A type of medication often used to treat diabetes could be crucial in the fight against Alzheimer's, a new study has revealed.
Scientists in South Korea have found that Actos, known medically as pioglitazone tablets which cost around 30p each, were found to halve the risk of developing dementia as it "slows" down mental decline.
The medication helps to control blood sugar levels by boosting the hormone insulin. Type 2 diabetes, the form caused by unhealthy lifestyles, affects 4.5 million people in the UK.
People that have this illness are twice as likely to develop dementia at some point in their lives.
Lead author of the study Dr Eosu Kim, of Yonsei University in South Korea, said: "Since dementia develops for years before diagnosis, there may be an opportunity for intervening before it progresses."
The findings were published in the journal Neurology.
The benefits of the medication were strongest for those who also had a history of stroke or ischaemic heart disease, which is a condition caused by narrowed arteries.
They were 43 and 54 per cent less likely to develop dementiarespectively.
This was after taking into account some potentially aggravating factors such as high blood pressure, smoking and physical activity.
Overall, incidence fell by 16 per cent among participants prescribed the drug - with cases falling the longer they taking it.
Case rates reduced 22 and 37 per cent in participants using the medication for two and four years, respectively.
The findings are based on 91,218 individuals in South Korea tracked for an average of ten years, 3,467 of whom received pioglitazone.
People taking the drug were also less likely to have a stroke.
Dr Kim said: "These results provide valuable information on who could potentially benefit from pioglitazone use for prevention of dementia.
"In some previous studies of people with dementia or at risk of cognitive decline who did not have diabetes, pioglitazone did not show any protection against dementia.
"So it is likely a critical factor affecting the effectiveness is the presence of diabetes. More research is needed to confirm these findings."
During the study, 8.3 per cent of those taking pioglitazone developed dementia, compared to ten percent not taking it.
The number of dementia cases worldwide is set to triple to more than 150 million by 2050. With no cure in sight, there is an increasing focus on protective lifestyle factors.
A healthy diet and plenty of exercise help ward off diabetes - and dementia.
Side effects of Actos include swelling, weight gain, bone loss and congestive heart failure.
More research is needed on the long-term safety of the drug and whether there is an optimal dose, said Prof Kim.
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