Body Index For Longitudinal Evaluation Of Physical Development Of Infant In Two Months

The superiority of body index for evaluation of physical development of infant has been realized by clinical and health care workers in pediatrics. The cooperation had reported the clinical importance of body index for longitudinal evaluation of physical development of infant. On the basis of that, a new body index aiming at features of infant was established to give comprehensive estimation on physical development of infants more reasonably and comprehensively. However, the former study aimed directly at appropriate-for-gestational age infant (AGA in short) mainly, which was composed of the premature, term infant and post-term infant. There was few study on large-for-gestational age infant (LGA in short) and small-for-gestational age infant (SGA in short) and it needed further supplement. Besides, the author carried out a study on 93 AGA infants in full term born in Dalian in 2005 and computed the value of ZLI, which verified the practicability of ZLI at present and provided preparation for adjusting standard in time.Objective1. To establish the longitudinal reference of eleven body indexes for infants in two months (including AGA, LGA and SGA) and provide reference standard for improving birth quality and child development.2. To verify whether ZLI can assess the physical development of LGA and SGA sensitively.3. To verify whether ZLI can assess the physical development of infant accurately nowadays.Methods: Calculated eleven body indexes of AGA, LGA and SGA. There were Quetelet Index(QI), Rohrer,s Ponderal Index(PI), VerverckIndex(VI), Pelidisi Index(PSI), BL-CR Index(BRI),Head Circumference/ Chest Circumference(HC/CC), Body Length/Head Circumference(BL/HC), crown-rump length/Head Circumference(CRL/HC),Mid-arm Circumference/ Head Circumference(MAC/HC),Chest Circumference/Mid-arm Circumference (CC/MAC) and ZLI, then did statistics by spss12.0. Each body index was compared by analysis of variance among groups by gestational age-body weight and among those at different time. Each body index was compared by t test between the sex groups. The rate of obesity was compared by chi square test among different cities.Results:1. The body solidity of each group all experienced a process from declining to increasing and the variation was in coincidence with the physiological body weight decline of infant after birth in regularity and time. It was proved that body index can reflect physical development of infant accurately.2. The growth of LGA was the slowest in three groups. SGA represented its catching-up growth just in one week postnatal and the upper part of body was faster. But on the end of two months, the body solidity of SGA was still inferior to that of AGA and LGA of the same age. Compared with the former study, the catching-up growth of SGA was slower than the premature. To a certain extent, the physical development of AGA was prior to that of LGA and SGA, which reflected the superiority of their body proportionality.3. The mean of ZLI for AGA, LGA and SGA from twelve cities in China at born was 0.99, 1.11 and 0.88 respectively, which was in accord with the physical development level of each group and with the evaluation result of the gold standard. ZLI can also assess the physical development of LGA and SGA accurately and doesn,t need correction at present.4. The mean of ZLI for AGA in full term was 1.02 at born in Dalian in 2005, while the formulary value was 1.00 for AGA in full term. However, the mean in Dalian was still in the normal reference range ( x±1s=1.00±0.06). ZLI can still be used for evaluation of physical development of infant nowadays.5. There was no difference for most body indexes between the sexes,although the girls held a little advantage.Conclusions1. Body index can compensate the shortage of single parameter and longitudinal study of body indexes can comprehensively assess the nutritional status, body proportionality and variation of physical development of infant much earlier. It can provide reference standard for clinical pediatrics and help improve birth quality and child development.2. Besides, the longitudinal study can contribute to earlier discovery of abnormal growth of infant. In this way the disease would be diagnosed and treated earlier by clinical workers.3. ZLI is an accurate index not only for evaluation of AGA but also for that of LGA and SGA and is of practicable value clinically.4. ZLI is still practicable but needs for correction according to the variability of infant features at born continually.