Temporal trends and recent correlates in sedentary behaviours in Chinese children

Table 1 Characteristics of the study population from 1997 to 2006: China Health and Nutrition Surveys

	Survey year
	1997	2000	2004	2006
n	2469	1838	1382	1128
Age (yrs, mean ± SD)**	11.7 ± 3.1	12.0 ± 2.9	12.0 ± 3.2	11.7 ± 3.2
Male (%)	52.5	54.0	52.6	53.1
Urban (%)	29.6	29.4	29.4	28.9
Per capita family annual income (RMB ^§ , mean ± SD) ^†
Urban**	4389 ± 3090	5806 ± 4957	6980 ± 6368	8453 ± 8570
Rural***	3178 ± 2605	3728 ± 3042	4799 ± 4781	5187 ± 7820
Prevalence of screen time ≥ 2 hrs/d (%, Urban)
Boys aged 6-12 yrs*	13.3	16.4	31.7	36.7
Boys aged 13-18 yrs***	11.2	11.1	42.9	44.3
Girls aged 6-12 yrs***	13.5	11.3	33.7	27.2
Girls aged 13-18 yrs***	9.7	8.5	25.3	34.7
Prevalence of screen time ≥ 2 hrs/d (%, Rural)
Boys aged 6-12 yrs***	9.4	11.5	30.3	46.7
Boys aged 13-18 yrs***	5.7	7.6	22.9	32.5
Girls aged 6-12 yrs***	10.2	11.6	28.4	42.3
Girls aged 13-18 yrs***	3.0	8.3	16.7	24.6

*P < 0.01. **P < 0.001. ***P < 0.0001.
^§ RMB denotes Chinese currency.
^†The per capita family annual income in each survey year was inflated to values in 2009 by adjusting for consumer price index.

ISSN: 1479-5868