London, Jul 4 (IANS): Exposure to paint, varnish and other solvents may put people at a 50 per cent higher risk of developing multiple sclerosis (MS), a potentially disabling disease affecting the central nervous system, a study says.

With exposure to solvents, people who also carry genes that make them more susceptible to developing multiple sclerosis are nearly seven times as likely to develop the disease as compared to those with no solvent exposure who do not carry the MS genes, said the study published in the journal Neurology.

For people who have been smokers, the risk is even greater. Those who have been smokers with solvent exposure and the MS genes are 30 times more likely to develop MS than those who have never smoked or been exposed to solvents and who do not have the genetic risk factors, said the study.

"These are significant interactions where the factors have a much greater effect in combination than they do on their own," said study author Anna Hedstrom from the Karolinska Institutet in Stockholm, Sweden.

"It's possible that exposure to solvents and smoking may both involve lung inflammation and irritation that leads to an immune reaction in the lungs," Hedstrom added.

For the study, the researchers identified 2,042 people who had recently been diagnosed with MS and matched them with 2,947 people of the same age and sex.

Blood tests were used to determine whether the participants had two human leukocyte antigen gene variants -- one of which makes people more likely to develop MS and the other reduces the risk.

They were also asked whether they had been exposed to organic solvents, painting products or varnish and whether they had ever been a smoker.

The analysis showed that, MS genes and exposure to solvents combined were responsible for an estimated 60 per cent of the risk of developing MS.

The researchers determined that the MS genes and exposure to solvents combined were responsible for an estimated 60 percent of the risk of developing MS.