Vitamin D intake and incidence of multiple sclerosis.
BACKGROUND
A protective effect of vitamin D on risk of multiple sclerosis (MS) has been proposed, but no prospective studies have addressed this hypothesis.


METHODS
Dietary vitamin D intake was examined directly in relation to risk of MS in two large cohorts of women: the Nurses' Health Study (NHS; 92,253 women followed from 1980 to 2000) and Nurses' Health Study II (NHS II; 95,310 women followed from 1991 to 2001). Diet was assessed at baseline and updated every 4 years thereafter. During the follow-up, 173 cases of MS with onset of symptoms after baseline were confirmed.


RESULTS
The pooled age-adjusted relative risk (RR) comparing women in the highest quintile of total vitamin D intake at baseline with those in the lowest was 0.67 (95% CI = 0.40 to 1.12; p for trend = 0.03). Intake of vitamin D from supplements was also inversely associated with risk of MS; the RR comparing women with intake of >or=400 IU/day with women with no supplemental vitamin D intake was 0.59 (95% CI = 0.38 to 0.91; p for trend = 0.006). No association was found between vitamin D from food and MS incidence.


CONCLUSIONS
These results support a protective effect of vitamin D intake on risk of developing MS.
Munger
K L
KL
Department of Nutrition, Harvard School of Public Health, 665 Huntington Ave., Boston, MA 02115, USA. kgorham@hsph.harvard.edu
Zhang
S M
SM
O'Reilly
E
E
Hernán
M A
MA
Olek
M J
MJ
Willett
W C
WC
Ascherio
A
A
D000293:Adolescent; D000328:Adult; D004032:Diet; D019587:Dietary Supplements; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000453:epidemiology* / Q000517:prevention & control*; D009726:Nurses / Q000706:statistics & numerical data; D016017:Odds Ratio; D011446:Prospective Studies; D012306:Risk; D014481:United States / Q000453:epidemiology; D014807:Vitamin D / Q000008:administration & dosage / Q000494:pharmacology*
D014807:Vitamin D