Table 1

Descriptive characteristics of the studied adolescents (n=359)
Variables All (n=359) Boys (n=178) Girls (n=181)
Age (y) 14.8 ± 1.2 14.8 ± 1.2 14.8 ± 1.1

Sexual maturation

(I/II/III/IV/V) (%)

(0/2/6/13/79) (0/3/9/20/68) (0/1/4/6/89)*
Body mass (Kg) 58.3 ± 13.1 62.2 ± 15.3 54.6 ± 9.1*
Height (cm) 164.6 ± 10.9 168.5 ± 12.2 160.4 ± 7.2*
Whole body lean mass (Kg) 40.5 ± 8.5 45.6 ± 8.5 35.5 ± 4.7*
Whole body fat mass (Kg) 14.8 ± 6.1 13.3 ± 6.5 16.4 ± 5.3*
Whole body BMC a (g) 1999.34 ± 421.73 2127.21 ± 473.35 1873.61 ± 318.34*
Lumbar spine BMC a (g) 51.15 ± 12.84 52.13 ± 14.87 50.16 ± 10.38
Femoral neck BMC a (g) 4.24 ± 0.89 4.63 ± 0.97 3.85 ± 0.61*
MVPA b (minutes/day) 58.8 ± 24.1 65.7 ± 24.8 49.9 ± 20.4*
TV viewing (minutes/day) 107.1 (62.1-150) 107.1 (57.8-139.3) 107.1 (75–167.1)
Use of computer games (minutes/day) 23.6 (0–60.) 36.4 (12.8-77.1) 7.5 (0–36.4)*
Use of console games (minutes/day) 4.3 (0–36.4) 25.7 (4.3-57.8) 0 (0–4.3)*
Use of internet for non-study (minutes/day) 45 (15–92.1) 36.4 (10.7-75) 57.8 (23.6-107.1)*
Use of internet for study (minutes/day) 15 (9.1-36.4) 15 (0–32.1) 15 (10-7-45)*
Time of study (minutes/day) 90 (36.4-132.9) 75 (23.6-120) 90 (45–150)*
Total sedentary time (minutes/day) 331.1 (242.1-460.2) 327.9 (241.1-457.5) 340.7 (242.1-473.6)

ANOVA was performed for normally distributed variables (mean ± SD) and U Mann Whitney for non-normally distributed variables (median and interquartil intervals).

a Bone Mineral Content; b Moderate to Vigorous Physical Activity.

* Sex differences (p<0.05).

Gracia-Marco et al.

Gracia-Marco et al. BMC Public Health 2012 12:971   doi:10.1186/1471-2458-12-971

Open Data