A world-first clinical trial beginning in Hobart today will assess if vitamin D can stall or prevent the development of multiple sclerosis (MS).

The cause of the condition is not known, but research shows those living further from the equator are at higher risk.

People who live in Tasmania are 10 times more likely to develop the condition than their counterparts in the Northern Territory.

It has long been suspected that vitamin D, or a lack of it, has a large part to play in the development of MS.

Menzies Research Institute professor Bruce Taylor says a placebo-controlled trial to begin at Royal Hobart Hospital today will hopefully give scientific proof to that hypothesis.

"We know that MS is not evenly distributed around the world," he said.

"The further you get away from the equator in a genetically susceptible population, the greater your risk of getting MS.

"That means about 90 per cent of your risk of getting MS can be due to your environment.

"Our science all points to this, that vitamin D, derived from solar radiation, may be one of the clues," Professor Taylor said.

MS is an inflammatory disease that affects the brain and spinal chord, but those with MS can have varying symptoms.

'Major step forward'

Professor Taylor says MS is one of the most difficult diseases to study.

"And that's why it's unfortunately been very badly studied in the past, because it has a huge what we call interpersonal and intrapersonal variation," he said.

"So one can have very bad MS for a period of time and then they can just stop having attacks.

"We spent a lot of time designing the study, which means that if there is a significant effect of MS, we will be able to pick this is up in this study.

"And this is unique - no-one else in the world is doing this.

"This is an Australian and New Zealand first and this is really a major scientific step forward for MS," Professor Taylor said.

MS Research Australia chief executive Jeremy Wright says the study will provide new hope to those battling MS.

"We know a lot about the circumstantial evidence that links vitamin D deficiency and MS and we want to take that fact and act on it and see if vitamin D at the earliest stage of MS can really affect the progress of the disease, slow it or stop it," he said.

Sharlene Brown, 40, is one Tasmanian who hopes that this study will make sense of how she developed the disease.

She has looked at her lifestyle to see if it may have contributed to MS.

"I'm a bit of a bookworm, I must say I spend a lot of time inside," she said.

"I often wonder whether if I'd spent more time out in the playground instead of the library, whether that would have made a difference."

But despite being in remission from MS for more than nine years, her future health remains uncertain.

She hopes the results of this study will prevent a similar outcome for people yet to develop the condition.

"If you can help prevent future generations suffering from this type of illness and it can be done as simply as monitoring your vitamin D levels, then that's really exciting I think for people who have it or for those people who think they might actually be in the early stages of it," she said.

"I think that's the exciting part of the study.

"It could be something so simple."