BMC Pediatrics (Dec 2021)

25-Hydroxyvitamin D levels among 2-year-old children: findings from the Japan environment and Children’s study (JECS)

  • Limin Yang,
  • Miori Sato,
  • Mayako Saito-Abe,
  • Makoto Irahara,
  • Minaho Nishizato,
  • Hatoko Sasaki,
  • Mizuho Konishi,
  • Kazue Ishitsuka,
  • Hidetoshi Mezawa,
  • Kiwako Yamamoto-Hanada,
  • Yukihiro Ohya,
  • for the Japan Environment and Children’s Study (JECS) Group)

DOI
https://doi.org/10.1186/s12887-021-03005-3
Journal volume & issue
Vol. 21, no. 1
pp. 1 – 8

Abstract

Read online

Abstract Background The study aim was to obtain epidemiological data on vitamin D levels for the pediatric population in Japan. We assessed the prevalence of vitamin D deficiency and insufficiency in 2-year-old Japanese children using data from a large ongoing birth cohort study. Methods Data for analysis was obtained from the Japan Environment and Children’s Study (JECS) and a Sub-Cohort Study (SCS) of JECS. We evaluated the children’s serum 25(OH) D levels by 5th, 10th, 25th, 50th, 75th, 90th, and 95th percentiles, and the rates of vitamin D deficiency or insufficiency. We also presented a weighted prevalence rate for vitamin D deficiency or insufficiency among all children in JECS. Results After excluding children with missing 25(OH)D2 or 25(OH)D3 data, we analyzed 4655 remaining children, of whom 24.7% (95% CI, 23.5–26.0%) had vitamin D deficiency (< 20 ng/mL), and 51.3% (95% CI, 49.8–52.7%) were at risk of vitamin D insufficiency (20–30 ng/mL). The estimated prevalence of vitamin D deficiency and insufficiency among all children in JECS were 25.4% (95% CI, 24.1–26.7%) and 50.9% (95% CI, 49.4–52.4%). Vitamin D deficiency was found in 22.9% of boys and 26.5% of girls. Median serum 25(OH) D concentrations were lower among participants measured during winter and spring than among those measured in summer and autumn. The highest rate of vitamin D deficiency was observed in Hokkaido, the northernmost prefecture of Japan. Conclusion We analyzed data on serum 25(OH) D levels from a birth cohort study and found that vitamin D deficiency and insufficiency are very common among 2-year-old Japanese children. Sex, season, and latitude affect serum 25(OH) D concentrations.

Keywords