The smell of fresh paint, newly polished shoes or nail polish remover all reach our noses as solvents in the products we use evaporate.

Love or hate these smells, research out this week links exposure to solvents to a significant increase in the risk of developing multiple sclerosis.

A progressive disease of the central nervous system, multiple sclerosis can be caused by both genetic and environmental factors. The disease results in the immune system attacking the protective sheath around the nerve fibres in our brain and spinal cord.


This can lead to nerve damage, resulting in communication problems between the brain and the rest of the body. Symptoms can include fatigue, impaired co-ordination, paralysis and vision loss.

One in every 1000 New Zealanders are affected by the disease, and at present there is no cure.

Added to many cleaning and painting products, solvents help to mix solid ingredients together into a liquid that can easily be spread over a surface. Once the product has been painted or wiped on an area, the solvent component evaporates, leaving an evenly applied dry coating.

Solvents affect us if we absorb them through our skin, or inhale them as they evaporate, causing irritation in our lungs.

Most of us are only exposed to solvents intermittently, through tasks such as painting our fingernails, polishing furniture or when we decorate our homes.

The National Occupational Health and Safety Advisory Committee, however, estimate that around 100,000 New Zealand workers are potentially exposed to organic solvents in their workplace at a more sustained – and so more dangerous - level.

Solvents are used in degreasing agents, paints, glues, in the manufacture of textiles, in plastics, polymers and in cosmetics like hair and beauty treatments.

Previous research that looked at retired electric utility workers and car spray painters found those working in solvent-filled environments showed reduced cognitive abilities such as memory loss and attention span.

New research published in the journal Neurology has discovered that people who work in industries where solvents are regularly used - spray painters, dry cleaners, hairdressers and beauticians for instance - are also much more likely to develop multiple sclerosis.


The researchers analysed almost 5000 participants, 2042 of whom had recently been diagnosed with multiple sclerosis and the remaining 2947 without the condition.

Using blood tests researchers were able to determine which of the participants carried the gene variants which increased their risk of the disease. A life history of the patient was then taken, which included whether the participant had ever smoked, and if they had ever been exposed to environments which used paints or solvents.

The study found people who carry genes that make them more at risk of multiple sclerosis are over six times more likely to develop the disease if they are also exposed to solvents.

When smoking was added to genetic predisposition and environmental solvent exposure, patients were 30 times more likely to develop the disease.

Even in people without the genetic predisposition, those who had worked in areas with regular exposure to solvents were still more likely to develop the condition.

The research suggests that the cocktail of constant lung irritation and inflammation from inhaling solvents and cigarette smoke could activate the immune system in a way that makes it more likely to trigger multiple sclerosis.

Wearing a respirator and gloves significantly reduces the symptoms of solvent neurotoxicity and should already be done in the workplace.

However, as we better understand the risks of solvent exposure, it might pay to open your windows and wear protection the next time you decide to paint anything from your house to your toenails.