Dementia is spreading dramatically to people in their 40s and 50s. The National Health Insurance Corporation said Sunday the number of patients diagnosed and treated for dementia in hospitals increased 3.7 fold from 47,747 in 2002 to 175,749 in 2008

Those aged 65 or older led the increase, with their number increased 4.03 times from 39,589 in 2002 to 159,699 in 2008. But the number of dementia patients in their 40s and 50s also jumped 2.3 times from 3,546 to 8,266. An NHIC official said, "The fact that an increasing number of people in their 40s and 50s suffer from intense stress, high blood pressure and diabetes explains the trend."

The number of patients of geriatric diseases such as dementia, Parkinson's disease and cerebrovascular diseases rose by 90.8 percent from 499,000 in 2002 to 952,000 in 2008. Cerebrovascular disease patients were the largest group among those who were treated with 757,000 in 2008.