Table 2.

Odds ratios (OR) and corresponding 95% confidence intervals (CI) for sleep difficulties including individual-related variables

Model 1 predictors	Odds ratio	Lower CI	Upper CI
Sex (malea):
female	1.71***	1.44	2.04
Age category (11 years olda):
13 years old	1.05	0.85	1.30
15 years old	0.96	0.76	1.20
Family structure (mother and father1):
only mother	1.19	0.92	1.53
only father	0.66	0.31	1.40
blended family	1.14	0.75	1.72
other	1.14	0.54	2.40
Siblings (only childa):
one sibling	1.37**	1.08	1.75
at least two siblings	1.31	0.99	1.71
Socio-economic status (lowa):
medium	0.89	0.72	1.09
high	0.90	0.71	1.14
Self-perceived ill health	1.49***	1.3	1.72
Alcohol use	1.16**	1.04	1.29
Smoking	1.12**	1.05	1.21
Screen time	1.06***	1.03	1.09
Physical activity	1.00	0.96	1.05

*p < 0.05; **p < 0.01; ***p < 0.001

^aReference category