Depression and diabetes linked to higher risk of dementia, study finds

People with type 2 diabetes and depression may be at higher risk of developing dementia and people with both conditions at even greater risk, according to research published in JAMA Psychiatry today (Wednesday 15 April 2015).

Researchers at the University of Washington in Seattle examined the records of 2.4 million Danish citizens, who were 50 and older and initially free from dementia from 2007 through 2013.

The authors found that during the study period, 2.4 per cent of individuals (59,663 people) developed dementia and the average age at diagnosis was nearly 81 years. Of those individuals who developed dementia, 15,729 people (26.4 per cent) had depression alone and 6,466 (10.8 percent) had type 2 diabetes alone, while 4,022 (6.7 per cent) had both conditions.

The results of the study indicate that type 2 diabetes alone was associated with a 20 percent greater risk for dementia and depression alone was associated with an 83 percent greater risk, while having both depression and type 2 diabetes was associated with a 117 percent greater risk. The effect on risk for dementia appeared to be even greater among those study participants younger than 65.

Alzheimer's Society comment:

Dr Doug Brown, Director of Research and Development at Alzheimer's Society said:

'The more we learn about dementia the more we learn how other conditions may play a part in increasing risk of developing the condition. This study adds to a growing body of evidence that poorly managed type II diabetes and depression may increase risk and suggests that together, the two conditions could interact in a way that contributes to even greater risk. What's not clear cut is why. This is a complex area that we need to see more research into so that we can fully understand this link and what this means for us all.

Research such as this can help improve public health policy, but we don't want people with diabetes or living with depression to see this news and take it to mean that they're going to develop dementia. If you're concerned, contact your GP but in the meantime the best way to reduce risk of developing dementia is to eat a healthy balanced diet, take plenty of exercise, maintain a healthy weight and not smoke.'

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Research reference: Katon et al, (2014). 'Effect of Depression and Diabetes Mellitus on the Risk for Dementia: A National Population-Based Cohort Study'. Published in JAMA Psychiatry on Wednesday 15 April 2015.