An American study has shown that middle-aged people who smoke, have high blood pressure, or diabetes increase their risk of developing dementia.
The US study of more than 11,000 people aged between 46-70 is reported in the Journal of Neurology, Neurosurgery and Psychiatry.
Researchers from the universities of Minnesota and North Carolina, along with John Hopkins Hospital and the University of Mississippi Medical Center have found that under-55s who smoke increase their risk of developing dementia five-fold and those with diabetes more than triple their risk.
The study took place over a period of 12 to 14 years and 203 participating in the study developed dementia. Researchers say that lifestyle factors during middle age appeared to play an important role in this.
Smoking, high blood pressure and diabetes are all linked to dementia because they all damage the small blood vessels that supply the brain.
The statistics showed that smokers were 70 percent more likely than non smokers to develop dementia, people with high blood pressure were 60 percent more likely to develop the condition than those with normal blood pressure levels. People with diabetes were more than twice as likely to develop the condition than those without diabetes.
Figures from the Alzheimers Research Trust state that there are 700,000 people living with dementia in the UK today, a number forecast to double within a generation.
Previous research into the condition has shown that brain exercises such as card games may delay dementia onset.
This latest study suggests that addressing unhealthy lifestyles during middle age may also reduce the risk of some people developing the condition.