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.

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.

[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.

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.