The association of use of cod liver oil and multivitamin supplements with cumulative incidence of asthma over the 11-year follow-up period of the Nord-Trøndelag Health Study from 1995–1997 to 2006–2008 (N=16 952)
| Regular use of cod liver oil and multivitamin supplements in the previous year | Subjects n | Cases n (%) | Crude OR (95% CI) | Adjusted OR (95% CI) | ||
| Model I# | Model II¶ | Model III+ | ||||
| Reference group§ | 13 742 | 389 (2.8) | 1.00 | 1.00 | 1.00 | 1.00 |
| Cod liver oil only | 1163 | 46 (4.0) | 1.41 (1.04–1.93) | 1.59 (1.16–2.19) | 1.59 (1.16–2.18) | 1.53 (1.11–2.11) |
| Multivitamin supplements only | 997 | 46 (4.6) | 1.66 (1.21–2.27) | 1.55 (1.12–2.13) | 1.54 (1.12–2.13) | 1.48 (1.07–2.05) |
| Use of both | 1050 | 48 (4.6) | 1.64 (1.21–2.23) | 1.73 (1.26–2.37) | 1.73 (1.26–2.36) | 1.65 (1.20–2.26) |
#: adjusted for age, sex, smoking (current, former, never and unknown), light physical activity, education, social benefit, economic difficulties, family history of asthma and body mass index; ¶: adjusted for alcohol consumption in addition to the covariates in model I; +: adjusted for Hospital Anxiety and Depression Scale (HADS) scores for anxiety and depression, and chronic disease at baseline, in addition to the covariates in model I (n=16 819 due to missing HADS scores); §: nonusers or those with daily intake of cod liver oil or multivitamin supplements for <3 months.