Hokkaido birth cohort study in Japan on the growth trajectory of children born with low birth weight until 7 years of age

• DOI: 10.1016/j.earlhumdev.2023.105925
• Publication Date: 2023-12-26T07:03:34Z
• Authors: Kritika Poudel; Sumitaka Kobayashi; Hiroyoshi Iwata; Maki Tojo; Takeshi Yamaguchi; Keiko Yamazaki; Naomi Tamura; Mariko Itoh; Taku Obara; Shinichi Kuriyama; Reiko Kishi
• Keywords: Cohort Studies; Japan; Pregnancy; Infant, Newborn; Humans; Infant; Birth Weight; Female; Pregnant Women; Infant, Low Birth Weight; Child

Low birth weight (LBW) is a significant global health concern with potential health risks and developmental implications for infants. Catch-up growth, an accelerated growth following an inhibition period, may partially compensate for growth deficits in LBW children.This study investigated the prevalence of LBW and catch-up growth in height, weight, and body mass index (BMI) among LBW children in Japan, identified factors associated with LBW, and explored the potential for catch-up growth at different ages up to seven years.The Hokkaido birth cohort study included 20,926 pregnant Japanese women recruited during their first trimester from 37 hospitals and clinics. Follow-up assessments were conducted in children up to seven years of age, tracking LBW children's growth and development using the Maternal and Child Health Handbook, and providing valuable insights into catch-up growth patterns.LBW was defined as a neonatal birth weight of <2500 g. The primary outcomes were catch-up growth in height, weight, and BMI at different ages. Z-scores were calculated to assess growth parameters with catch-up growth, defined as a change in z-score (> 0.67) between two time points.A LBW was prevalent in 7.6 % of the cohort, which was lower than that reported in other Japanese studies. Among LBW children, 19.3 % achieved catch-up growth in height by age seven, and 10.6 % in weight. Catch-up growth in LBW children could partially offset these deficits. Further research will help understand the long-term outcomes and inform interventions for healthy development.