Five Risk Factors for MCI

Who is most likely to develop MCI? In this posting, we talk about five risk factors for MCI and what you can do about (many of) them.

1. Age – the older you are, the more likely you are to develop MCI. By living longer we have the chance to be exposed to more physical, psychological, and emotional changes that can increase our MCI risk.

2. Genetics – Carriers of the e4 allele of the apolipoprotein E gene (APOE-4 for short) are more likely to develop MCI. We all carry two alleles of the APOE gene, and each can be an e2, e3, or e4. The fact that carrying an e4 allele is a risk factor for MCI is not too surprising, given that this allele has been associated with an increased risk of Alzheimer disease.

3. Lack of Intellectual Engagement (for example, formal education, lifelong learning, joining a book club, organizing a fundraiser) – Research has shown that the fewer years of formal education you have, and the less intellectually engaged you are in adulthood, the more likely you are to develop MCI. Brain imaging shows quite clearly that the harder the cognitive task, the more it is a work out for the brain – blood flow and metabolism increase in the brain areas doing the heavy lifting. Education and intellectual engagement are thought to foster more and denser connections between brain cells.

4. Metabolic Health – Conditions such as hypertension, diabetes, obesity, smoking, and high cholesterol are associated with an increased risk of MCI. We tend to forget that these sorts of conditions don’t just affect the vascular system from the neck on down, but that they affect our brains as well. These conditions increase risk of both a major stroke and small lesions in the white matter (the connections between neurons) that can affect cognition.

5. Depression – People with depression are more likely to develop MCI. This could be because depression makes people vulnerable to cognitive decline, because depression is a common response to early cognitive changes, because depression is a symptom of the brain changes that occur with MCI (particularly damage to the hippocampus, which is important for memory and is very sensitive to stressors), and/or because people with metabolic conditions listed above are more likely to have depression.

So, now that you know this, what to make of it? If your mother had dementia and you didn’t finish high school and you have metabolic risk factors and battle with depression, does that mean you are certain to develop MCI? Or, if you’re a 65 year old with no family history of dementia, you finished college and you’re in good physical and mental health are you off the hook?

The answer to both is no. Scientists discover risk factors by examining large groups of people and then through statistics identify which factors are associated with an increased risk of MCI, but that doesn’t mean that the risk factors apply to every individual person. That is because risk factors are just that – they are risk factors, not causal factors. That is, none of these factors directly cause MCI, but they do make it more likely.

An important point is that some of these risk factors are modifiable, but others are out of your control. You obviously can’t do anything about getting older, or about what genes your parents passed down to you, but you often can do something about your lifestyle and your physical and mental health that will help reduce your risk of developing MCI.

Remember, the opposite of a risk factor is a protective factor – if being cognitively sedentary is a risk factor, being cognitively engaged is a protective factor. That is why it is worth addressing the modifiable risk factors to help reduce your risk of developing MCI and increase your chance of living in good brain health.