Table 1

Descriptive characteristics of the study population
Whole sample (n= 825) Boys (n= 359) Girls (n= 466) p-gender difference
Age (y) 15.0 ± 0.301 15.0 ± 0.31 15.0 ± 0.29 0.87
Pubertal status (n (%))2,3
   Pre-pubertal 79 (9.8) 71 (20.7) 8 (1.7)
   Pubertal 730 (90.2) 272 (79.3) 458 (98.3) <0.001
Ethnicity (n (%))4
   White 767 (94.6) 341 (95.8) 426 (93.6)
   Other 44 (5.4) 15 (4.2) 29 (6.4) 0.18
Area-level SES (n (%))
   Low 124 (15.0) 62 (17.3) 62 (13.3)
   Middle 193 (23.4) 80 (22.3) 113 (24.3)
   High 508 (61.6) 217 (60.5) 291 (62.5) 0.27
Height (cm) 166.5 ± 7.9 171.4 ± 7.7 162.8 ± 5.8 <0.001
Weight (kg) 55.7 (13.3)5 57.8 (13.6) 53.9 (12.3) <0.001
BMI (kg/m2) 20.1 (3.9) 19.7 (3.5) 20.3 (4.1) 0.0011
Fat mass (kg) 11.5 (7.8) 8.2 (5.3) 13.7 (6.9) <0.001
Fat mass index (kg/m2) 4.2 (3.0) 2.8 (1.8) 5.2 (2.5) <0.001
Overfat (%)6 123 (14.9) 53 (14.8) 70 (15.0) 0.92
Sleep duration (min/d) 493.7 ± 52.8 487.9 ± 48.8 498.2 ± 55.4 <0.01

1Mean ± SD (all such values) and gender comparisons performed by independent sample t-tests; 2Due to missing data based on 809 participants (343 boys and 466 girls); 3For categorical variables gender comparisons were made by chi-square tests; 4Due to missing data based on 811 participants (356 boys and 455 girls); 5Median and IQR in parentheses (all such values) and gender comparisons performed by Wilcoxon-Mann–Whitney tests; 6 ≥85th percentile of age- and gender-specific fat mass index.

Collings et al.

Collings et al. International Journal of Behavioral Nutrition and Physical Activity 2014 11:23   doi:10.1186/1479-5868-11-23

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