Table 2.

Prevalence of sleep disturbance according to gender and Young Diagnostic Questionnaire score

Gender	YDQ score	n	Sleep disturbance
			%	95% CI
Boys
	≤ 2	1776	38.6	36.3–40.9
	3–4	610	57.7	53.8–61.6
	≥ 5	249	70.3	64.6–76.0
Girls
	≤ 2	1501	44.5	42.0–47.0
	3–4	739	63.9	60.4–67.4
	≥ 5	389	78.4	74.3–82.5

Abbreviations: CI confidence interval, YDQ Young Diagnostic Questionnaire

The YDQ scores are interpreted as follows: ≤ 2, no Internet addiction; 3–4, at risk of Internet addiction; ≥ 5, Internet addiction