Background  There is a correlation between sedentary behaviors and depressive symptoms, but domestic research in this field is still insufficient.

Objective This investigation is designed to understand the relationships of mentally-active leisure sedentary behaviors (such as using computer and reading) or mentally-passive leisure sedentary behaviors (such as watching television) with depressive symptoms among middle-aged and elderly residents in China, and to provide a scientific basis for depression intervention.

Methods Based on a baseline survey of "Community-based Cohort Study on Nervous System Diseases" conducted in 2018-2019, the middle-aged and elderly people aged 55 years and above were selected from four provinces in China as study subjects. The information on average daily leisure sedentary time (watching TV, using computer, and reading) in the past year was collected through questionnaires, and depressive symptoms were evaluated by the 30-item Geriatric Depression Scale (GDS-30). Multiple linear regression was used to analyze the associations between different types of leisure sedentary time and GDS-30 score. Multiple logistic regression was used to analyze the risks of depressive symptoms related to different types of leisure sedentary time.

Results The mean GDS-30 score of selected 9514 middle-aged and elderly people was 4.8±4.1, and the positive rate of depressive symptoms was 7.4%. After adjusting for residence, age, gender, education, family income per capita, employment status, whether living alone, current smoking, regular drinking, dietary intake, obesity, disease history, physical activity, sleeping time, and other sedentary time, there were different correlations between different types of leisure sedentary time and depressive symptoms among the participants. For television related sedentary time, compared with the group of <2h·d^-1, the group of ≥ 6h·d^-1 was associated with a higher GDS-30 score, and the b was 1.19 (95%CI:0.62-1.75). For computer related sedentary time, compared with the group of 0 h·d^-1, the groups of >0-<2 h·d^-1 and ≥ 2 h·d^-1 were associated with lower GDS-30 scores, with bs of -0.59(95%CI:-0.86﹣-0.33) and -0.84 (95%CI:-0.23﹣-0.45) (P_trend<0.001), respectively, and were associated with lower risks of depressive symptoms, with ORs of 0.64 (95%CI:0.48-0.85) and 0.60 (95%CI:0.38-0.96) (P_trend <0.001), respectively. For reading related sedentary time, compared with the group of 0 h·d^-1, the groups of >0-<1 h·d^-1 and ≥ 1 h·d^-1 were associated with lower GDS-30 scores, with bs of -0.63(95%CI:-1.01﹣-0.24) and -0.64 (95%CI:-0.96﹣-0.22) (P_trend<0.001), respectively; and compared with the group of 0h·d^-1, the group of ≥ 1 h·d^-1 was associated with a lower risk of depressive symptoms, with an OR of 0.60 (95% CI:0.39-0.93) (P_trend=0.047). For total leisure sedentary time, compared with the group of <3h·d^-1, the groups of 3-<6h·d^-1 and ≥ 6h·d^-1 were associated with lower GDS-30 scores, with bs of -0.78 (95%CI:-0.96﹣-0.60) and -0.42 (95%CI:-0.73﹣-0.10) (P_trend<0.001), respectively, and were associated with lower risks of depressive symptoms, with ORs of 0.73 (95%CI:0.60-0.88) and 0.67 (95%CI:0.47-0.94) (P_trend < 0.001), respectively.

Conclusion There are varied correlations between different types of leisure sedentary behaviors and depressive symptoms among middle-aged and elderly people in China. Higher levels of mentally-active sedentary time (using computer or reading) are associated with lower depression scores and lower risks of depressive symptoms, but higher levels of mentally-passive sedentary time (watching TV) are associated with higher depression scores. The effect of total leisure sedentary time on depressive symptoms is correlated with the proportions of mentally-passive and mentally-active sedentary behaviors.