Association of the COVID-19 pandemic with changes in objectively measured sedentary behaviour and adiposity

Background Several studies have reported that the coronavirus disease (COVID-19) pandemic has increased sedentary behaviour and obesity; however, these analyses used self-reported data, and the association between sedentary behaviour and visceral fat and adipocytokines during the COVID-19 pandemic remains unclear. We aimed to investigate the association of the COVID-19 pandemic with objectively measured sedentary behaviour and these obesity-related factors. Methods Longitudinal analysis was conducted on 257 Japanese participants who underwent health check-ups in 2018 before and in 2020 during the COVID-19 pandemic. For both time points, sedentary behaviour was measured using an accelerometer for at least 7 days, visceral fat area (VFA) was measured using abdominal bioelectrical impedance analysis, and blood adiponectin level was measured using latex agglutination turbidimetric immunoassay. Multiple linear regression was performed to determine the association between sedentary behaviour and these outcomes. Results Compared with data in 2018, sedentary behaviour and VFA were significantly increased ( P < 0.001, P = 0.006) whereas adiponectin level was significantly decreased ( P < 0.001) in 2020. Increased sedentary behaviour was significantly associated with an increase in VFA (β = 3.85, 95% CI 1.22–6.49, P = 0.004) and a decrease in adiponectin level (β = −0.04, 95% CI −0.06 to −0.01, P = 0.005). However, the association of sedentary behaviour with adiponectin level was not significant after considering the effects of VFA. Conclusions The COVID-19 pandemic was associated with objectively measured sedentary behaviour and obesity-related factors in Japanese adults. Additionally, an increase in sedentary behaviour was associated with an increase in VFA, whereas the association of sedentary behaviour with adiponectin was partly mediated by VFA. These results suggest that avoiding increasing sedentary time is important to prevent visceral adiposity thereby ameliorating adiponectin, especially during behavioural limitations such as the COVID-19 pandemic.