Table 4.

Demographic and biological correlates of mobile screen media use and direction of association

Variable type	Variables	Smartphones		Tablets		Touch screens		Any media device
		Association	Study	Association	Study	Association	Study	Association	Study
Child biological and demographic factors	Child age	+	31	+	31 33	0	30	+	27 34 36 38
		− (co-use)	1	− (co-use)	1
	Child sex (0=boy)	0	1	0	1	0	30	+	32 38
	BMI							0	27
Family biological and demographic factors	Parental age	0	1	0	1 33			0	27
								−	36
	Parent’s sex (0=father)	0	1	0	1	0	30
	Family income			0	33	+	30	0	32
								+	38
								−	36
	Parent’s occupation (0=unemployed)							−	36
	Parent’s education	0	1	0	1 33	0	30	0	32
	Language							0	27
	Race/ethnicity	+ (non-Hispanic)	1	+ (Hispanic)	1			0	27
								− (European-Canadian-Caucasian)	32
	Country of birth							0	32 38
Family structure factors	Family size					0	30
	Number of children in the family							+	36

Touch screens include combined results for smartphones and tablets while any media includes combination of traditional media with at least one form of mobile screen media devices.

‘+’ denotes positive association, ‘−’ denotes negative association, ‘0’ denotes no association (significant at 95% confidence level, p<0.05), empty cells denote association for that variable has not been studied.

BMI, body mass index.