Decline in physical activity during adolescence is not associated with changes in mental health

BMC Public Health

Table 1 Descriptive statistics of the study sample

	All (N = 158)		Cohort 7^th Graders (N = 98)		Cohort 9^th Graders (N = 60)
	Baseline	Follow-up	Baseline (Grade 7)	Follow-up (Grade 8)	Baseline (Grade 9)	Follow-up (Grade 10)
Age (years)	13.60 ± 1.13	14.62 ± 1.20*	12.79 ± 0.45	13.75 ± 0.42*	14.92 ± 0.47	16.04 ± 0.48*
Sex
Boys	61 (38.6 %)		38 (38.8 %)		23 (38.3 %)
Girls	97		60		37
Nationality
Native Dutch	140 (88.6 %)		88 (89.8 %)		52 (86.7 %)
Non-native Dutch	18		10		8
Educational level
SGSE	40 (25.3 %)		31 (31.6 %)		9 (15.0 %)
UPE	118		67		51
SES
Low/medium	34 (21.9 %)		21 (21.9 %)		13 (22.0 %)
High	121		75		46
Body mass index (kg/m2)	18.75 ± 2.82	19.45 ± 2.83*	17.88 ± 2.81	18.72 ± 2.89*	20.18 ± 2.21	20.65 ± 2.30*
Cardiovascular fitness (VO2max)	51.53 ± 5.51	51.02 ± 6.14*	51.81 ± 5.72	51.70 ± 6.19	51.06 ± 5.17	49.90 ± 5.94*
Total PA (Accelerometer steps)	69908 ± 18786	59229 ± 15021*	73672 ± 18208^B	58405 ± 13809*^B	63759 ± 18223^B	60573 ± 16851^B
Depressive symptoms	11.62 ± 9.20	10.21 ± 8.95*	10.99 ± 9.01	9.12 ± 8.03* ^B	12.65 ± 9.49	11.98 ± 10.10 ^B
Self-esteem	22.02 ± 5.34	22.65 ± 5.30	22.39 ± 5.27	23.49 ± 4.93*^B	21.42 ± 5.45	21.29 ± 5.62^B

SGSE senior general secondary education, UPE university preparatory education, Total PA total amount of physical activity per week measured objectively by accelerometer, VO2max maximum oxygen consumption
* significantly different from baseline at p < .05
^B indicates significant difference between 7^th graders and 9^th graders

ISSN: 1471-2458