Sedentary time in a nationally representative sample of adults in Japan: Prevalence and sociodemographic correlates.

Sedentary behaviour is associated with risks of detrimental health outcomes. It is crucial to understand how much time people spend in sedentary behaviour and what factors affect too much sedentary time for effective intervention. However, few studies examined the prevalence and the correlates of sedentary behaviour in Japan. Therefore, we assessed total sedentary time and its sociodemographic correlates using a nationally representative sample of adults in Japan. Cross-sectional data from Sports-Life Survey in 2016 and 2018 conducted by Sasagawa Sports Foundation was used. Participants' sociodemographic factors and total sedentary time were collected by questionnaires. We classified those with <8 h/day of total sedentary time as "low-sedentary" and those with ≥8 h/day of total sedentary time as "high-sedentary". A multiple logistic regression model was applied to calculate adjusted odds ratios and 95% confidence intervals (95% CIs) for the association of each variable with the "high-sedentary" group (≥8 h/day). In total, 5,346 participants were included in the analyses. On average, time spent in sedentary behaviour was 5.3 h/day (SD = 3.7) among Japanese adults. The percentage of "high-sedentary" was 25.3% (95% CI: 24.1-26.4) and higher body mass index (≥25 kg/m), being unmarried, unemployment, and higher educational level (graduate school or university) were positively associated with being "high-sedentary". In conclusion, higher sedentary time was among people with higher body mass index, being unmarried, unemployed, and higher education. Intervention for reducing sedentary time should be developed, targeting people with these characteristics.