Seasonal variation in objectively measured physical activity, sedentary time, cardio-respiratory fitness and sleep duration among 8–11 year-old Danish children: a repeated-measures study

Table 1 Descriptive characteristics of the study population by gender

Variable	Boys (n = 376)	Girls (n = 354)	All (n = 730)
Age (years)	10.0 ± 0.6	9.9 ± 0.6 *	10.0 ± 0.6
3rd grade/4th grade	49% / 51%	49% / 51%	49% / 51%
Pubertal status (% 1/2/≥3)	76.5 / 19.4 / 4.2	54.5 / 36.2 / 9.3 **	65.7 / 27.6 / 6.7
Parents born in Denmark (% 0 / 1 / 2)	11.2 / 12.5 / 76.3	10.5 / 11.9 / 77.7	10.8 / 12.2 / 77.0
Highest education of household (%)¹	4.5 / 31.7 / 40.5 / 23.2	5.9 / 30.9 / 40.5 / 22.7	5.2 / 31.3 / 40.5 / 22.9
Weight (kg)	35.5 ± 7.2	34.5 ± 6.7	35.0 ± 7.0
Height (cm)	142.6 ± 7.1	142.1 ± 7.0	142.4 ± 7.1
Body mass index Z-score²	0.23 ± 1.12	0.04 ± 1.03 *	0.13 ± 1.08
Weight status (% uw/nw/ow/ob)³	8.3/77.8/11.5/2.4	12.3/75.1/11.4/1.1	10.2/76.5/11.5/1.8

Data are presented as mean ± standard deviation or proportions (%) and gender differences were tested using a two-sample t-test or Pearson’s chi-squared test. *, P < 0.05; **, P < 0.001.
¹Highest education of household: ≤10 years / 11–12 years / 13–16 years / ≥17 years.
²Based on World Health Organization Growth Reference data from 2007 [20].
³Based on age- and gender-specific cut-offs defined to pass through body mass index at 18.5, 25 and 30 kg/m² at age 18 years [21, 22]; uw/nw/ow/ob, underweight/normal weight/overweight/obese.

ISSN: 1471-2458