Living in a warmer climate from a younger age could lower the risk of getting multiple sclerosis (MS), according to Professor Luke O’Neill. 

MS is an autoimmune disease that causes nerve damage, muscle weakness, pins and needles and other symptoms. 

Prof O’Neill told Show Me the Science there remains much mysterious around what causes the disease, but new research is showing fascinating correlations. 

“MS turns out to be more common in the northern hemisphere,” he said. “Less sunlight and vitamin D could be part of it. 

“The latest discovery might explain this northern hemisphere - if people emigrate and they leave the northern hemisphere before the age of 15, they have a lower incidence of MS. 

“If they leave after 15, they have the incidence [probability] of where they came from in the northern hemisphere. 

“Something environmental must be happening.” 

Virus sources

This research gave rise to further revelations on the causes of MS, including the correlation between MS and the Epstein-Barr virus. 

“That virus makes a protein called EBNA1... with Epstein-Barr virus, your immune system is slightly different,” Prof O’Neill explained. 

“The virus begins to make its proteins and you begin to get those into the immune system and one of them looks a bit like a problem.” 

The interaction between EBNA1 and myelin, an insulating substance in the body, causing inflammation and other symptoms of MS. 

Multiple sclerosis and genetics

As is the case with many diseases, MS has also been shown to have some potential genetic origins. 

“It runs in families basically,” Prof O’Neill said. “If you’re identical twins and one twin gets it, there’s a 30% chance of the other twin developing MS. 

“Remember identical twins have the exact same gene, broadly speaking... if you're a sibling and there's a brother or sister, there's only a 2.5% chance.” 

The two genes connected to MS, HLADR15 and HLAC554, are important immune genes that contain 60% of the possible risk of MS.