A Study On Cognitive Development, Temperament And Behavior Problems In Low Birth Weight Children Aged 2～3 Years Old

Objective: To explore the effects of low birth weight on cognitive development,temperament and behavior problems in children aged 2-3 years old.Methods: Cognitive development, temperament and behavior problems wereexamined in 50 low birth weight (LBW) children, and 380 normal birth weight (NBW) children. Outcome at age during 2-3 years old was assessed with the self-made questionnaire of influential factors, the Bayley Scales of Infant development (Mental Developmental Index [MDI], Psychomotor Developmental Index [PDI] ) , toddler temperament questionnaire and Achenbach' s child behavior checklist. Statistical analyses were performed by SPSS 11.5 Software after classifying according to birth weight distinction. The 5% significance level was used for all the analyses.Results: (1)Cognitive development: LBW children were more likely to have lowermean MDI(97.36 vs. 106.32, P<0.01) and lower mean PDI(99.84 vs. 104.86, P<0.05 ) than NBW children. The proportion of children who scored within the abnormal range (<85 ) were as follows: In LBW children, 10(20%) of MDI were abnormal; while 4(8%) of PDI were abnormal. In NBW children, 1(2%) of MDI was abnormal, while 1(2%) of PDI was abnormal. The proportion of children who scored within the excellent range ( 115) were as follows: In LBW children, 13(26%) of MDI were excellent; while 3(6%) of PDI were excellent. In NBW children, 10(10%) of MDI were excellent, while 10(10%) of PDI were excellent. All changes observed in LBW children and NBW children indicate better cognitiveperformance in NBW children. However, after adjustment for multiple regression analyses including other influential factors, LBW was not associated with poor cognitive outcome. Coefficients of congruence were observed between MDI and family income, PDI and delivery, respectively. (2)Temperament: Independent t-tests identified that NBW children were significantly more active than LBW children(t=2.192,P=0.029). There were no differences among other temperament dimensions. 44.9% of the studied populations were intermediate children, 49.3% were easy pattern, 4.2% were difficult pattern, and 1.6% were slow-to-warm pattern. In LBW children, 46% were intermediate children, 48% were easy pattern, 4% were difficult pattern, 2% were slow-to-warm pattern. In NBW children, 44.7% were intermediate children, 49.5% were easy pattern, 4.2% were difficult pattern, 1.6% were slow-to-warm pattern. No difference of temperament distributing between LBW children and NBW children (P=0.943) was found. (3)Behavior problems: The rate of child behavior disorder accounted for 15.3%. In all children investigated, 2.3% of the studied children were social withdrawal, 2.3% were depressed, 1.4% were sleep problems, 11.4% were somatic problems, 0.9% were aggressive, 1.4% were destructive, 5.6% were total score. 12(24%) of LBW children had behavior problems, while 54(14,21%) of NBW children had behavior problems. Independent t-tests identified that NBW children had more sleep problems than LBW children(t=2.200,P=0.031). There was significant difference between LBW and NBW children in social withdrawal ( x 2=5.427,P=0.02). Scores of behavior problems (including social withdrawal, depressed, somatic problems, aggressive, destructive and total score) were higher in LBW children than those in NBW children, though no significant difference was found (P=0.06~0.112) . In all these studied groups, difficult pattern children had more behavior problems in sleep problems, aggressive, destructive and total score.Conclusions: NBW children were significantly much better than LBW children in MDI and PDI. There is no difference between LBW and NBW children in thedistribution of temperament pattern. The significant difference can be found between the incidences of LBW and NBW children behavior problems. In all these studied groups, there was a correlation between temperament pattern and sleep problems, aggressive, destructive and total score.