Alterations in physique among young children after the Great East Japan Earthquake: Results from a nationwide survey

Abstract

Background: Data for earthquake-related alterations in physique among young children in developed countries is lacking. The Great East Japan Earthquake caused severe damage in Iwate, Miyagi, and Fukushima Prefectures in northeastern Japan.

Methods: We retrospectively obtained anthropometric measurements in nursery school from 40,046 (cohort 1, historical control) and 53,492 (cohort 2) children aged 3.5-4.5 years without overweight in October 2008, and in October 2010, respectively. At the time of the earthquake in March, 2011, children in cohort 1 had already graduated from nursery school; however, children in cohort 2 were still enrolled in nursery school at this time. We compared the onset of overweight at 1 year after the baseline between children enrolled in their school located in one of the three target prefectures versus those in other prefectures using a logistic regression model, with adjustment for sex, age, history of disease, and obesity index at baseline. Overweight was defined as an obesity index of >+15%, which was calculated as (weight minus sex- and height-specific standard weight)/sex- and height-specific standard weight.

Results: The odds ratio (OR) for the onset of overweight in the three target prefectures was significant in cohort 2 (OR 1.25; 95% confidence interval [CI], 1.01-1.55) but not in cohort 1. When the two cohort were pooled (n = 93,538), the OR of the interaction term for school location × cohort was significant (OR 1.56; 95% CI, 1.09-2.23).

Conclusions: Incident overweight in young children was significantly more common in the three prefectures affected by the Great East Japan Earthquake than in other prefectures after the disaster.

Keywords: Childhood obesity; Earthquake; Physical growth; Tsunami.

Fig. 1

Map of Japan showing the epicenter of the Great East Japan Earthquake. Iwate, Miyagi, and Fukushima Prefectures were the areas most severely damaged by the earthquake.

Fig. 2

Study timeline. Study subjects in cohort 1 were young children born from April 2, 2004 to April 1, 2005, and were attending nursery school classes for 5-year-olds in 2010; cohort 1 did not experience the earthquake during their nursery schools days. In contrast, study subjects in cohort 2 were born from April 2, 2006 to April 1, 2007, and were attending nursery school classes for 5-year-olds in 2012; cohort 2 experienced the earthquake during their nursery schools days. Thus, cohort 1 was a historical control of the earthquake. The baseline survey for both cohorts was performed when the children were aged 3.5–4.5 years (i.e., in October 2008 for cohort 1 and in October 2010 for cohort 2). The follow-up survey was performed 1 year after baseline (i.e., in October 2009 for cohort 1, and October 2011 for cohort 2).