The association of screen time with childhood obesity and metabolic status: a mediation analysis of cardiorespiratory fitness.

Higher screen time was significantly associated with increased visceral fat area in children after adjusting for covariates.

• β = 0.029, P = 0.009
• Adjustments included sex, age, maternal education level, physical activity, and diet
• Generalized linear mixed models were employed for analysis
• Sample consisted of 1,286 third-grade students in Ningbo, China

Higher screen time was significantly associated with increased body fat mass index in children.

• β = 0.109, P = 0.017
• Body fat mass index (BFMI) was derived from body composition measurements
• Analysis adjusted for sex, age, maternal education level, physical activity, and diet

Higher screen time was significantly associated with increased body fat percentage in children.

• β = 0.469, P = 0.010
• Body fat percentage (BFP) was measured via body composition assessment
• Analysis adjusted for sex, age, maternal education level, physical activity, and diet

Higher screen time was significantly associated with decreased high-density lipoprotein cholesterol in children.

• β = -0.014, P = 0.038
• HDL-C was measured from fasting blood samples
• This was the only lipid/metabolic blood marker found to be significantly associated with screen time in the adjusted models

Cardiorespiratory fitness mediated a large proportion of the association between screen time and visceral fat area.

• CRF explained 66.6% of the association between screen time and VFA (P < 0.05)
• Mediation analysis was performed using bootstrap resampling
• CRF was assessed using the 20-meter shuttle run test

Cardiorespiratory fitness mediated a substantial proportion of the association between screen time and body fat mass index.

• CRF explained 67.5% of the association between screen time and BFMI (P = 0.014)
• Mediation analysis was performed using bootstrap resampling
• This represented the largest mediation proportion among the obesity-related indicators tested

Cardiorespiratory fitness mediated a substantial proportion of the association between screen time and body fat percentage.

• CRF explained 65.1% of the association between screen time and BFP (P = 0.006)
• Mediation analysis was performed using bootstrap resampling

Cardiorespiratory fitness mediated a smaller but significant proportion of the association between screen time and HDL-C.

• CRF explained 22.6% of the association between screen time and HDL-C (P = 0.026)
• This mediation proportion was notably smaller than that observed for adiposity-related outcomes (66.6%–67.5%)
• Mediation analysis was performed using bootstrap resampling

The study was conducted using baseline data from the OptiChild study involving third-grade students in Ningbo, China.

• Sample size was 1,286 third-grade students
• Anthropometric measurements, body composition, blood pressure, and fasting blood samples were collected
• Screen time, physical activity, and diet quality were assessed through questionnaires
• CRF was assessed using the 20-meter shuttle run test