Association between economic status and body mass index among adolescents: a community-based cross-sectional study in Japan

Abstract

BackgroundChildhood overweight and obesity is a growing health challenge in Japan and might be associated with childhood poverty.We aimed to investigate the association between low economic status and body mass index (BMI) and to reveal the mediators of this association among junior high school students in Japan.MethodsJunior high school students (N = 2968) from two cities in Shizuoka, Japan, were surveyed. Questionnaires assessed subjective economic status, weight, and height. Economic status was categorized into low and non-low, and BMI z-scores were calculated using the WHO Growth Reference. Multivariate regression analyses were conducted to determine the association between economic status and BMI z-scores, adjusted for covariates and stratified by gender.ResultsAmong girls, low economic status was significantly positively associated with BMI z-scores in the crude model (coefficient: 0.35; p = 0.001). In a model adjusted for breakfast skipping, the coefficient of economic status decreased by 28.57 % but remained significant (coefficient: 0.25; p = 0.017). In the final model adjusted for other possible covariates, low economic status remained significantly positively associated with BMI z-score (coefficient: 0.22; p = 0.044). The same association was not found for boys.ConclusionsLow economic status was positively associated with higher BMI among girls in junior high school in Japan, but this was not true for boys. Childhood poverty might be associated with overweight and obesity among adolescent girls in Japan. Health policies at junior high schools to discourage breakfast skipping might be effective for countering the association between childhood poverty and overweight in adolescent girls.Electronic supplementary materialThe online version of this article (doi:10.1186/s40608-016-0127-z) contains supplementary material, which is available to authorized users.

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“…However, Japan also represents a society that has undergone significant economic reforms and reduction in childhood poverty. Relative child poverty in Japan is currently estimated at 16% compared with over 40% reported in the current study in post-war Japan (Mizuta et al, 2016). More recent socio-economic reforms can be observed in certain European countries.…”

Relationship between Obesity and Oral Health Behavior in Primary and Junior High School Students: A Cross-sectional Study

“…This study had several limitations. For example, it was not possible to investigate the relationship between socio-economic factors and childhood obesity, even though previous reports have found a link between the two 6,13) . Additionally, the study participants were not selected randomly, which may have led to selection bias.…”

Subjective Household Economic Status and Obesity in Toddlers: A Cross-Sectional Study of Daycare Centers in Japan

“…The present study adopted subjective household economic status, but did not include the amount of household income as the exposure. Although subjective assessment of household economic status is assumed to be useful, 9 , 23 it is not an objective evaluation and not based on a quantitative cut-off value. Furthermore, the method for measurement of height and weight was not strictly defined (eg, instruments used, measurement date, or measurement time).…”

“…10 Subjective household economic status has been used to assess poverty status in preliminary research. 9 , 11 , 12 Subjective household economic status is an indicator of satisfaction with one’s life situation or with life domains, such as income, health, leisure time, environment, or social integration. 13 In a previous study to compare the explanatory power of objective and subjective economic status on perceived life quality measures, subjective economic status accounted for more variance in life quality measures than did objective economic status (income).…”

“…5 – 7 Indeed, recent Japanese cross-sectional studies have reported that lower household economic status (income or subjective economic status) is a risk factor for obesity in adolescents. 8 , 9 This increased risk may be problematic not only in school-age children, but also at earlier life-stages (ie in pre-school children). Despite these concerns, the association between household economic status and obesity in toddlers has not been clarified.…”