Table 1.

Examples of baseline socio-demographic and health characteristics of the KiGGS cohort (recruited from 2003–2006)^a

Age, years	0–2 (N = 2805)			3–6 (N = 3875)			7–10 (N = 4148)			11–13 (N = 3076)			14–17 (N = 3736)
	N	%b	% wt**	N	%b	% wt**	N	%b	% wt**	N	%b	% wt**	N	%b	% wt**
Demographics (according to registration office)
Non-German citizenship	133	4.7	5.4	316	8.2	9.3	415	10.0	11.5	276	9.0	9.5	339	9.1	8.9
Region of residence: Western Germany (excluding Berlin)	1839	65.6	82.4	2571	66.4	83.9	2796	67.4	86.4	2065	67.1	86.5	2470	66.1	78.1
Municipality size: <5000	611	21.8	16.9	866	22.4	17.6	873	21.1	18.0	664	21.6	18.1	792	21.2	19.3
5000 to <20 000	755	26.9	24.8	1024	26.4	26.0	1108	26.7	27.2	817	26.6	27.6	951	25.5	27.3
20 000 to <100 000	800	28.5	29.8	1139	29.4	29.8	1218	29.4	29.6	890	28.9	28.9	1119	30.0	29.4
100 000 or more	639	22.8	28.4	846	21.8	26.7	949	22.9	25.2	705	22.9	25.4	874	23.4	24.0
Demographics (information given by parents)
Child’s sex: Female	1389	49.5	48.7	1924	49.7	48.7	2021	48.7	48.7	1488	48.4	48.7	1832	49.0	48.7
Migration background:
One-sided	280	10.1	11.6	317	8.3	9.7	309	7.5	8.2	188	6.1	7.2	198	5.3	6.1
Two-sided	361	13.0	17.6	569	14.8	19.3	606	14.7	18.1	487	15.8	17.9	567	15.2	15.6
Missing	18			32			26			0			4
Education of familyc: Low	355	12.8	25.3	555	14.5	28.6	692	16.9	33.1	566	18.7	37.0	692	19.2	35.8
Middle	1616	58.3	49.4	2205	57.5	48.2	2281	55.6	46.0	1676	55.4	43.8	1940	53.9	44.5
High	803	29.0	25.2	1076	28.1	23.2	1131	27.6	20.9	785	25.9	19.2	969	26.9	19.7
Missing	31			39			44			49			135
Socio-economic status of family: Low	417	15.0	19.1	606	15.8	20.1	681	16.6	21.4	493	16.3	19.9	517	14.4	18.4
Middle	1656	59.7	57.9	2270	59.3	58.6	2444	59.6	59.1	1840	60.9	61.5	2191	61.2	62.5
High	699	25.2	23.0	955	24.9	21.3	976	23.8	19.5	688	22.8	18.7	873	24.4	19.1
Missing	33			44			47			55			155
Health status and behaviours
General health8: Very good/good	2698	97.0	97.1	3595	93.4	92.9	3888	94.4	93.9	2828	93.0	92.4	3296	91.0	90.4
Missing	22			25			31			35			114
Children with special health care needs: CSHCN9 Screening positive	128	5.0	4.7	405	11.7	11.4	645	17.0	17.0	503	17.4	16.1	545	15.9	15.4
Missing	220			399			344			241			299
Allergic rhinitis (hay fever): Lifetime diagnosis yes	39	1.5	1.6	226	6.2	6.5	442	11.4	11.7	460	16.1	15.4	680	20.0	20.0
Missing (refused/‘don’t know’)	123			241			271			225			330
Bronchial asthma: Lifetime diagnosis yes	15	0.5	0.5	91	2.4	2.9	192	4.7	4.8	215	7.1	6.6	261	7.1	7.0
Missing (refused/‘don’t know’)	40			60			54			42			51
Atopic dermatitis: Lifetime diagnosis yes	286	10.8	10.2	616	17.0	16.4	735	18.8	17.4	519	18.1	17.4	568	16.6	16.5
Missing (refused/‘don’t know’)	165			250			245			201			312
Attention deficit hyperactive disorder: Lifetime diagnosis	yes			91	2.5	2.7	287	7.5	7.8	255	9.0	9.1	237	6.9	7.9
Missing (refused/‘don’t know’)	2805 not measured			275			319			240			305
SDQ-measured mental health problems:10 Total score borderline or abnormal				691	18.2	19.4	854	21.0	22.5	627	20.8	21.5	557	15.5	16.7
Missing	2805 not measured			69			75			68			146
Current smoking: Yes										124	4.1	3.4	1170	31.7	33.2
Missing	2805 not measured			3875 not measured			4148 not measured			43			40
Obesityd: Yes	20	2.2	2.5	120	3.1	3.2	269	6.5	7.1	207	6.8	7.9	308	8.3	9.5
Missing	1890 (1860 children age <2 years excluded)			39			17			12			21

^a n = 17 640 because one study participant requested the retrospective deletion of all of their contact and survey data.

^bProportion in crude net sample (excluding missing values); wt** = weighted prevalence rates (to German minor population 31 12 2004).

^cEducation groups according to CASMIN (Comparative Analysis of Social Mobility in Industrial Nations).

^dBased on national German reference percentiles.¹¹