Exposure to pesticides could increase the risk of developing Parkinson's disease, researchers have warned.
Parkinson's can lead to difficulty in moving arms and legs
The European study, featured in New Scientist magazine, led by a University of Aberdeen expert, said gardeners should wear protective clothing.
But they accepted there were more significant Parkinson's risk factors.
A family history of the disease increases the risk, as does being knocked unconscious on repeated occasions, the researchers said.
Parkinson's Disease is an incurable degenerative neurological condition.
People with the condition have increasing difficulty in moving their limbs and develop tremors and facial tics.
Previous research has suggested that pesticides, which can be inhaled or absorbed through the skin, can affect the way the mitochondria, the "power house" of a cell, works.
The Geoparkinson study looked at almost 3,000 people in Scotland, Italy, Sweden, Romania and Sweden, including 767 with Parkinson's.
Those interviewed had an average age of 62.
They were all asked about their professional and leisure activities, and whether or not they had regularly used pesticides.
It was found that people with Parkinson's disease were more likely to have used pesticides regularly during their lives.
People classed as "low level" users, such as amateur gardeners, were 9% more likely than non-users to develop the disease.
High level users, such as farmers, were 43% more likely to do so.
Dr Finlay Dick, of the University of Aberdeen who worked on the study, said it was true other factors were linked to a higher increased risk of developing Parkinson's
He said: "There is a moderate increased risk linked to exposure to pesticides. I wouldn't want to over-emphasise the significance of the effect.
"But it's important that there are things people can do to reduce that risk - you can't change your parents."
Dr Dick said the study did not look at specific pesticides because people were unable to remember which they had used.
Dr Anthony Seaton, of the University of Aberdeen, who led the research, told New Scientist: "It considerably strengthens the case for pesticides being relevant to occupational risk of Parkinson's disease.
But David Coggon of the University of Southampton, who is also chairman of the Advisory Committee on Pesticides, said the study did not identify which pesticides were linked to an increased risk of Parkinson's.
"It's possible that just one or two are causing it, but slipped through the regulatory net."
He said he would like to see research looking at exposure to individual pesticides, and how they are used, to gain detailed data, rather than relying on people's memories about their pesticide use.
Robert Meadowcroft, of the Parkinson's Disease Society, said the link between Parkinson's and pesticides had been recognised for some time.
He added: "The causes of Parkinson┐s are still not clearly identified in the vast majority of cases.
"This research shows some evidence that head injury, pesticide exposure and family history of the disease are all risk factors in the development of Parkinson's."
A spokeswoman for the Department of the Environment, Food and Rural Affairs said the government's Advisory Committee on Pesticides had considered the evidence of a link between pesticide exposure and Parkinson's disease last year.
Its Medical and Toxicology Panel identified a "correlation between individuals' memory of exposure to pesticides and Parkinson's disease", but it did not establish a "specific link" between exposure and the development of this illness.