Researchers have found nine different factors that can increase a man's risk of developing young-onset dementia.

With people living longer today, dementia has become a major health concern, with over 35 million people affected worldwide, including more than 40,000 people in Ireland.

According to researchers at Umeå University in Sweden, by 2050, an estimated 115 million people worldwide will have the condition. They decided to focus on young-onset dementia (YOD), which affects people under the age of 65.

They looked at almost 490,000 men who had been conscripted for Swedish military service between 1969 and 1980. At the time of conscription, they had an average age of 18. They were then followed up over a 37-year period, during which time, almost 500 developed YOD. Their average age when diagnosed was 54.

The researchers found that the risk factor most strongly linked to the development of YOD was alcohol poisoning. Those who had suffered alcohol poisoning were almost five times more likely to develop dementia.

Those who had used antipsychotic drugs, which are commonly used to treat mental health conditions such as bipolar disorder and schizophrenia, were three times more likely to develop YOD, as were those who had suffered a stroke.

Meanwhile those who had suffered with depression, or whose fathers had suffered with dementia, had twice the risk of developing YOD.

The researchers also recorded an increased risk of developing YOD if a person had used drugs other than alcohol, if they had impaired cognitive function, were short in stature or had high blood pressure.

The study found that altogether, almost seven in 10 cases of YOD were linked to these nine risk factors.

Overall, men with impaired cognitive function and at least two of the other nine risk factors were as many as 20 times more likely to develop dementia before the age of 65.

"The study shows that these independent risk factors are very important for the development of early dementia in men. Because most risk factors can be identified early in life, there are good opportunities to prevent disease progression," the researchers said.

Details of these findings are published in the journal, JAMA Internal Medicine.

For more information on dementia, see our Alzheimer's Clinic here