Clinical implications of a possible role of vitamin D in multiple sclerosis

Hypovitaminosis D is currently one of the most studied environmental risk factors for multiple sclerosis (MS) and is potentially the most promising in terms of new clinical implications. These practical consequences, which could be applied to MS patients without further delay, constitute the main purpose of this review. Vitamin D is involved in a number of important general actions, which were not even suspected until quite recently. In particular, this vitamin could play an immunomodulatory role in the central nervous system. Many and varied arguments support a significant role for vitamin D in MS. In animal studies, vitamin D prevents and improves experimental autoimmune encephalomyelitis. Epidemiologically, latitude, past exposure to sun and the serum level of vitamin D influence the risk of MS, with, furthermore, significant links existing between these different factors. Clinically, most MS patients have low serum levels of vitamin D and are in a state of insufficiency or even deficiency compared to the international norm, which has been established on a metabolic basis. Large therapeutic trials using vitamin D are still lacking but the first results of phase I/II studies are promising. In the meantime, while awaiting the results of future therapeutic trials, it can no longer be ignored that many MS patients have a lack of vitamin D, which could be detected by a serum titration and corrected using an appropriate vitamin D supplementation in order to restore their serum level to within the normal range. From a purely medical point of view, vitamin D supplementation appears in this light to be unavoidable in order to improve the general state of these patients. Furthermore, it cannot currently be ruled out that this supplementation could also be neurologically beneficial

Predictors of vitamin D biochemical status in a large sample of middle-aged male smokers in Finland

OBJECTIVES: As vitamin D deficiency is considered to be more common in regions with little solar ultraviolet light in winter, the aim of the present study was to investigate predictors of vitamin D status by season within a large sample of male smokers from Finland, a country where there is negligible solar ultraviolet light in winter. METHODS: Vitamin D (measured by 25-hydroxyvitamin D (25(OH)D) nmol/L) and other serum constituents were assayed and measured anthropometry, and self-reported dietary intake and physical activity (PA) were obtained and analysed by step-wise multiple linear and logistic regression in 2,271 middle-aged Finnish male smokers. RESULTS: Twenty-seven % of the population in winter and 17% in summer had serum 25(OH)D levels < 25 nmol/L, respectively. In summer, in multiple logistic regression analyses with adjustment for confounding and other predictors, high dietary vitamin D (OR=3.6; 95% CI= 1.5–8.5), some leisure time PA (OR=2.0; 95% CI=1.3–3.1) and having a body mass index (BMI) ≥ 21 kg/m(2) compared to < 21 kg/m(2) (OR=2.6; 95% CI=1.3–5.0) were associated with 25(OH)D ≥ 25 nmol/L. In winter, additional modifiable factors were occupational PA (OR=1.6; 95% CI=1.1–2.5), and high fish (OR=3.1; 95% CI=1.7–6.2) or poultry consumption (OR=1.7; 95%CI=1.1–2.7). Predictors from linear regression analyses of continuous levels of 25(OH)D were similar to the logistic regression analyses of 25(OH)D < 25 nmol/L. CONCLUSION: In this Finnish sample more vitamin D intake, PA and having a BMI ≥ 21 may play important modifiable roles in maintaining an adequate vitamin D status