Table 5.

The relationship between sedentary behaviour and bone and skeletal health

No. of participants (No. of studies)	Design	Quality assessment				Absolute effect	Quality
		Risk of bias	Inconsistency	Indirectness	Imprecision
The mean age was 4.4 years. Data were collected cross-sectionally. Bone and skeletal health were assessed objectively using quantitative ultrasound.
1512 (1)	Cross-sectionala	Serious risk of biasb	No serious inconsistency	No serious indirectness	Serious imprecisionc	Objectively measured sedentary time: After adjusting for MVPA, accelerometer-derived sedentary time was no longer significantly associated with bone stiffness index (SI) in preschool children (β = -0.37; R2 = 19%; p = 0.28) [125]. Screen-based sedentary behaviours: There was no association between parent-reported screen time and SI (β = −0.04; R2 = 18.4%; p = 0.50) [125].	Very lowd

MVPA moderate-to-vigorous physical activity, SI bone stiffness index

^aIncludes 1 cross-sectional study that reported data from the Identification and prevention of dietary- and lifestyle-induced health effects in children and infants (IDEFICS) sample [125]

^bSerious risk of bias. Study participants were selected by “judgment sample”; questionable validity and reliability of subjective and objective exposure measures, and of quantitative ultrasound for measurement of bone stiffness in children [125]

^cSerious imprecision. It was not possible to estimate the precision of the findings since the study did not provide a measure of variability in the results

^dThe quality of evidence from the cross-sectional study was downgraded from “low” to “very low” because of: (1) a serious risk of bias that diminished the level of confidence in the observed effects, and (2) serious imprecision