Impact of the great east Japan earthquake on the body mass index of preschool children: a nationwide nursery school survey.

OBJECTIVE:To evaluate the impact of the 2011 great east Japan earthquake on body mass index (BMI) of preschool children. DESIGN:Retrospective cohort study and ecological study. SETTING:Affected prefectures (Fukushima, Miyagi and Iwate) and unaffected prefectures in northeast Japan. PARTICIPANTS:The cohort study assessed 2033 and 1707 boys and 1909 and 1658 girls in 3 affected prefectures and unaffected prefectures, respectively, all aged 3-4 years at the time of the earthquake. The ecological study examined random samples of schoolchildren from the affected prefectures. PRIMARY AND SECONDARY OUTCOME MEASURES:The cohort study compared postdisaster changes in BMIs and the prevalence of overweight and obese children. The ecological study evaluated postdisaster changes in the prevalence of overweight children. RESULTS:1 month after the earthquake, significantly increased BMIs were observed among girls (+0.087 kg/m(2) vs unaffected prefectures) in Fukushima and among boys and girls (+0.165 and +0.124 kg/m(2), respectively vs unaffected prefectures) in Iwate. 19 months after the earthquake, significantly increased BMIs were detected among boys and girls (+0.137 and +0.200 kg/m(2), respectively vs unaffected prefectures) in Fukushima, whereas significantly decreased BMIs were observed among boys and girls (-0.218 and -0.082 kg/m(2), respectively vs unaffected prefectures) in Miyagi. 1 month after the earthquake, Fukushima, Miyagi and Iwate had a slightly increased prevalence of overweight boys, whereas Fukushima had a slightly decreased prevalence of overweight girls, compared with the unaffected prefectures. The ecological study detected increases in the prevalence of overweight boys and girls in Fukushima who were 6-11 and 6-10 years of age, respectively. CONCLUSIONS:These results suggest that in the affected prefectures, preschool children gained weight immediately after the earthquake. The long-term impact of the earthquake on early childhood growth was more variable among the affected prefectures, possibly as a result of different speeds of recovery.