The Study On Catch-up Growth Correlation With Insulin Resistance In Children With Full Term Small For Gestational Age

Background:SGA (small for gestational age, SGA) infants are newborns with birth weight10%lower than other infants in the same gestational age or with weight2standard deviations lower than the average weight. Divided by gestational age preterm, term was expired producing small for gestational age child to full term gestational age infants mainly. The incidence of SGA infants in China is6.05-13.01%. Over the past decade, a large number of epidemiological investigation confirmed the SGA infants with adult metabolic syndrome (including impaired glucose tolerance, non-insulin-dependent diabetes mellitus, hypertension, coronary heart disease, etc.) related to one of the pathological mechanisms may be insulin resistance.Approximately50-80%of SGA infants born during the first two years in the fast-growing phenomenon of catch-up, catch the majority of SGA infants to normal infants of the same age-2SD～1SD. Cianfarani, etc. According to SGA infants the ability to adapt to rapid extra uterine environment proposed a "catch-up growth leads to insulin resistance," whose hypothesis is that the SGA in the prenatal period is in a state of chronic nutritional deficiency, decreased production of insulin, and insulin-like growth factor (IGF) system is shut down, which leads to intrauterine growth retardation, accompanied by low levels of insulin at birth, insulin-like growth factor1(IGF-1) and insulin-like growth factor binding protein3(IGFBP-3). The nutrient supply normalizes after birth, so that SGA individuals IGF system startup, insulin production increases, sudden exposure to high levels of the hormone environment, based on metabolic defense mechanism, the body of the infant produces peripheral insulin resistance against excessive insulin-like effect. This hypothesis also suggests that insulin resistance may occur when SGA catch associated with the height/weight after birth. The faster of the SGA infants born after individual growth pursued, adulthood in the higher the risk of metabolic disorders.Eriksson’s study first revealed the relationship between growth and catch up with insulin, the study reported that low birth weight associated with catch-up growth after birth to7years of age has reached or exceeded the normal BMI individuals with coronary heart disease mortality was significantly increased; Veening study confirmed that SGA infants are especially with the presence of catch-up growth hyperinsulinemia; Lniguez study showed catch-up growth in SGA individuals age3IGF-1levels compared with the same age, height and weight of infants matched for gestational age (AGA) rose significantly high, and associated with insulin resistance index. Also with the "catch-up growth leads to insulin resistance" inconsistent hypotheses findings,2001Stefran otherand others studies49(9.1±3.3years old) IUGR infants, using fasting glucose/fasting insulin ratio of insulin resistance index, the results show catch-up growth after birth no significant relationship between insulin resistance state and the results show that there is no significant relationship between insulin resistance and growth after birth.Chinese scholars have begun to concerns the relationship between SGA and insulin resistance, the experimental study of animal Deng Hong Zhu et al reveal whether or not there is catch-up growth, there showed insulin resistance in rats after SGA birth; Liu Zhan Li et al study found that infants with intrauterine growth restriction in the life early insulin sensitivity reduction and different degrees of insulin resistance; Deng Hong Zhu linear fashion youth research on early growth after birth, small for gestational age infants found early, the role of insulin growth factor may participate in the growth of catch-up SGA infants, the degree of insulin resistance and catch-up growth degree in hand.objectives:0-2years growth and development information and fasting insulin, fasting glucose, clear early gestational age of less than full-term infants catch-up growth, the rate of growth to catch up with the role of insulin resistance explore more appropriate catch-up growth rate, as term growth and development of small for gestational age infants early nutritional intervention to provide a basis to develop early intervention strategies. to lay the foundation for clinical and reduce this part of the metabolic syndrome in infants occur in adulthood.Methods:SGA study group from Shenzhen immediate kindergarten, Shenzhen MCH child health clinic in the examination of infants aged2-4. Inclusion criteria: gestational age of37-42weeks gestational age, birth weight less than the10th percentile with infants. Exclusion criteria:Subjects are required to exclude obesity, chromosomal disorders, congenital metabolic disease, hypothyroidism, growth hormone deficiency and growth retardation and other endocrine-related diseases, with congenital malformations and chronic organic diseases, there are nearly a year have a history of acute diarrhea in the previous month, or medical history of persistent diarrhea, recurrent respiratory infections and nearly three days of infusion history. Parents of infants with physical health, unaccompanied gestational diabetes during pregnancy.1:1matching methods, the date selected group of infants born with the case within one month away, the same sex that is appropriate for gestational age infants as a control AGA group, the immediate source of Shenzhen nursery examination appropriate for gestational age infants. Inclusion criteria:37-42weeks gestational age, birth weight for gestational age infants at the same average weight of10-90percentile into the first AGA group, there is no catch-up growth, the exclusion criteria. Both groups were signed by the guardian enrolled in the study after informed consent. Two groups of infants and anthropometric data was collection; fasting blood specimens from about4-5ml, respectively, glucose, insulin. Blood glucose concentration:The determination of peroxidase staining. Serum insulin determination: using immunoradiometric assay (IRMA) was measured. Z points by calculating the weight, height Z integral evaluation index, BMI, PI, height LS value, weight LS value, etc. physical growth of infants. And insulin resistance index (Homa-IR), fasting insulin sensitivity index (Homa-IAI), pancreatic β-cell function index (HBCI) and fasting glucose/fasting insulin ratio (G/I ratio).Data were analyzed using SPSS19.0statistical software, various outcome measures were carried normality test and homogeneity of variance test, the data do not conform to data conversion and then analyze the differences between the measured data set using paired t test, after conversion to still meet the conditions of the normal distribution and homogeneity of variance were to switch to a non-parametric test, to see whether there are differences between the two groups was statistically significant, with p<0.05was considered statistically significant. Pearson and spearman simple correlation analysis between variables were used.Results:1、The general data analysis SGA group and the AGA group birth weight, birth length, birth BMI, PI, birth weight Z score (WAZ birth) and birth length Z-score (HAZ born). SGA group were lower than the AGA group, the differences were statistically significant (p<0.05). After the growth and development of indicators grouped according to age analysis,2-year-old group, the3-year-old group, and the4-year-old group WAZ were greater than-2.2-year-old group SGA body weight, BMI, PI, WAZ were lower than the AGA group, height and HAZ is higher than the AGA group, BMI and HAZ difference was statistically significant (p<0.05).3-year-old group the SGA group were lower than AGA group, weight, BMI, PI, weight Z score (WAZ) differences were statistically significant (p<0.05); its length and height Z score (HAZ) difference no statistically significant (p>0.05);4-year-old group the SGA group were lower than AGA group, the difference was not statistically significant (p>0.05). 2、Analysis of early catch-up growth6months SGA group of HLS, Δ WAZ,Δ HAZ, Δ H, VH and Δ BMIZ were higher than in AGA group differences were statistically significant (p<0.05).12months,18months and24months of age when the HLS SGA group were higher than that of AGA group, the difference was statistically significant (p<0.05).3, Hematological indices analysis2-year-old group fasting glucose and fasting insulin concentration. SGA group fasting glucose, fasting insulin concentration, Homa-IR, HBCI were lower than AGA group, two groups of fasting insulin concentration, Homa-IR difference was statistically significant (p<0.05); while fasting blood glucose levels, HBCI difference was not statistically (p>0;05); Homa-IAI, G/I above the AGA group, Homa-IAI difference was statistically significant (p<0.05).Fasting plasma glucose concentration of3-year-old group SGA group, fasting insulin concentration, Homa-IR were lower than AGA group, the difference was statistically significant (p<0.05); Homa-IAI higher than AGA group, the difference was statistically significant (p<0.05); SGA group HBCI, G/I above the AGA group, the difference was not statistically significant (p>0.05).Fasting glucose concentrations4-year-old group SGA group than AGA group, fasting blood glucose concentration between the two groups was statistically significant (p<0.05); SGA group HBCI higher than AGA group, the difference was statistically significant (p<0.05); SGA group fasting insulin concentration, Homa-IR is higher than the AGA group, the difference was not statistically significant (p>0.05). SGA group Homa-IAI, G/I are lower than AGA group, the difference was not statistically significant (p>0.05).4、Correlation analysis of insulin resistance index2to3years old group of SGA infants0to6months,HLS, Δ HAZ, AH, VH and Homa-IAI were positively correlated;7to12months, ages13to18month,19to24months HLS and Homa-IAI were positively correlated.4years old group7-12months when the WLS, Δ WAZ, Δ W, VW, Δ H, VH was inersely associated with homa-ir were positively correlated;13-18months,19-24 months when the WLS was associated with homa-IR were positively correlated.Conclusion:1、Weight, height and PI value of the new born SGA will be lower than those of AGA due to Intrauterine Growth Retardation(IUGR).2、Catch-up growth tends to happen in the early age of the SGAs.3、There is a higher possibility for SGA to turn insulin sensitive to insulin resistance.4、The higher the catch-up growth rate of height, the higher the insulin sensitive index.5、The higher the catch-up growth rate of weight, the higher the insulin resistance index.6、It is direct, convenient and sensitive for LS value to represent SGA catch-up growth rate, which gained it an advantage comparing to the common methods. Therefore, we suggest that LS should be used in preliminary applications in clinic with the further research going on at the same time.