Women are at increased risk of developing multiple sclerosis if they take the contraceptive pill, according to a new joint study from the US and Argentina.
Rates of the incurable degenerative disease are already higher amongst women than men, but researchers at the Kaiser Permanente medical centre in Oakland, California and the Raul Carrera Institute of Neurological Research in Buenos Aires believe those on the pill are at the greatest risk.
Women that are overweight were also identified has having a higher chance of getting disease, perhaps because they produce greater levels of a hormone that regulates their appetite.
The study, which was unveiled to delegates at the American Academy of Neurology’s annual meeting in Philadelphia, is in stark contrast to previous research which suggested that the contraceptive pill could actually cut the risk.
Some 305 women with MS were assessed as part of the study. Over a period of three years, their use of the pill was compared with over 3,000 people without the illness.
Some 29 per cent of those with MS were found to have been taking contraceptives for at least three months before their symptoms were identified.
Lead researcher Dr Kerstin Hellwig said: "These findings suggest that using hormonal contraceptives may be contributing at least in part to the rise in the rate of MS among women.
"We don’t say it causes MS, but adjusting for other factors more women use the pill who develop MS."
She added that some environmental factors may also play a part so at this stage it would not be correct to tell women to stop using the pill.
MS affects around 100,000 people in the UK, with around 50 young people being diagnosed every week.
That said, a recent study conducted by researchers in Scotland found that the number of people being diagnosed fell by an average of three per cent per year between 1990 and 2010.
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