December 09, 2015
Multiple Sclerosis (Houndmills, Basingstoke, England)
TAKE-HOME MESSAGE
- The authors report on data from the Norwegian portion of the multinational questionnaire-based case–control study Environmental Factors in Multiple Sclerosis (EnvIMS) with regard to timing of cod liver oil use in MS patients vs controls. In Norway, there is essentially no vitamin D contribution from sun exposure during the winter, and thus cod liver oil is routinely recommended. The Norway component of this study included 953 MS patients (maximum disease duration of 10 years) and 1717 controls. In a mail questionnaire, they were asked if they used cod liver oil or capsules at six different age ranges, the frequency, and the amount. Also assessed were other sources of vitamin D. Respondents who reported cod liver oil use during adolescence (aged 13–18 years) had a decreased risk of MS (OR, 0.67), while use during childhood or adulthood was not associated with change in risk. Additionally, there was an inverse relationship between the dose during adolescence and the risk of MS, with the lowest risk associated with a dose of 600 to 800 IU of vitamin D3 per day.
- While these data would be subject to recall bias, the large doses of vitamin D commonly used and the low confounding from sun exposure make the results compelling.
– Sarah Matteson Kranick, MD
Abstract
BACKGROUND
Low vitamin D levels have been associated with an increased risk of multiple sclerosis (MS), although it remains unknown whether this relationship varies by age.
OBJECTIVE
The objective of this paper is to investigate the association between vitamin D3 supplementation through cod liver oil at different postnatal ages and MS risk.
METHODS
In the Norwegian component of the multinational case-control study Environmental Factors In Multiple Sclerosis (EnvIMS), a total of 953 MS patients with maximum disease duration of 10 years and 1717 controls reported their cod liver oil use from childhood to adulthood.
RESULTS
Self-reported supplement use at ages 13-18 was associated with a reduced risk of MS (OR 0.67, 95% CI 0.52-0.86), whereas supplementation during childhood was not found to alter MS risk (OR 1.01, 95% CI 0.81-1.26), each compared to non-use during the respective period. An inverse association was found between MS risk and the dose of cod liver oil during adolescence, suggesting a dose-response relationship (p trend = 0.001) with the strongest effect for an estimated vitamin D3 intake of 600-800 IU/d (OR 0.46, 95% CI 0.31-0.70).
CONCLUSIONS
These findings not only support the hypothesis relating to low vitamin D as a risk factor for MS, but further point to adolescence as an important susceptibility period for adult-onset MS.