We’re used to the idea that some aspects of our lives might put us at higher risk for certain diseases. We know, for example, that our diet and exercise habits may make us susceptible to some health problems. But in the case of multiple sclerosis, the place we live could raise our chances of developing the disorder and increase the risk of more severe symptoms.

Multiple Sclerosis and Latitude

Researchers have noted that multiple sclerosis (MS) seems more prevalent in the higher latitudes in the northern hemisphere and the lower latitudes in the southern hemisphere. In the past decade, research has confirmed that people living at higher latitudes in both hemispheres are at a statistically significant increased risk for the disorder.

Recent research suggests it’s not just the frequency of MS that increases the farther you go from the Equator. For example, a 2016 study found that the average age of MS onset for people living at latitudes above 50 degrees was two years younger than for those living below 19 degrees. In addition, a study published this year in the journal Neurology found that people living above 40 degrees latitude were likely to experience more severe MS and a faster decline in neurological function than those living at lower latitudes.

The latter study could cause concern since its 40-degree boundary is a relatively low latitude. In the United States, much of the population, including residents of New York, Boston, Chicago, Minneapolis, Portland, and Seattle, reside above that line.

Sunlight and Vitamin D

The link between latitude and MS is definite, but what’s behind it? The genetics of local populations and cultural differences might play a role, but a common factor among high-latitude residents is exposure to sunlight. At high latitudes, low sun angles, and short days during the winter limit the time locals are subject to exposure to the sun’s rays, which is a problem.

Sunlight, particularly its ultraviolet rays, is a vital source of nutrients essential to our health. For example, our bodies can create vitamin D3 when our skin absorbs ultraviolet B radiation, a component of sunlight. Without sunlight or some other source of vitamin D, we’re at risk of a vitamin D deficiency. That deficiency could lead to disorders ranging from osteoporosis to cancer and heart disease.

vitamin d multiple sclerosis

Scientists suspect a lack of vitamin D might also increase our risk of MS. Apart from the question of sunlight exposure, multiple studies have shown that people with higher vitamin D levels have a lower risk of developing MS. In addition, some studies have suggested that people with more vitamin D in their bloodstream may have less severe symptoms if they do develop the disorder.

Despite evidence of the connection, scientists still can’t state with certainty that higher vitamin D levels reduce the risk of MS, or that getting more of the vitamin through supplements does anything to prevent MS or improve its symptoms. Research into these possibilities is ongoing.

In the meantime, most doctors recommend that you try to get enough vitamin D from natural sources:

  • Get outside on sunny days (in moderation, because exposure to ultraviolet radiation poses risks, too), but if you live in the northern US or nearly anywhere in Europe, that’s not enough.
  • Vitamin D is in some food sources, including fatty fish and egg yolks, and some artificially fortified foods with the vitamin.
  • Vitamin D supplements may benefit people who can’t get enough of the nutrient from the sun or food sources. However, too much vitamin D can be toxic, so doctors recommend that most people between 1 and 70 take no more than 1000-2000 international units (IU) per day.

To learn more about our mission to find a cure for brain disorders worldwide, please visit our website at  The United Brain Association. Also, sign up for our email newsletter if you’d like to receive updates, news, scheduled events, or more information about our ongoing donor-funded research projects. Together we can find a cure for brain and mental health-related issues and disorders.

Share This Article

You Are Not Alone

For you or a loved one to be diagnosed with a brain or mental health-related illness or disorder is overwhelming, and leads to a quest for support and answers to important questions. UBA has built a safe, caring and compassionate community for you to share your journey, connect with others in similar situations, learn about breakthroughs, and to simply find comfort.

United Brain Association

Make a Donation, Make a Difference

We have a close relationship with researchers working on an array of brain and mental health-related issues and disorders.  We keep abreast with cutting-edge research projects and fund those with the greatest insight and promise.  Please donate generously today; help make a difference for your loved ones, now and in their future.                                                                 

The United Brain Association – No Mind Left Behind

Share Your Story

If you have an experience, a story, or someone in your life you want to recognize for their strength and willpower, please share it with us. We want to hear from you because listening is part of healing.

Connect With Us

Receive news on Brain Awareness, the Latest Research, and Personal Stories