatric Care Department of a district-level maternal and child health hospital in Lanzhou City were selected as the research objects.Basic data such as height and weight were obtained by physical examination.The contents of serum Cu,Zn,Ca,Mg,Fe in the whole blood and the level of vitamin D₃were determined by laboratory biochemical examination.The acquired data was double-entered with Epidata3.1 to establish a database.The levels and abnormal rates of serum Cu,Zn,Ca,Mg,Fe trace elements and vitamin D₃in preschool children of different ages and genders were compared by t-test,ANOVA and chi-square test.The Z-score and grade evaluation methods are used to evaluate the nutritional status,growth level and symmetry of children of different ages and genders.The correlation between the growth and development of children and trace elements was analyzed by Pearson.Results:1.Basic situationAmong the 1393 preschoolers,722（51.83%）were boys and 671（48.17%）were girls.There were 116 cases（8.33%）in 3 to 4 years old group,503 cases（36.11%）in 4to 5 years old group,491 cases（35.25%）in 5 to 6 years old group,and 283 cases（20.31%）in 6 to 7 years old group.The results showed that there were 876 cases（62.89%）of low serum Ca,191 cases（13.71%）of low serum Zn,132 cases（9.48%）of low serum Fe,36 cases（2.58%）of low serum Cu,and 4 cases（0.29%）of low serum Mg,996 cases（71.5%）of vitamin D₃deficiency,364 cases（26.13%）lack of vitamin D₃.2.Comparison of the levels of five trace elements and vitamin D₃in children of different ages and gendersAccording to the results,the deficiency rate of serum Ca was 62.89%,among which 6 to 7 years old children had the highest deficiency rate.There was significant difference in the mean between groups(χ~2₁₃=3.883,χ~2₁₄=12.932,χ~2₂₄=8.807,χ~2₃₄=6.249,P<0.05).The deficiency rate of serum Zn was 13.71%,among which the 3 to 4 years old children group had the highest deficiency rate.The deficiency rate of serum Fe was 9.48%,among which the deficiency rate was the highest in children aged 5 to 6years.The deficiency rate of serum Cu was 2.58%.Among them,the 6 to 7-year-old children group had the highest deficiency rate,and the difference in the mean between the groups was statistically significant（P<0.05）.Among the five elements,the deficiency rate of serum Mg was the lowest,which was 0.29%,and the content of serum Mg was relatively stable in all ages.There were statistically significant differences between the mean values of serum Cu and Fe in the whole blood of children of different ages(F_Cu=17.996,F_Fe=8.726,P<0.05).The concentrations of serum Zn and Fe increased with age,while the concentrations of serum Ca were on the contrary.The deficiency rate of vitamin D₃was 26.13%,of which 6 to 7 years old children group the deficiency rate of vitamin D₃is the highest.The mean values of vitamin D₃in boys and girls were 22.05±3.42ng/ml and 22.32±3.48ng/ml,respectively.There was statistically significant difference in the average content of vitamin D₃among children of different ages（F=4.638,P<0.05）.3.Evaluation results of children’s height and weight gradesThe results showed that all the grade evaluation of physical growth were mainly at the middle level,and the"middle"level accounted for a large proportion of children.64.28%of people with height and 73.75%of people with weight were in the"medium"level,followed by the"upper"level,and the"lower"level accounted for the lowest proportion（height grade at 0.72%,weight grade at 0.29%）.The results showed that there were statistically significant differences in the results of height grade evaluation among children of different genders and ages(H_gender=2.778,H_age=14.616,P<0.05).The result of weight grade evaluation was only statistically significant between boys and girls.Overweight and obesity occur in boys and girls in all age groups,and the overall performance is that the proportion of overweight is higher than obesity.The incidence of overweight among boys and girls was 9.36%and 6.45%respectively.Among them,boys were the highest incidence in the 4 to 5years old age group,reaching 10.15%,and the incidence in girls was the highest in the5 to 6 years old age group,reaching 8.73%.The incidence of obesity in boys and girls was 4.47%and 3.6%respectively.Among them,the incidence rate of boys was the highest in the age group of 6 to 7 years,reaching 9.62%,and the incidence of obesity in girls was the highest in the age group of 3 to 4 years,at 5.17%.The rates of underweight and emasurement in children were 0.3%,1.93%,and growth retardation rate was 0.72%,respectively.The growth retardation rate was the highest in boys and girls aged 6-7 years,and there was no low weight and growth retardation in boys aged3-4 years.The overall physical growth deviation rate of young children was 13.81%,and the difference in physical growth deviation rate of each age group was statistically significant（F=27.726,P<0.05）.4.Z score of children growth and development and nutritional status evaluation resultsThe WHZ value of children aged 3-4 years was negative,-0.08±0.85 for boys,-0.22±0.87 for girls,and the rest of the groups are all positive.The boy’s WAZ value gradually decreases with age before the age of 5.The WHZ value of boys increased while that of girls decreased.The comparison of the WHZ values of boys and girls among all age groups showed significant differences(F_male=7.524,F_female=3.149,P<0.05).There were statistically significant differences in HAZ and WAZ between boys(F_HAZ=0.003,F_WAZ=0.034,P<0.05).The HAZ values of both boys and girls are positive and coincide at the point of 5 years of age.Before the age of 5,the HAZ values show a decreasing trend with the increase of age,and the decreasing rate is the largest at the age of 3-4,and then increases steadily after the age of 5.The HAZ,WAZ,and WHZ values of boys and girls are close to the 5-year-old point,which are close to the national reference standard.5.Comparison of serum trace elements in children with different growth and development levelsThe results of correlation analysis showed that there was a positive correlation between height status and serum Fe,Cu,and Mg concentrations（P<0.05）,and the correlation coefficients were 0.069,0.024,and 0.018,respectively.There was a significant correlation between body weight and serum Cu and Fe concentrations（P<0.05）,and the correlation coefficients were 0.112 and 0.101,respectively.The serum Ca of the high-level group（-0.11±0.68mmol/L）is lower than the serum Ca of the middle-level height（0.00±1.1mmol/L）,and it is much lower than the serum Ca of the children in the low-level group（0.28±0.88mmol/L）,and there was significant difference between the low-level group and the high-level group（P<0.05）.The serum Cu of middle-weight group（-0.08±0.99μmol/L）is lower than that of the low-weight group（0.19±1.12μmol/L）and significantly lower than that of the high-weight group（0.24±0.95μmol/L）,and the difference between middle-weight group and high-weight group was statistically significant（P<0.05）.The serum Zn（-0.04±0.96μmol/L）in the middle-weight group was lower than that in the low-weight group（0.35±0.93μmol/L）,and the difference between the two groups was statistically significant（P<0.05）.The serum Fe（-0.06±0.98mmol/L）in the middle-weight group was lower than that in the low-weight group（0.11±1.08mmol/L）,and it was significantly lower than that in the high-weight group（0.21±1.04mmol/L）,and the difference between the middle-weight group and the high-weight group was statistically significant（P<0.05）.6.The association between trace elements in the bloodCorrelation analysis of trace elements in whole blood showed that serum Cu was positively correlated with serum Zn,Ca,Mg,Fe（P<0.05）,and r values were 0.245,0.094,0.308 and 0.212,respectively.Serum Cu was negatively correlated with vitamin D₃（r=-0.158）.Serum Mg and Fe were significantly positively correlated with serum Zn,and serum Ca and Fe were significantly positively correlated with serum Mg,respectively（P<0.05）.The correlation between serum Mg and Fe was 0.652,the correlation between serum Zn and Fe was 0.543,and the correlation between serum Mg and Zn was 0.433.Conclusions:1.The five trace elements were deficient in preschool children of different ages in Chengguan District of Lanzhou.The deficiency rate of serum Ca is higher than that of other elements.Among them,children aged 6 to 7 have the highest deficiency rate.2.With increasing age,the deficiency rate of serum Ca and Cu in all children increases,that is,children in the 6 to 7-year-old group have the most serious Ca deficiency,followed by Cu.There was a low degree of positive correlation between serum Ca and vitamin D₃content in children.3.The physical development of preschool children in Chengguan District of Lanzhou is mainly at the middle level.The height and weight of children increase slowly when they are 3-5 years old,but change obviously when they are 5-7 years old.The weight of boys aged 4 to 5 years is lower than that of girls of the same age,and the height and weight of boys in other age groups are higher than that of girls of the same age.4.The overall physical development level of preschool children in this area is slightly higher than the reference standard of growth and development of children under 7 years old in China.The age of 5 is the key point for the growth and development of preschool children in this area,and there are abnormal growth and development around 5 years old.5.The lack of serum Ca,Cu,Mg and Fe in the whole blood will affect the height development of preschoolers,while the concentration of trace elements Cu,Zn and Fe will affect the weight development of preschoolers.6.The relationship between trace elements in the whole blood of the research subjects is complex and lacks regularity,which needs to be further studied.