SYDNEY, July 5 (Xinhua) -- Obstructive sleep apnea is linked to changes in brain structure in the early stages of dementia so screening older people for the sleeping disorder and treating it can help prevent the cognitive condition, according to a latest Australian research.

"Between 30 and 50 percent of dementia risk is due to modifiable factors, such as depression, high blood pressure, obesity and smoking. In recent years, researchers have recognized that various sleep disturbances are also risk factors for dementia," University of Sydney's Professor Sharon Naismith, who led the research, said in a statement on Thursday.

"We wanted to look specifically at obstructive sleep apnea and its effects on the brain and cognitive abilities."

Obstructive sleep apnea occurs when the walls of the throat relax and narrow during sleep, which stops breathing and is known to reduce blood oxygen levels.

The research involved more than 80 participants aged between 51 and 88 years who were assessed for their memory skills and symptoms of depression, with their brains scanned to measure the dimensions of different areas.

The findings, published in the European Respiratory Journal, showed that patients who had low levels of oxygen in their blood while they were sleeping tended to have reduced thickness in the left and right temporal lobes of the brain. The regions are known to be important in memory typically affected in dementia. The brain changes were also linked with participants' poorer ability to learn new information, reported the researchers.

There is no cure for dementia so early intervention is key, but effective treatment for obstructive sleep apnea is available, said Naismith. The research shows that diagnosing and treating the sleep disorder "could be an opportunity to prevent cognitive decline before it's too late," she said.