Estimates from 2010 had put the figure at 70,000, but GP records revealed 110,000 are thought to be affected. Researchers at the University of London said that increasing life expectancy and an ageing population may be behind the spike.
Muscular Dystrophy UK used the team’s study of healthcare records from 2000-2019 to calculate the figure.
It then excluded other conditions such as Guillain-Barre syndrome and motor neurone disease.
The charity’s chief executive, Catherine Woodhead, said neuromuscular services must be given more resources.
She added: “It is vital these findings are engaged with as a matter of priority.”