Table 4.

Rates and univariate odds ratios for non-traceability and refusal and for self-completion of Kidscreen questionnaire

	Non-traceability a			Refusal a			Child completion of KIDSCREEN
	%	OR	(95% CI)	%	OR	(95% CI)	%	OR	(95% CI)
Child characteristics
Gender
Male	13	1.0	-	23	1.0	-	59	1.0	-
Female	12	0.9	(0.6 to 1.3)	26	1.2	(0.9 to 1.5)	64	1.2	(0.9 to 1.6)
Age in years
7 and 8	7	1.0	-	27	1.0	-	57	1.0	-
9	13	1.9	(1.0 to 3.5)	19	0.6	(0.4 to 1.0)	66	1.5	(1.0 to 2.3)
10	12	1.7	(0.9 to 3.1)	19	0.6	(0.4 to 1.0)	56	1.0	(0.6 to 1.5)
11	13	1.9	(1.0 to 3.4)	26	1.0	(0.6 to 1.5)	66	1.5	(0.9 to 2.3)
12 and 13	17	2.5	(1.4 to 4.5)	30	1.2	(0.8 to 1.8)	61	1.2	(0.8 to 1.8)
Walking ability b
Walks unaided	14	1.0	-	29	1.0	-	80	1.0	-
Walks using aids	11	0.8	(0.5 to 1.3)	18	0.5	(0.4 to 0.8)	67	0.5	(0.3 to 0.8)
Unable to walk	11	0.8	(0.5 to 1.2)	21	0.6	(0.4 to 0.9)	28	0.09	(0.07 to 0.14)
Seizures b
No	12	1.0	-	25	1.0	-	74	1.0	-
Yes	12	1.1	(0.7 to 1.6)	25	1.0	(0.7 to 1.4)	29	0.1	(0.1 to 0.2)
Vision problems b
No	12	1.0	-	24	1.0	-	65	1.0	-
Yes	11	0.8	(0.5 to 1.5)	27	1.2	(0.8 to 1.8)	7	0.03	(0.01 to 0.1)
Hearing problems b
No	13	1.0	-	27	1.0	-	62	1.0	-
Yes	9	0.7	(0.2 to 2.2)	19	0.6	(0.3 to 1.6)	22	0.2	(0.06 to 0.5)
IQ
>70	-	-	-	-	-	-	94	1.0
50 to 70	-	-	-	-	-	-	65	0.1	(0.1 to 0.2)
<50	-	-	-	-	-	-	5	0.003	(0.002 to 0.007)
Centre characteristics
Method of approach
Direct	13	1.0	-	24	1.0		-	-	-
Indirect	12	0.9	(0.7 to 1.3)	25	1.1	(0.8 to 1.4)	-	-	-

a Excluding North West Germany, where children were not sampled from a population-based register

b For assessment of response, impairment at age 4–5 years was obtained from the register; for assessment of child completion, impairment was obtained from interview.