Accelerometer-Measured Diurnal Patterns of Sedentary Behavior among Japanese Workers: A Descriptive Epidemiological Study

Abstract

Increased sedentary behavior (SB) can adversely affect health. Understanding time-dependent patterns of SB and its correlates can inform targeted approaches for prevention. This study examined diurnal patterns of SB and its sociodemographic associations among Japanese workers. The proportion of sedentary time (% of wear time) and the number of breaks in SB (times/sedentary hour) of 405 workers (aged 40-64 years) were assessed using an accelerometer. SB patterns and sociodemographic associations between each time period (morning, afternoon, evening) on workdays and nonworkdays were examined in a series of multivariate regression analyses, adjusting for other sociodemographic associations. On both workdays and nonworkdays, the proportion of sedentary time was lowest in the morning and increased towards evening (b = 12.95, 95% CI: 11.28 to 14.62; b= 14.31, 95% CI: 12.73 to 15.88), with opposite trend for breaks. Being male was consistently correlated with SB. Other sociodemographic correlates differed depending on time-of-day and day-of-the-week. For instance, desk-based workstyles and urban residential area were associated with SB during workday mornings and afternoons, being single was related to mornings and evenings, workdays and nonworkdays. Initiatives to address SB should focus not only on work-related but time-of-day contexts, especially for at-risk subgroups during each period.

Keywords: accelerometer; daily patterns; sitting time; sociodemographic correlates.

Figure 1

The flowchart of participant recruitment.

Figure 2

Diurnal patterns of sedentary behavior by sociodemographic group. SB—sedentary behavior. The interaction effects of the proportion of sedentary time between subgroups of each sociodemographic variable were examined using multilevel mixed-effects linear regression, and stratified analysis was conducted for variables that showed significant interactions: (a) Workday SB by education attainment; (b) Workday SB by employment status; (c) Workday SB by workstyle; (d) Workday SB by alcohol consumption; (e) Workday SB by residential area; (f) Nonworkday SB by educational attainment; (g) Nonworkday SB by workstyle; (h) Nonworkday SB by alcohol consumption; (i) Nonworkday SB by age. The values were expressed as means and 95% confidence intervals.