Objective: To investigate the relationship between dietary supplementation of cod liver oil and the intensity of pain in people with musculoskeletal pain.
Design: Cross-sectional study.
Setting: Data from the Norwegian Health Survey 1985.
Subjects: All adult respondents who had reported musculoskeletal pain (n = 4490).
Main outcome measures: Intensity of musculoskeletal pain as assessed by self reports during an interview.
Results: In logistic regression analyses (adjusting for age, gender, socioeconomic status, civil status, smoking habits, physical exercise, mental distress, and use of medicines), there was a negative association between regular intake of cod liver oil during the previous week and intense pain (OR = 0.75; 95% CI: 0.56-1.00; P = 0.048) and considerable/intense pain (OR = 0.81; 95% CI: 0.67-1.00; P = 0.045). The association was stronger in the 33% of the respondents who reported a musculoskeletal disease, as expressed by the relationship of cod liver oil to intense pain (OR = 0.64; 95% CI: 0.43-0.95; P = 0.028) and considerable/intense pain (OR = 0.74; 95% CI: 0.54-1.03; P = 0.076). The association varied between diagnostic groups, and was not seen in people who did not report a musculoskeletal disease.
Conclusion: The study suggests that people with musculoskeletal pain experience less pain if they take cod liver oil.