Older people may reduce their risk of developing dementia if they go back to college, a new study suggests.

Australian researchers monitored the progress of 359 people aged between 50 and 79. All of the participants underwent extensive cognitive tests before completing at least one year of a full-time or part-time college course. They were then followed up for three years after they had completed their course.

The participants' progress was compared with the progress of a control group of 100 people who did not undertake a college course.

The study found that 92% of those who went back to college recorded a significant increase in their cognitive capacity, compared to just 56% of those in the control group. The remaining 8% of college students generally maintained their cognitive capacity.

Previous studies have shown that increasing cognitive capacity can help to slow down the cognitive decline associated with ageing. Cognitive decline or impairment is a risk factor for dementia, including Alzheimer's disease.

The participants' age, gender, levels of social connectedness and feelings of wellbeing did not affect the results.

"The study findings are exciting because they demonstrate that it's never too late to take action to maximize the cognitive capacity of your brain. We plan to follow these participants as they age to see if college studies could help delay the onset or reduce the debilitating effects of dementia," commented lead researcher, Dr Megan Lenehan, of the University of Tasmania.

The people who went back to college took a wide range of courses, including fine art, psychology and history. Most of the students went to college for their courses, although a few completed theirs online.

The researchers believe that studying on campus probably provides greater cognitive benefits because of the social interaction with students and lecturers involved. However, they did not investigate this.

Dr Lenehan noted that while previous studies have found that college courses can increase cognitive capacity earlier in life, this study shows the same is also true later in life.

"It is possible that any mentally stimulating activity later in life may also enhance cognitive capacity, such as other adult education classes or programmes to increase social interaction," she added.

Details of these findings are published in the journal, Neuropsychology.