Pharmacokinetics of Vitamin D in Multiple Sclerosis and in Health

Inclusion Criteria:

• Female
• Healthy or multiple sclerosis
• Aged 18 to 60
• Body mass index is between 18 kg/m2 and 30 kg/m2
• Screening 25-hydroxyvitamin D level ≤ 75 nmol/L (30 ng/mL)
• White race
• Non-Hispanic ethnicity
• Willing to use birth control during study
• Willing to not use tanning bed during study

If subject has multiple sclerosis:

• Relapsing-remitting MS, as defined by McDonald 2005 criteria
• Screening Expanded Disability Status Scale score ≤ 3.0
• Using no medication for MS, or taking Copaxone, (glatiramer acetate), interferons, or natalizumab

Exclusion Criteria:

• Pregnant or nursing
• Taking multivitamin & unwilling to remain off it during study
• Taking cod liver oil & unwilling to remain off it during study
• On a fat-restricted diet
• History of renal disease or nephrolithiasis (kidney stones)
• History of liver disease
• Taking thiazide diuretics
• History of hyperthyroidism
• History of infection with Mycobacterium species
• History of sarcoidosis
• History of cancer
• History of cardiac disease
• History of HIV
• History of gastrointestinal disorder
• Taking medications that interfere with gastrointestinal absorption
• Cigarette smoker in past month
• Use of illicit drugs in past month
• Use of steroids in past month
• History of hypercalcemia, and screening serum calcium ≤ 10 mg/dL (UCSF) or ≤ 10.7 mg/dL (Johns Hopkins)
• History of hypercalciuria
• Evidence of anemia (Hgb <11.0 g/dL)
• History of other serious medical conditions
• Taking medications that involve the P450 system or may interact with vitamin D (digoxin, diltiazem, verapamil, cimetidine, heparin, or low-molecular weight heparin)
• Other concerns about safety from the perspective of the treating physician

If subject has MS:

-History of major heat sensitivity (leading to sun-avoidant behaviors)