People with lighter coloured hair are more likely to develop Parkinson's as they get older, new research shows.
Scientists from Harvard University asked 131,821 participants to choose their hair colour from black, brown, blonde and red, with red being the lightest.
During the following 16-22 years, 539 people in this group were diagnosed with Parkinson's , with those with black hair least likely to develop the condition and participants with red most likely.
However, researchers emphasised that the difference was quite small.
Dr Kieran Breen, director of research and development at Parkinson's UK, commented: "Having lighter-coloured hair does not mean a person will go on to get Parkinson's.
"But this fascinating relationship may mean that changes in the genes that govern hair colour and pigmentation also play an important part in Parkinson's."
This comes after a study, published in the Journal of Neurology, Neurosurgery and Psychiatry found that common non-motor Parkinson's symptoms could mean that some with Parkinson's cannot drive safely.