Sunlight works against multiple sclerosis

Christiane Fux studied journalism and psychology in Hamburg. The experienced medical editor has been writing magazine articles, news and factual texts on all conceivable health topics since 2001. In addition to her work for, Christiane Fux is also active in prose. Her first crime novel was published in 2012, and she also writes, designs and publishes her own crime plays.

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UV radiation can apparently have a positive effect on the course of multiple sclerosis. Sunbathing seems to have a similar effect as the drug interferon. However, too much sunlight can also have negative effects.

Those who live far in the north or in the extreme south of the planet are more likely to develop multiple sclerosis (MS). This connection aroused the interest of science early on. Now it is clear: UV radiation actually has an effect on the likelihood of illness - but also on the course.

Multiple sclerosis is an inflammatory disease of the nervous system that usually runs in phases and, among other things, leads to paralysis.

The US epidemiologist Gil Beebe established the connection between MS and latitude as early as 1967. He had observed soldiers who were stationed with their families all over the world.

What role does UV radiation play?

But the exact influence of ultraviolet light on the disease remained unclear for a long time. Does the sun only affect the chances of getting MS in the first place? Or are individual people affected differently depending on where they live?

Scientists from the Competence Network MS (KKNMS) and the Collaborative Research Center Multiple Sclerosis (SFB TR128) have shown that UV light triggers very similar processes in the body of MS patients as the drug interferon.

"Sunlight apparently has a positive effect on the severity of MS," explains Prof. Nicholas Schwab from the Department of Neurology in Münster.

For their work, the scientists evaluated the data from around 2000 MS patients. On this basis, numerous influencing factors could be taken into account, including place of residence, gender and lifestyle, but also the genetic predisposition for sensitivity to the sun.

The north-south divide is already evident in Germany

The results of the study indicate that UV light and MS are already related to a relatively small area like Germany with a north-south extension of almost 1000 km. The active foci of inflammation in the brain and spinal cord and also the degree of impairment increase on average from southern to northern Germany. In return, the seasonally adjusted vitamin D level - as well as solar radiation - decreases towards the north.

What role does vitamin D play?

Researchers have long suspected that vitamin D affects the immune system and has anti-inflammatory effects, among other things. It has now been confirmed that the sun affects MS in other ways.

Information about this has now been provided by data from NASA. Estimates of the amount of UV light to which the subjects were exposed on average in the year before the examination show that if the sun exposure increases, the MS symptoms decrease on average.

However, if the patients were previously treated with interferon-beta, the sunlight no longer had any effect. One reason could be that interferon beta affects vitamin D production. The natural north-south divide in vitamin D levels could thus be eliminated

Too much sun also increases MS

Despite the potential benefits, the following also applies to MS patients: Excessive UV radiation can be harmful. Intensive sunbathing promotes the development of skin cancer, especially in fair-skinned people.

Too much sunlight can also adversely affect the course of the disease in MS patients. According to the recommendation of the World Health Organization, half an hour of sun a day makes sense for most people - especially if they suffer from multiple sclerosis.

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