Table 2.

Association of risk factors with HRQoL score based on mixed-effects linear regression analysis

Lifestyle-related behavior	Mean (SD)	Univariable modeld			Multivariable modele
		Mean difference	95% CI	P	Mean difference	95% CI	P
Physical activitya
Sufficient	0.82 (0.15)	Ref			Ref
Insufficient	0.77 (0.18)	− 0.04	− 0.07, − 0.01	< 0.001	− 0.03	− 0.04, − 0.01	< 0.001
Screen time
< 2 h/day	0.78 (0.17)	Ref			Ref
≥ 2 h/day	0.73 (0.19)	− 0.05	− 0.09, − 0.01	0.010	− 0.04	− 0.070, − 0.02	0.002
Sleeping timeb
Sufficient	0.84 (0.16)	Ref			Ref
Insufficient	0.77 (0.17)	− 0.10	− 0.15, − 0.05	< 0.001	− 0.06	− 0.07, − 0.04	< 0.001
Sugar-sweetened beverage consumptionc
No	0.79 (0.17)	Ref			Ref
Yes	0.76 (0.17)	− 0.02	− 0.05, 0.01	0.119	− 0.02	− 0.03, − 0.01	< 0.001
Fast food consumptionc
No	0.79 (0.17)	Ref			ref
Yes	0.76 (0.18)	− 0.03	− 0.06, 0.001	0.060	− 0.03	− 0.04, − 0.02	< 0.001

^aSufficient physical activity refers to at least 60 min/day moderate-vigorous intensity physical activity plus ≥ 3 days muscle/bone-strengthening; while insufficient physical activity means less than 60 min/day moderate-vigorous intensity physical activity or having no ≥ 3 days muscle/bone-strengthening

^bSleeping time: sufficient sleeping time was defined as 10 h/day for children aged 7–13, 9 h/day for children aged 13–16, and 8 h/day for those aged 16–19, based on guidelines for promotion of children and adolescents’ physical activity and fitness by The State Council of China

^cFF and SSB consumption was classified as “no” or “yes” based on the weekly consumption frequency, separately

^dModel 1: univariate mixed-effects model with school class as the random effect

^eModel 2: multivariate mixed-effects linear regression analysis with adjustment for age, gender, school type, residence, parental educational attainment, body weight status and class-level clustering effects