MS 'linked to anaesthetic gases'

Patients are not at risk from anaesthetic gases

Exposure to anaesthetic gases at work could triple the risk of developing multiple sclerosis, researchers claim.

A small study of nurse anaesthetists in Sweden made the link.

Researchers say it highlights the risks associated with the commonly used anaesthetic gases.

But MS and anaesthetic experts warn the finding is not backed up by other studies.

Exposure

Anaesthetic gases are organic solvents. Previous research suggested exposure to the solvents doubled the risk of developing multiple sclerosis (MS)

This is a localised finding

Professor Peter Hutton, Royal College of Anaesthetists

Eighty-three nurses with MS, who had responded to appeals in magazines published by the Swedish Nurse Union and the Neurological Patients' Association in Sweden, were surveyed.

Thirteen were nurse anaesthetists.

They were asked about their jobs, the extent of their exposure to anaesthetic gases, and the timing of symptoms and diagnosis of MS.

Eleven nurse anaesthetists had been exposed to anaesthetic gases before their MS was diagnosed, for an average of 14 years.

Ten of those were diagnosed between 1980 and 1999, and were three times as likely to develop MS compared with the general population.

Patients were not at risk, say the researchers, because they are not repeatedly exposed to the gases, as staff are.

Controls

Dr Ulf Flodin, of the Department of Occupational and Environmental Medicine, University Hospital, in Linköping, Sweden told BBC News Online: "There is doubt about the link but, in my opinion, there is a strong association"

Writing in the journal Occupational and Environmental Medicine, the researchers, from the admitted their analysis was based on "crude" data and was "somewhat approximate".

But they add: "This study provides preliminary evidence for an excess risk of MS in nurse anaesthetists."

They are calling for tighter controls on the levels of circulating anaesthetic gases in operating theatres and better ventilation to minimise the risks.

Concern

Chris Jones, chief executive of the MS Trust, told BBC News Online: "Until we know the cause for MS, or course there are going to be different hypotheses put forward.

"This is certainly one that has had some airing over the last five years."

She added: "Obviously the findings of this research give cause for concern.

"However, we should bear in mind that the sample is very small - 83 nurses.

"We would need to see these figures replicated over a much larger population before reaching any firm conclusions."

Professor Peter Hutton, president of the Royal College of Anaesthetists, said: "This is a localised finding, and has never been found before in larger studies that have been carried out on a worldwide basis.

"If you did have this increase in MS, you would see it in anaesthetists as well, and there's no evidence of that."

He said demands on anaesthetists in the next decade had led the college to consider the idea of introducing non-medical anaesthetic staff.