Tracking of TV and video gaming during childhood: Iowa Bone Development Study

Table 1 Participant Characteristics

	Age 5		Age 8		Age 11		Age 13
	Boys	Girls	Boys	Girls	Boys	Girls	Boys	Girls
	(n = 205)	(n = 229)	(n = 193)	(n = 222)	(n = 171)	(n = 211)	(n = 168)	(n = 189)
Age (yr)	5.2 ± 0.4	5.3 ± 0.5*	8.7 ± 0.6	8.7 ± 0.6	11.2 ± 0.3	11.2 ± 0.3	13.3 ± 0.4	13.3 ± 0.4
Height (cm)	112 ± 6	111 ± 6	134 ± 7*	132 ± 7	149 ± 8	149 ± 8	163 ± 10*	160 ± 7
Weight (kg)	21 ± 4	20 ± 4	33 ± 10	32 ± 9	45 ± 13	44 ± 12	58 ± 16	56 ± 15
Fat Mass (kg)	3.9 ± 2.1	4.6 ± 2.4*	8.0 ± 6.3	9.2 ± 5.9	12.7 ± 9.2	14.2 ± 8.7*	15.4 ± 11.6	17.9 ± 10.6*
% BF^a	18.8 ± 5.3	22.8 ± 6.0*	22.6 ± 9.3	27.7 ± 8.8*	26.4 ± 10.9	30.5 ± 9.9*	23.4 ± 12.6	29.3 ± 9.9*
MVPA (minutes · day^-1)^b	31.5 ± 15.9*	24.5 ± 13.1^c	38.6 ± 21.2*	25.9 ± 15.5^d	42.0 ± 22.1*	22.7 ± 13.9	31.6 ± 18.1*	19.5 ± 13.1^e
TV (≥ 2 hr · day^-1)^f (%)	58	56	50	51	63	50	64^†	52
VG (≥ 1 hr · day^-1)^f (%)	22^†	12	42^†	14	60^†	32	66^†	34

Values are presented as mean ± SD.
SD, standard deviation.
^a Percentage of body fat determined by DXA scan.
^b moderate-to-vigorous physical activity.
^c n = 228.
^d n = 221
^e n = 187.
Response categories: (1) < 1 hr · day-1 or not at all; (2) ≥ 1 hr · day-1 but < 2 hr · day-1; (3) ≥ 2 hr · day-1 but < 3 hr · day-1;
(4) ≥ 3 hr · day-1 but < 4 hr · day-1; and (5) ≥ 4 hr · day-1.
* Age-specific comparison of boys and girls using Student's t-test (p < 0.05).
^† Age-specific comparison of boys and girls using the Cochran-Armitage trend test (p < 0.05).

ISSN: 1479-5868