Contributions
Abstract: 199
Type: Oral
Abstract Category: Clinical aspects of MS - Epidemiology
Background: Adequate vitamin D nutrition in healthy individuals is associated with a decreased risk of developing multiple sclerosis (MS), but data from prospective studies are limited.
Objective: To determine in a nationwide population of women whether there is an inverse association between levels of 25-hydroxyvitamin D (25[OH]D) during pregnancy and their future MS risk.
Methods: The Finnish Maternity Cohort began in 1983 and has stored serum samples taken early in the pregnancies for routine prenatal screening of over 800,000 women. Through registry linkages, we identified 1,247 women with MS diagnosed between 1983 and 2009 who had at least one serum sample in the FMC collected prior to their date of MS diagnosis; 47% of cases had 2 or more samples available. Cases were matched to up to 3 controls (n=2,453) on date of birth (+/- 2 years). 25(OH)D was measured using a chemiluminescence assay. For women with more than one available sample, we used a seasonally-adjusted average of 25(OH)D. We used conditional logistic regression to estimate the relative risk and 95% confidence intervals.
Results: Serum samples were collected on average 13 years before MS diagnosis. Average 25(OH)D levels were 29.7 nmol/L in the women who developed MS and 31.1 nmol/L in the controls. 57% of the women later diagnosed with MS and 52% of control women were vitamin D deficient (25[OH]D < 30 nmol/L). A 50 nmol/L increase in 25(OH)D was associated with a 37% reduced risk of MS (RR=0.63, 95%CI: 0.47-0.86), p=0.003. Women with 25(OH)D levels < 30 nmol/L had a 23% higher risk of MS (95% CI: 5 to 44%, p=0.009), as compared to women with levels between 30 nmol/L and 50 nmol/L, and a 48% higher risk (95%CI: 8 to 100%), p=0.01 as compared to women with levels >50 nmol/L. Spline analyses did not suggest a deviation from linearity. Restricting the analysis to women with 2 or more samples (n=519 MS cases/838 controls), or to MS cases with medical record confirmation of MS (n=607) did not change these results.
Conclusions: The results of this large prospective study support the hypothesis that vitamin D deficiency, which is highly prevalent in this Nordic population, increases the risk of MS, and strengthen the rationale for broad public health interventions to improve vitamin D levels.
Disclosure:
K Munger: nothing to disclose
K Hongell: nothing to disclose
J Aivo: nothing to disclose
M Soilu-Hänninen: nothing to disclose
H-M Surcel: nothing to disclose
A Ascherio: reports grants from National Institutes of Health, National Multiple Sclerosis Society, Department of Defense, Michael J Fox Foundation, Accelerated Cure Project, and Chronic Fatigue Initiative, and honoraria for scientific presentations from Bayer, Almirall, and Serono.
Abstract: 199
Type: Oral
Abstract Category: Clinical aspects of MS - Epidemiology
Background: Adequate vitamin D nutrition in healthy individuals is associated with a decreased risk of developing multiple sclerosis (MS), but data from prospective studies are limited.
Objective: To determine in a nationwide population of women whether there is an inverse association between levels of 25-hydroxyvitamin D (25[OH]D) during pregnancy and their future MS risk.
Methods: The Finnish Maternity Cohort began in 1983 and has stored serum samples taken early in the pregnancies for routine prenatal screening of over 800,000 women. Through registry linkages, we identified 1,247 women with MS diagnosed between 1983 and 2009 who had at least one serum sample in the FMC collected prior to their date of MS diagnosis; 47% of cases had 2 or more samples available. Cases were matched to up to 3 controls (n=2,453) on date of birth (+/- 2 years). 25(OH)D was measured using a chemiluminescence assay. For women with more than one available sample, we used a seasonally-adjusted average of 25(OH)D. We used conditional logistic regression to estimate the relative risk and 95% confidence intervals.
Results: Serum samples were collected on average 13 years before MS diagnosis. Average 25(OH)D levels were 29.7 nmol/L in the women who developed MS and 31.1 nmol/L in the controls. 57% of the women later diagnosed with MS and 52% of control women were vitamin D deficient (25[OH]D < 30 nmol/L). A 50 nmol/L increase in 25(OH)D was associated with a 37% reduced risk of MS (RR=0.63, 95%CI: 0.47-0.86), p=0.003. Women with 25(OH)D levels < 30 nmol/L had a 23% higher risk of MS (95% CI: 5 to 44%, p=0.009), as compared to women with levels between 30 nmol/L and 50 nmol/L, and a 48% higher risk (95%CI: 8 to 100%), p=0.01 as compared to women with levels >50 nmol/L. Spline analyses did not suggest a deviation from linearity. Restricting the analysis to women with 2 or more samples (n=519 MS cases/838 controls), or to MS cases with medical record confirmation of MS (n=607) did not change these results.
Conclusions: The results of this large prospective study support the hypothesis that vitamin D deficiency, which is highly prevalent in this Nordic population, increases the risk of MS, and strengthen the rationale for broad public health interventions to improve vitamin D levels.
Disclosure:
K Munger: nothing to disclose
K Hongell: nothing to disclose
J Aivo: nothing to disclose
M Soilu-Hänninen: nothing to disclose
H-M Surcel: nothing to disclose
A Ascherio: reports grants from National Institutes of Health, National Multiple Sclerosis Society, Department of Defense, Michael J Fox Foundation, Accelerated Cure Project, and Chronic Fatigue Initiative, and honoraria for scientific presentations from Bayer, Almirall, and Serono.