Women with low levels of vitamin D have a 43 percent higher risk of developing multiple sclerosis.
More than 2.3million people around the world have MS, including around 100,000 people in Britain and more than 400,000 in the US.
People normally get diagnosed between the ages of 20 and 40, but it is difficult to identify the crippling condition until symptoms become apparent.
Now, a study by Harvard T.H. Chan School of Public Health says measuring vitamin D levels could denote one's risk - which shows maintaining a healthy amount of the 'sunshine vitamin' is key to preventing MS.
Examining levels of the 'sunshine vitamin' in the blood may help predict whether a person is at risk of developing the crippling condition which affects the central nervous system
Study author Doctor Kassandra Munger said: 'There have only been a few small studies suggesting that levels of vitamin D in the blood can predict risk.
'Our study, involving a large number of women, suggests that correcting vitamin D deficiency in young and middle-age women may reduce their