Z-score Analysis Of Physical Growth Of Children Under5Years Of Age In Tongliang County Of Chongqing

Objective: Evaluation of the children’s physical growth in the airpollution environment，and provide some Epidemiological basis to thefurther exploration about the effects of air pollution on children’s physicalgrowth.Methods:A random sample of150neonates delivered by pregnantwomen who meet the criteria, between March2002and May2002. Thisstudy measured the weight, height and head circumference respectively inat birth,and at the age of18months,24months,30months,42months,54months and60months. Calculated z-scores of weight for age（WAZ),heightfor age(HAZ), weight for height(WHZ), BMI for age (BAZ),and headcircumference for age(HCZ) through WHO Anthro2011v.2.2software andChinese children physique growth and nutrition evaluation system softwarebased on standards of both WHO Child Growth Standards(2006) andgrowth standard for Chinese children(2005),which were obtained toevaluation growth level、 growth velocity and the rates of underweight, stunting, wasting, overweight，microcephaly and macrocephaly in eachmonth.Results: The results of z-scores were calculated based on WHO ChildGrowth Standards(2006):the height or length of the children at the age of24m and54month for female and at the age of24m,30m,42m and54month for male were lower than that of the average level of WHO ChildGrowth Standards(2006)（P<0.05);the weight of the children at the age of18m,24m and30month for male and at the age of18m24m and30monthfor female were lower than that of the average level of WHO Child GrowthStandards(2006)（P<0.05); the head circumference of the children apartfrom the age of30month for male were lower than that of the average levelof WHO Child Growth Standards(2006)(P<0.05)，the head circumferenceof the children at every month of age for female were reach the averagelevel of WHO Child Growth Standards(2006)(P>0.05).The incidence ofunderweight， overweight and stunting at every month of age of childrenwere lower than that of average rates in the world in the period from2000to2009.The rates of microcephyaly and macrocephaly under5years of agewere8.7%and6.0%(whenever the situation above was happen to thechild,it was calculated one time). The average of△WAZ from at birth to18months and△LAZ from at birth to18months for male and from18mto24months for female were lower than-0.67,which indicated the weight growth was insufficient, and the average of△HCZ from24monthto30month was beyond+0.67for boys，which indicated the weight growthwas accelerated. However, growth rate of weight,height and headcircumference during other period were in the normal range.The results of z-scores were calculated based on growth standard forChinese children(2005): the height or length of the children apart from theage of at birth were lower than that of the average level of the growthstandard for Chinese children(2005)（P<0.05);the weight of the childrenapart from the age of at birth,42m and54month for male and apart fromthe age of at birth for female were lower than that of the average level ofthe growth standard for Chinese children(2005)（P<0.05); the headcircumference of the children at every age for both male and at the age of0m、18m and24month for female were lower than that of the average levelof the growth standard for Chinese children(2005)（P<0.05). The incidenceof underweight(apart from the age of at birth and42month formale),stunting(apart from the age of at birth for female) and wasting(apartfrom the age of at birth and18month for male and at the age of30monthfor female)were beyond that of average rates in china.The rates ofmicrocephyaly and macrocephaly under5years of age were17.3%and5.3%(whenever the microcephyaly and macrocephaly happen to thechild,it was calculated one time). The average of△WAZ and△HAZ from at birth to18months was lower than-0.67,which indicated the weightgrowth is insufficient, and the average of△HCZ from24month to30month was beyond+0.67for boys and girls，which indicated the weightgrowth was accelerated. However, growth rate of weight,height and headcircumference during other period were in the normal range.Conclution: In this study,the average level of physical growth ofchildren in height(length),weight and head circumference were low（especially the head circumference for male），but most of them were inthe normal range;the growth velocity of height（length）and weight wereinsufficient from0month to18month,but the others were in the normalgrowth;although average level of head circumference were low,but it wereaccelerate from24m to30month, and the others were in the normal growth.the incidence of stunting, underweight and overweight at every month ofage were lower than that of in WHO,but most month of age of theincidence of stunting,wasting and underweight were higher than that of inchina.The air pollution may have effection on the children’s physicalgrowth to some degree, however, this kind of effection still needs furtherexploration，which can be basis for the instruction of early intervention.