Response rates and selection problems, with emphasis on mental health variables and DNA sampling, in large population-based, cross-sectional and longitudinal studies of adolescents in Norway

Table 6 Association between baseline smoking habits and baseline self-reported health, mental distress and externalized symptoms among participants in 2004 and all invitees

	Participants 2004							All invitees
Gender/ethnicity¹	Smoking 2001							Smoking 2001
Health variables collected	yes		no		Prevalence ratio			yes		no		Prevalence ratio
in 2001	n	%	n	%	PR	95% CI		n	%	n	%	PR	95% CI
Norway/western
Boys
Bad/not so good self-reported health	37	13.2	51	5.5	2.4	1.6	3.5	111	16.4	113	6.7	2.4	1.9	3.1
Mental distress - HSCL above cut off	30	10.6	48	5.2	2.1	1.3	3.2	100	14.8	107	6.3	2.3	1.8	3.0
Externalized symptoms	52	18.4	65	7.0	2.6	1.9	3.7	169	24.8	154	9.1	2.7	2.2	3.3
Girls
Bad/not so good self-reported health	100	19.9	108	10.2	2.0	1.5	2.5	178	21.0	163	11.0	1.9	1.6	2.3
Mental distress - HSCL above cut off	167	33.1	193	17.9	1.9	1.6	2.2	287	33.6	278	18.6	1.8	1.6	2.1
Externalized symptoms	84	16.6	44	4.1	4.1	2.9	5.8	180	21.1	76	5.1	4.2	3.2	5.4
Non western
Boys
Bad/not so good self-reported health	5	14.7	12	7.4	2.0	0.8	5.3	20	19.8	28	8.2	2.4	1.4	4.1
Mental distress - HSCL above cut off	8	24.2	16	9.9	2.5	1.1	5.3	15	15.3	34	10.1	1.5	0.9	2.7
Externalized symptoms	6	17.6	18	11.1	1.6	0.7	3.7	26	26.3	36	10.8	2.4	1.5	3.8
Girls
Bad/not so good self-reported health	11	26.2	35	16.0	1.6	0.9	3.0	20	28.2	56	15.6	1.8	1.2	2.8
Mental distress - HSCL above cut off	17	39.5	70	32.0	1.2	0.8	1.9	33	45.8	96	27.3	1.7	1.2	2.3
Externalized symptoms	13	30.2	14	6.3	4.8	2.4	9.4	23	31.9	21	5.9	5.4	3.2	9.3

Percentage with health symptoms and prevalence ratios (PRs) among smokers and non-smokers.
¹ Based on self-reported native country of mother and father.

ISSN: 1471-2458