For women, not having enough vitamin D not only increases their risk for osteoporosis, but also the risk for developing multiple sclerosis in later life, according to a new study.
Multiple sclerosis (MS) is described as a demyelinating disease whereby the body’s immune system mistakenly attacks the myelin sheath covers in the brain and spinal cord. This disrupts the electrical signal traveling from the brain to the body, and leads to physical and neurologic disabilities. The progressive form of MS causes patients to slowly deteriorate over time, while the relapsing form causes patients to go through bouts of symptoms and recovery. There is no cure for either form of MS.
Several studies have implicated vitamin D (chemically known as 25-hydroxyvitamin D) in multiple sclerosis with weak findings in small-scale studies.
"There have only been a few small studies suggesting that levels of vitamin D in the blood can predict risk,” explained Dr. Kassandra Munger, a professor at the Harvard T.H. Chan School of Public Health in Boston, MA.
To better describe this link, Dr. Munger and colleagues studied data from over 800,000 women in Finland. The samples were collected as part of prenatal blood testing, which the researchers used to examine levels of vitamin D and correlate to MS risks. Normal levels of vitamin D are typically 50 nanomoles per liter and above.
The team found 1,092 women were diagnosed with MS an average of nine years after sample collection. The vitamin D samples in these women were compared to 2,123 age-matched healthy study participants.
The comparison showed that women who had vitamin D deficiency, defined as levels lower than 30 nanomoles per liter, had a 43 percent increased risk of developing MS, as compared to those with normal vitamin D levels.
Women with the deficiency were also 27 percent more likely to develop MS than those with an insufficient level of vitamin D (defined as having levels between 30-49 nanomoles per liter).
“Our study, involving a large number of women, suggests that correcting vitamin D deficiency in young and middle-age women may reduce their future risk of MS,” said Dr. Munger.
But there’s a potential solution. The researchers found that by for every increase of 50 nanomolesper liter of vitamin D, the risk for MS decreases by 39 percent.
Of note, there’s only one approved drug for the treatment of primary progressive MS. The drug is known on the market as Ocrevus (ocrelizumab), and it works by weakening the immune system. In particular, IV infusions of Ocrevus prevent the B cells from attacking the protective myelin covers. Tested in patients with both forms of MS (the progressive form and the relapsing remitting form), Ocrevus seems to stop the inflammation process in the brain. This results in less fatigue and muscle weakness. Vision seems to also be improved. Furthermore, scans show significantly less brain loss with the help of ocrelizumab.
But if vitamin D is to be added to the short list of drugs for MS, researchers will need to show a stronger cause-and-effect relationship. “More research is needed on the optimal dose of vitamin D for reducing risk of MS," explains Dr. Munger. "But striving to achieve vitamin D sufficiency over the course of a person's life will likely have multiple health benefits."