Table 1

Baseline characteristics in association with cod liver oil intake, the HUNT study, 1995–1997 to 2006–2008 (n=17 528)

		Cod liver oil daily intake ≥1 month in past year
	No. of subjects	n	%	Crude OR (95% CI)
Total	17528	3076	17.5
Age at baseline (years)
19–29	2805	345	12.3	1.00 (reference)
30–39	5424	774	14.3	1.19 (1.04 to 1.36)
40–49	6701	1309	19.5	1.73 (1.52 to 1.97)
50–55	2598	648	24.9	2.37 (2.05 to 2.74)
Sex
Women	9786	1937	19.8	1.00 (reference)
Men	7742	1139	14.7	0.70 (0.65 to 0.76)
Daily smokers
No	11855	2195	18.5	1.00 (reference)
Yes	4761	702	14.7	0.76 (0.69 to 0.83)
Unknown	912
Physical activity (h/week)
<1	3810	549	14.4	1.00 (reference)
1–2	6420	1151	17.9	1.30 (1.16 to 1.45)
≥3	5569	1069	19.2	1.41 (1.26 to 1.58)
Unknown	1729
Education (years)
<10	3203	567	17.7	1.00 (reference)
10–12	9365	1416	15.1	0.83 (0.74 to 0.92)
≥13	4846	1074	22.2	1.32 (1.18 to 1.48)
Unknown	114
Social benefit
Non-recipient	13221	2222	16.8	1.00 (reference)
Recipient	3213	670	20.9	1.30 (1.18 to 1.44)
Unknown	1094
Economic difficulties
No	11863	2203	18.6	1.00 (reference)
Yes	5468	838	15.3	0.79 (0.73 to 0.87)
Unknown	197
Family history of asthma
No	13606	2365	17.4	1.00 (reference)
Yes	2926	535	18.3	1.06 (0.96 to 1.18)
Unknown	996
Body mass index (kg/m²)
<25.0	8289	1503	18.1	1.00 (reference)
25.0–29.9	7251	1271	17.5	0.96 (0.88 to 1.04)
≥30.0	1955	296	15.1	0.81 (0.70 to 0.92)
Unknown	33