A study by Assistant Professor KYAN Akira (Department of Social Epidemiology, Graduate School of Medicine and School of Public Health, Kyoto University; while conducting the study, Graduate School of Human Development and Environment, Kobe University) and Professor TAKAKURA Minoru (Health Promotion & Development / School Health Division, Faculty of Medicine & Graduate School of Health Sciences, University of the Ryukyus) found for the primary time that socioeconomic inequality in achieving beneficial physical activity levels amongst Japanese youth increased while difference in breakfast intake decreased throughout the COVID-19 pandemic in comparison with levels before the pandemic.

The outcomes of this study were published within the Journal of Physical Activity & Health on April 22, 2023.

Key findings

• This study is the primary worldwide to research time trend in socioeconomic inequality in various health behaviors amongst adolescents before and throughout the COVID-19 pandemic.
• The study found widening socioeconomic inequality amongst Japanese adolescents in achieving beneficial physical activity levels before and throughout the pandemic, alongside narrowing inequality in breakfast intake. Specifically, despite no observed differences in physical activity by income in 2019, by 2021, adolescents from families with lower equivalent household incomes were less likely to interact in physical activity.
• Research is required to proceed monitoring the impact these phenomena could have on health over the medium to long run.

Research background

The research team has previously identified socioeconomic inequality in physical activity amongst Japanese adults throughout the COVID-19 pandemic (Kyan & Takakura, Public Health, 2022). This study focused on the difficulty of socioeconomic disparities in adolescent health behavior. Health inequality in Japan has been moderate in comparison with Western countries, however the situation has worsened recently, pushing the federal government to take motion since 2013. The disparities in health behaviors observed in Western countries are based on the economic status of households and neighborhoods, however the situation in Japan shouldn’t be well understood because such inequality has only recently begun to draw attention in Japan.

Through the COVID-19 pandemic, adolescent health behaviors deteriorated worldwide. National studies in Japan have also shown worsening health behaviors, including a marked decrease in physical activity and a rise in screen time. Researchers have also identified the chance that the pandemic may exacerbate health disparities by increasing household income inequality.

This study aimed to discover trends in socioeconomic disparities within the health behaviors of Japanese adolescents before and throughout the COVID-19 pandemic, particularly in basic health behaviors, including physical activity, screen time, breakfast intake, and bowel movement frequency. The hope is that understanding these disparities will result in developing intervention strategies and policies to supply youth with needed support.

Study summary

The study used data from the 2019 and 2021 National Sports-Life Survey of Children and Young People conducted by the Sasakawa Sports Foundation. The survey focuses on children and youth’s after-school and weekend exercise and sports participation, sports environments, and health behaviors corresponding to sleep duration, media usage time, and bowel movement frequency. Data were collected from June to July each survey 12 months using self-administered questionnaires from adolescents and their parents/guardians. Survey participants were chosen using a two-staged stratified random sampling method from 225 sites proportionally distributed from the strata by district and city size based on the population of the Basic Resident Registers. The survey included 3,000 individuals aged 4–21.

The study’s evaluation included adolescents aged 12–18 and excluded 18-year-olds who didn’t attend highschool. The variety of participants who met the inclusion criteria for age and faculty enrollment was 1,076 for 2019 and 1,025 for 2021. After excluding individuals with missing variables, the research team analyzed data for 766 and 725 individuals in 2019 and 2021.

The research team used equivalent household income as a measure of socioeconomic status. In accordance with accepted health guidelines, favorable health behaviors were defined as every day moderate to vigorous physical activity (MVPA) of not less than 60 minutes, screen time (ST) of lower than 2 hours, sleep of 8 to 10 hours, every day breakfast intake, and bowel movement frequency of not less than once in every 3 days.

This study is exclusive in that it used slope and relative indices of inequality to account for differences in the proportion of the population in each category of socioeconomic factor (on this study, income).

The evaluation found widening socioeconomic inequality amongst Japanese adolescents in achieving beneficial physical activity levels before and throughout the pandemic, alongside narrowing inequality in breakfast intake. Specifically, despite no observed differences in physical activity by income in 2019, by 2021, adolescents from families with lower equivalent household incomes were less likely to interact in physical activity. There was a trend toward a narrowing gap for screen time, however it was not statistically significant. No socioeconomic disparities were observed for sleep duration and defecation frequency in each 2019 and 2021.

Future developments

Continued monitoring is required to find out whether measures to advertise physical activity before the COVID-19 pandemic also contributed to the reduction of widening socioeconomic disparities. The incontrovertible fact that this study revealed differences in physical activity amongst adolescents depending on their socioeconomic status underpins the importance of continued health (and health behavior) monitoring. This study guarantees to function a reference for considering policy directions.

Source:

Journal reference:

Kyan, A &Takakura, M.,(2023) Impact of the COVID-19 Pandemic on the Socioeconomic Inequality of Health Behavior Amongst Japanese Adolescents: A 2-12 months Repeated Cross-Sectional Survey. Journal of Physical Activity and Health. doi.org/10.1123/jpah.2022-0489.