The actress, now 72, was diagnosed with the life-threatening disease. eight years ago and says she "foolishly refused to take the diagnosis seriously".
"The doctor told me to take a daily pill to help stop my bones getting any weaker and to take calcium to help keep them strong," the Daily Express quoted her, as saying.
However, she didn't pay attention to the advice and now the disease is ravaging her body.
"I don't want to become a crippled old lady, bent double, who can only shuffle along."
Ursula, who played Honey Rider in the 1962 film opposite Sean Connery, said, has been told her bones are so brittle, she could easily break a hip from even a gentle fall.
And now, she regrets ignoring doctors' advice after a scan revealed her condition.
"I found it so strange because I had no pain, no warning.You don't realise your bones are becoming like glass," she said.
I've always been sporty and done lots of exercise. I've always eaten well, including dairy and calcium-rich foods but that is the nature of the disease - you carry on as normal and you don't realise your bones are becoming like glass," she added.
Ursula is now following a strict regime she wishes she had adopted eight years ago.
"Years ago, with the pills, I would think, 'I will take it later' and it would get later and later and days passed without me taking the medication," she said.
"I am passionate about life and my garden at home in Italy. I would be so embarrassed if I had to depend on anyone to help me with day-to-day life," she added.