Vitamin D, pregnancy, breastfeeding, and postpartum multiple sclerosis relapses.
OBJECTIVE
To determine whether low levels of 25-hydroxyvitamin D (25[OH]D) contribute to the increased risk of postpartum multiple sclerosis (MS) relapses.


METHODS
Prospective cohort study.


METHODS
Outpatients identified through membership records of Kaiser Permanente Northern California or Stanford University outpatient neurology clinics.


METHODS
Twenty-eight pregnant women with MS.


METHODS
We prospectively followed up patients through the postpartum year and assessed exposures and symptoms through structured interviews. Total serum 25(OH)D levels were measured using the DiaSorin Liaison Assay during the third trimester and 2, 4, and 6 months after giving birth. The data were analyzed using longitudinal multivariable methods.


METHODS
Levels of 25(OH)D and relapse rate.


RESULTS
Fourteen (50%) women breastfed exclusively, and 12 women (43%) relapsed within 6 months after giving birth. During pregnancy, the average 25(OH)D levels were 25.4 ng/mL (range, 13.7-42.6) and were affected only by season (P=.009). In contrast, in the postpartum period, 25(OH)D levels were significantly affected by breastfeeding and relapse status. Levels of 25(OH)D remained low in the exclusive breastfeeding group, yet rose significantly in the nonexclusive breastfeeding group regardless of season (P=.007, unadjusted; P=.02, adjusted for season). By 4 and 6 months after childbirth, 25(OH)D levels were, on average, 5 ng/mL lower in the women who breastfed exclusively compared with the nonbreastfeeding group (P=.001).


CONCLUSIONS
Pregnancy and exclusive breastfeeding are strongly associated with low 25(OH)D levels in women with MS. However, these lower vitamin D levels were not associated with an increased risk of postpartum MS relapses. These data suggest that low vitamin D in isolation is not an important risk factor for postpartum MS relapses.
Department of Research and Evaluation, Kaiser Permanente Southern California, 100 S. Los Robles, 2nd Floor, Pasadena, CA 91101, USA. annette.m.langer-gould@kp.org
Annette
A
Langer-Gould
Stella
S
Huang
Stephen K
SK
Van Den Eeden
Rohit
R
Gupta
Amethyst D
AD
Leimpeter
Kathleen B
KB
Albers
Ron
R
Horst
Bruce
B
Hollis
Lawrence
L
Steinman
Lorene M
LM
Nelson
D000328:Adult; D001942:Breast Feeding; D015331:Cohort Studies; D019587:Dietary Supplements; D005260:Female; D006801:Humans; D006887:Hydroxycholecalciferols / Q000097:blood; D008137:Longitudinal Studies; D009103:Multiple Sclerosis / Q000150:complications*; D049590:Postpartum Period; D011247:Pregnancy; D039401:Prenatal Nutritional Physiological Phenomena; D011446:Prospective Studies; D012008:Recurrence; D012621:Seasons; D014807:Vitamin D / Q000627:therapeutic use; D014808:Vitamin D Deficiency / Q000150:complications*; D014815:Vitamins / Q000627:therapeutic use
D006887:Hydroxycholecalciferols; D014815:Vitamins; D014807:Vitamin D