Geographical Differences in the Population-Based Cross-Sectional Growth Curve and Age at Peak Height Velocity with respect to the Prevalence Rate of Overweight in Japanese Children

Abstract

The School Health Examination Survey is a nationwide examination carried out annually in Japan, and the results are entered into a prefectural-level physical measurement database. We used this database to determine the geographical differences in a population-based cross-sectional growth curve and investigated the association between age at peak height velocity (PHV) and the prevalence rate of overweight in children among Japanese prefectures. Mean prefectural-level age at PHV was estimated by the cubic spline-fitting procedure using cross-sectional whole-year prefectural mean height data (5–17 years, 2006–2013), and 8-year (2006–2013) means of the standardized prevalence rates of overweight children and other anatomical data (8-year standardized weight and height) were recalculated. Mean prefectural age at PHV was more strongly correlated with the mean prefectural prevalence rate of overweight (age 5–8 years) than with other weights or heights in both sexes. On the basis of these findings and their confirmation by multiple regression analysis, the prevalence rate of overweight was selected as a primary factor to explain the geographical difference in age at PHV. These findings suggest that childhood overweight is a dominant factor responsible for the observed geographical differences in onset of puberty in Japan.

Pubertal height gain is inversely related to peak BMI in childhood

“…However, most other non-American studies support our findings, with earlier onset of puberty in overweight/ obese boys; in the 1940s, under-nutrition was reported to delay onset of puberty and Mossberg found earlier puberty in obese Swedish boys. These findings were confirmed in the United Kingdom (18), and later in many European counties (19,25,30), and Japan (31). Correlation between BMI and mid-puberty was also seen for boys in a UK study, which found a linear correlation between BMI SDS in childhood and age at PHV (30).…”

Prolonged elevated body mass index in preschool children after the Great East Japan Earthquake

“…Second, there are regional differences in growth in Japan, although Japanese people are generally considered ethnically homogeneous. Children in the Tohoku district are more obese than those in other areas in Japan . Therefore, we analyzed the data with several methods.…”

“…We defined the former and the latter groups of children as the historical control and exposure groups, accounting for 4.9% and 6.3% of the number of births in Japan during the same period, respectively. 14 Because it has been reported that children in the Tohoku district were more likely to be obese than those in other Japanese areas, 15,16 and the disaster had inflicted severe damage on the Pacific Ocean-side of the Tohoku district (Fukushima, Miyagi, and Iwate Prefectures), we analyzed data within the Tohoku district (Aomori, Akita, Yamagata, Fukushima, Miyagi, and Iwate Prefectures) by dividing the district into two groups: the severely damaged and the control areas ( Fig. S2).…”

Design of the health examination survey on early childhood physical growth in the Great East Japan Earthquake affected areas

“…Previous studies have reported that children in the northeast (Tohoku) region were more likely to be overweight than those in other areas in Japan 15, 16, 17, 18. Considering regional variations in physical growth, we selected preschool children residing in the other three prefectures within the Tohoku region as a control group.…”