A major review published by the Lancet Commission in June 2017 found nine risk factors that are associated with dementia. They focused on identifying risk factors that are “modifiable”, meaning that the person has control over and can possibly reduce the negative effects of those factors. The review revealed the Population Attributable Fractions (PAF) of each factor, which highlights the severity of the risk factor by estimating the number of new cases of dementia that could be prevented if no one had the risk factor. If all nine of those modifiable risks were eliminated, then 35% of dementia cases could be prevented. The other 65% are factors including family history and age which cannot be modified or controlled.
The nine modifiable factors and their estimated PAFs are below:
- Hearing loss (particularly hearing loss at mid-life) 9%
- Poor education 8%
- Smoking 5%
- Depression 4%
- High blood pressure 2%
- Social isolation 2%
- Physical inactivity (little to no exercising) 2%
- Type 2 diabetes 1%
- Obesity 1%
Of note, hearing loss at mid-life is the highest of these risk factors – it is estimated that if hearing loss was eliminated from the picture, then 9% of dementia cases could be prevented. Considering that depression, social isolation, and low education levels play a comparatively smaller role in developing dementia, then it becomes obvious that hearing loss is a huge factor for seniors who want to maintain their cognitive health. It is the biggest risk factor for which there is treatment and which can be controlled by the person.
There is currently no research to show that hearing loss can cause dementia, but there is certainly an overwhelming and growing body of evidence to show that hearing loss increases our chances of mental decline. If we want to take care of our mental health, make sure we do not neglect our hearing.
Livingston G, Sommerlad A, Orgeta V et al. Dementia prevention, intervention, and care. Lancet 2017;390(10113)2673–34.