Cross-sectional associations between 24-hour time-use composition, grey matter volume and cognitive function in healthy older adults

Table 1 Participant demographics

		Total (n = 378)
		Mean ± SD	Range (min, max)
Age	65.6 ± 3.0		60.1, 71.2
Sex (%)	Female	255 (67%)	-
Sex (%)	Male	123 (33%)	-
	Education (years)	16.6 ± 3.2	7, 30
Accelerometer waking wear time (valid files only; mins)		936.6 ± 56.5	756.5, 1106.8
Arithmetic means of time-use behaviours (min/day)	MVPA	90.6 ± 47.0	3.4, 301.7
	LPA	178.6 ± 50.6	57.9, 342.6
	SB	667.4 ± 91.5	410.3, 982.3
	Sleep	501.8 ± 58.5	330.8, 741.0
Compositional means of time-use behaviours (min/day)	MVPA	90.7 ± 47.1	3.4, 301.7
	LPA	178.8 ± 50.7	57.8, 346.6
	SB	668.2 ± 92.2	410.8, 968.1
	Sleep	502.2 ± 57.5	331.4, 712.5
Brain volume (ml)	TIV	1551.0 ± 141.2	1202.0, 2279.0
	Global GM	596.0 ± 50.8	466.3, 843.0
	Temporal lobe	95.3 ± 9.2	67.4, 130.9
	Hippocampus	6.2 ± 0.6	4.6, 8.5
	Lateral ventricles	25.0 ± 12.5	6.0, 84.5
	Frontal lobe volume	168.0 ± 16.9	127.0, 240.0
	WMH	1.9 ± 3.4	0.0, 33.7

Note: Values are presented in the “Mean ± SD” column as either mean ± SD for numeric variables or count (percentage) for categorical variables. Range data represents minimum and maximum values. MVPA = moderate-vigorous physical activity; LPA = light physical activity; SB = sedentary behaviour; TIV = total intracranial volume; GM = grey matter; WMH = white matter hyperintensities. Volumetric data are presented in raw form (i.e., prior to adjusting for site, total intracranial volume and use of distortion correction during imaging). ‘Arithmetic means’ represent the average minutes of time spent in each behaviour before applying the closure function. ‘Compositional means’ represent the geometric average of time use values after applying the closure function (closing composition to sum up to 1440 minutes).

ISSN: 1479-5868