Previous research has linked type-2 diabetes to increased risk of cognitive impairment, such as impaired decision-making and cognitive speed in older people. A study has also linked severe hypoglycaemic episodes in diabetes patients to poorer memory and diminished brain power.

For this latest study, King's College London researchers studied 61 people who had mild cognitive impairment and were aged over 65. Over a four-year period, 19 of the participants developed dementia. Diabetes was associated with a 2.9-times increased risk of developing dementia. Ten (16%) of those who completed the study had diabetes. Of those who developed dementia, seven (37%) had diabetes.

Writing in the British Journal of Psychiatry, the researchers said their findings showed that people with mild cognitive impairment and diabetes are at increased risk of developing dementia.

‘With an expected increase in prevalence of diabetes of people of all ages, including older adults, the risk of developing dementia may increase,' they said.

‘Identification of those at particular risk of progression to dementia might help to target early treatment,' the researchers added. ‘There is also a need for studies of improved diabetes control and related approaches as possible strategies for early intervention.'