Peri-Pubertal Height Shifts and Stable Photoperiod-Associated Geographic Patterning Before and After COVID-19 in Japanese Children.

Authors

Masana Yokoya

Published in

American journal of human biology : the official journal of the Human Biology Council. Volume 38. Issue 7. Pages e70306.

Abstract

Geographic variation in child body size in Japan has previously been associated with effective day length, a light-related measure. We tested whether this prefecture-level geographic structure remained stable across the COVID-19-related disruption.
We conducted a prefecture-level ecological analysis using repeated cross-sectional summaries from Japan's School Health Statistics. For each sex and single-year age from 5 to 17 years, we compared a pre-pandemic baseline (2017-2019 mean) with a post-disruption period (2024-2025 mean). Effective day length above 5000 lx (ED5000) was treated as a prefecture-fixed exposure. Mean height was modeled as a function of mean weight and ED5000, and slope stability was tested using pooled models with an ED5000-by-period interaction term.
Across ages 5-17 years in both sexes, mean height was generally higher in the post-period than in the pre-period, and mean weight also showed an upward shift across most ages, with the largest increases around peri-pubertal ages. ED5000 remained negatively associated with height conditional on weight in both periods, and there was no evidence that the ED5000-associated slope changed between periods at any age in either sex. In contrast, post-period differences in height appeared mainly as age-dependent upward shifts concentrated around peri-pubertal ages, peaking at ages 10-11 years in girls and 12-13 years in boys.
These findings suggest that COVID-era disruptions were followed by age-specific increases in body size around puberty, consistent with changes in maturation tempo. In contrast, the ED5000-height association remained stable. Thus, period-related growth shifts occurred within a persistent geographic structure.

PMID:
42400118
Bibliographic data and abstract were imported from PubMed on 04 Jul 2026.

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