Combinations of physical activity, sedentary time, and sleep duration and their associations with depressive symptoms and other mental health problems in children and adolescents: a systematic review

Table 2 Combinations of physical activity, sedentary time, and sleep duration and their relationships with depressive symptoms

No of studies	Design	Quality assessment					No of participants	Absolute effect	Quality
No of studies	Design	Risk of bias	Inconsistency	Indirectness	Imprecision	Other	No of participants	Absolute effect	Quality
3	Cross-sectional study^a	Serious risk of bias^b	No serious inconsistency	No serious indirectness	No serious imprecision	None	84,004	MEETING ALL 3 RECOMMENDATIONS [18, 19, 39] 3/3 studies found that meeting all 3 recommendations (compared with meeting none) was associated with lower odds of depressive symptoms among male and female adolescents [18, 19] but not children [39]. DIFFERENT COMBINATIONS OF PHYSICAL ACTIVITY + SEDENTARY BEHAVIOUR + SLEEP [39] 1/1 study found that meeting all three recommendations was associated with significantly lower odds of depression among adolescents compared with meeting none, one, or any combinations of two recommendations among adolescents. However, among children, meeting the screen time recommendation alone, both the screen time and sleep duration recommendation, or both the physical activity and sleep duration recommendations was associated with lower odds of depression than meeting none or all three guidelines.	VERY LOW

Age ranged between 6 and 20 years, and all data collection was cross-sectional
^aIncludes 3 cross-sectional studies [18, 19, 39]
^bAll studies used a subjective assessment of movement behaviours with no psychometric properties reported, except one study that measured physical activity by accelerometer [19]. Depression was measured differently across studies, with only one study that used a validated instrument [19]; one study [18] used an item that asked students if they felt sad or hopeless almost every day for two weeks or more in a row in the past year; another study [19] used the Mood and Feelings questionnaire (MFQ), a reliable and valid measure of depression in children, and another study [39] used parents’ response (“currently have condition”) to the question asking if they had ever been told by a health care professional that the child had the condition, and whether the child currently has depression. Therefore, the quality of evidence was downgraded from “low” to “very low” due to a serious risk of bias

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