To analyze the relationship between sleep duration, screen viewing time, and the prevalence of overweight/obesity among primary school students in Xuzhou.

Using a cluster sampling method, a total of 3 228 students (including 1 679 boys and 1 549 girls with an average age of 10.78±0.69 years) from grade one to six from 10 primary schools in Xuzhou underwent interview using a self-designed questionnaire containing basic characteristics, sleep duration, and screen viewing time. Data on height and weight were also collected. The relationship between sleep duration, screen viewing time, and overweight/obesity was analyzed using a logistic regression analysis.

The prevalence rates of overweight among boys and girls were 16.56% and 11.94%, respectively (χ²=13.59, P<0.05). The prevalence rates of obesity among boys and girls were 14.47% and 10.07%, respectively (χ²=14.01, P<0.05). In total, 74.41% students reported a lack of sleep; the average sleeping time was (9.24±1.07) h. The average sleeping time among boys was (9.35±1.12) h and among girls was (9.13±1.03) h. The difference in sleep duration between boys and girls was significant (t=5.79, P<0.05). The differences in sleep duration and overweight/obesity were significant between both boys (χ²=18.62, P<0.05) and girls (χ²=21.14, P<0.05). Regarding screen viewing time, 17.29% of students spent more than 2 hours per day viewing a screen. The difference in screen viewing time between boys and girls was significant (Z=3.02, P=0.014). The proportion of children with screen viewing time of more than 2 h/d among overweight/obese and healthy weight male students was 29.50% (82/278) and 22.56% (316/1401), respectively, which was significantly different (χ²=6.18, P=0.01). However, there was no significant difference when examining the same groups among girls (12.98% (24/185; obese/overweight) vs. 9.97% (136/1364; healthy weight); χ²=1.59, P=0.21). After adjusting for parental obesity, eating sweets, and physical activity, logistic regression analysis showed that students who had a sleep duration less than 10 h/d had an odds ratio of 1.4 (95% CI: 1.15-1.71), the odds ratio for boys and girls was 1.56 (95% CI: 1.13-2.14) and 1.69 (95% CI: 1.15-2.46). The students who had a screen viewing time of more than 2 h/d had an odds ratio of 1.14 (95% CI: 1.05-1.80); the odds ratio for boys in this group was 1.18 (95% CI: 1.03-1.67).

Short sleep duration is a risk factor for being overweight/obese in both boys and girls. However, long screen viewing times were associated with being overweight/obese only in boys.

Overweight; Obesity; Sleep duration; Screen viewing time; Primary school students