Dementia and Risk Factors

Dementia is affecting more than 55 million people worldwide. Alzheimer's disease (AD) constitutes more than half of all dementia. Within five years, one-third of patients with mild cognitive impairment (MCI) develop AD.

Age is a significant risk factor for dementia. A recent study published in Alzheimer's Research & Therapy demonstrated that a diagnosis of depression is associated with an approximately threefold increased risk for later MCI and almost twofold increased risk for later AD. The risk increased further if the patients also experienced chronic stress, as indicated by a recorded diagnosis of SED. Chronic stress and depression may be independent risk factors for dementia, and together, they may have an additive effect on the risk for later dementia.

It is already known that chronic stress and depression are potential risk factors for MCI and dementia, including Alzheimer's disease. This cohort study included 1,362,548 people with records in the Region Stockholm administrative healthcare database (VAL).

Exposure was a recorded ICD-10 diagnosis of chronic stress, depression, or both, recorded in 2012 or 2013. Alzheimer's disease diagnosis, dementia, or MCI recorded from 2014 through 2022 was the outcome. Odds ratios with 99% confidence intervals (CI) adjusted for age, sex, neighbourhood socioeconomic status, diabetes, and cardiovascular disorders were calculated.

Key Results of the Study

• 4,346 patients had chronic stress, 40,101 had depression, and 1,898 had both during exposure.
• The average age was 40 years at baseline in all groups.
• OR of Alzheimer's disease in patients with chronic stress, depression, and both were 2.45, 2.32, and 4.00, respectively.
• While OR of mild cognitive impairment was 1.87, 2.85, and 3.87 respectively.
• When other dementia was analyzed, the OR was significant only in patients with depression, 2.39.

"We found that documented chronic stress increased the risk of mild cognitive impairment and AD; the same is seen with depression," they said.

"We highlighted the potential additive effect of chronic stress to depression on the risk of MCI and AD," said Johanna Wallensten.

Reference

Wallensten, J., Ljunggren, G., Nager, A. et al. Stress, depression, and risk of dementia – a cohort study in the total population between 18 and 65 years old in Region Stockholm. Alz Res Therapy 15, 161 (2023). https://doi.org/10.1186/s13195-023-01308-4