Physical and socioeconomic predictors of birthweight in Japan.

BACKGROUND: The purpose of this study was to characterize physical and socioeconomic factors associated with birthweight in Tokyo, Japan. METHODS: In a cohort of obstetric outpatients from the Tokyo Metropolitan Maternity and Child Health Institute, Tokyo, and The Jikei University School of Medicine, Chiba, Japan, 553 eligible women in their third trimester of pregnancy were given a survey investigating physical and socioeconomic backgrounds. RESULTS: Infants tended to be small for gestational age when maternal pre-pregnancy weight was lower, and low income and female infant gender were significantly associated with a low birthweight infant. Further, birthweight compared with predicted birthweight was lower in the case of a female infant gender, low income, low maternal pre-pregnancy weight and low parity. CONCLUSION: Income is a novel parameter that is associated with birthweight in Japan.

Problematic behaviours of 3-year-old children in Japan: relationship with socioeconomic and family backgrounds.

AIM: The purpose of our study was to elucidate factors in socioeconomic and family backgrounds of 3-year-old children in Tokyo, Japan that were associated with problematic behaviours among the children. STUDY DESIGN: 670 eligible 3-year-old children underwent an evaluation of problematic behaviour by the Japanese Child Behaviour Checklist (CBCL/2-3) and of socioeconomic and family backgrounds. RESULTS: Stepwise multi-logistic regression analyses using all 28 variables showed that longer hours watching TV, smoking during pregnancy, coffee drinking during and after pregnancy increased, whereas higher family income, a larger number of older brothers/sisters, higher educational level of father decreased problematic behaviours. Maternal anxiety measured by trait anxiety using the STAI was associated with behaviour problems measured by CBCL, particularly with externalizing domains composed by aggressiveness, oppositional and attention domains. CONCLUSION: These results suggest that problematic behaviours among children may be increased by adverse socioeconomic and family backgrounds that may be associated with maternal anxiety.

[Retinopathy of prematurity in extremely low birth weight infants: a Tokyo multicenter study].

OBJECTIVE: To investigate how the increase in survival rate in extremely low birth weight (a birth weight of 1,000 g or less) infants had affected the incidence of retinopathy of prematurity (ROP) and the frequency of laser treatment. METHODS: We retrospectively reviewed the medical records of 122 surviving premature infants with birthweights less than 1,000 g to determine the severity of ROP observed at 16 neonatal intensive care units in Tokyo between April and October 2002. RESULTS: The survival rate was 85.6%. The mean gestational age was 26.74 weeks and the mean birth weight was 782.25 g. One-hundred-and-five infants (86.1%) developed ROP, fifty (41.0%) received laser treatment, and six (4.9%) had retinal detachment. The median postmenstrual age (gestational age at birth plus chronological age in weeks, PMA) at the onset of ROP was 32.5 weeks, and the first laser treatment was performed at the median PMA of 35.7 weeks. CONCLUSIONS: In these extremely low birth weight infants, there was an increase in the survival rate and in the incidence of severe ROP that progressed to the stage that required treatment.

Visual feature binding in early infancy.

How does the developing brain of the human infant solve the feature-binding problem when visual stimuli consisting of multiple colored objects are presented? A habituation--dishabituation procedure revealed that 1-month-old infants have the ability to discriminate changes in the conjunction of a familiar shape and color in two objects. However, this good earlier performance was followed by poorer performance at 2 months of age. The performance improved again at 3 months of age. Detailed analysis of the oculomotor behaviors revealed that the age of 2 months was a period of drastic transition when the tendency to stay with the fixated objects disappeared and repetitive saccades between the two objects emerged. Our findings suggest that the ability to perceive conjunctions of features is available to infants very early, that the perceptual/neural basis at 1 and at 3 months of age may be fundamentally different, and that feature integration by vigorous eye movements or selective attention may be the key functional difference between the age groups.