In this article, we’re bringing you advice from the 2024 Lancet Commission on dementia prevention, intervention, and care - a group of experts who have combed through massive amounts of previous research collected over decades to highlight 14 risk factors associated with dementia. The good news? Those 14 factors are things that can be modified. So making lifestyle changes around the factors identified here can help improve brain health, and potentially keep people that have the gene for Huntington’s disease (HD) healthy for longer.

Dementia vs HD

While HD and dementia may have different root causes, underlying factors that are beneficial for one will be beneficial for the other. Dementia is a general term for a reduced cognitive ability - the ability to think, remember, and reason.

A reduction in cognition is only one component of HD, which is caused by an inherited expansion of the genetic code in the huntingtin (HTT) gene. HD also affects a person’s mood and has a movement component similar to Parkinson’s disease, called chorea.

While there are currently no disease-modifying treatments for HD, there are several very promising ongoing clinical trials, such as those by uniQure, Wave Life Sciences, PTC Therapeutics, and Skyhawk Therapeutics. These companies are directly targeting the cause of HD, aiming to lower the HTT message. There are also companies with ongoing trials for drugs that would treat the cognitive aspect of HD, like Sage Therapeutics.

But we want to make sure that folks with the gene for HD stay as healthy as possible until we do have a disease-modifying treatment for HD in hand. So what active changes can people make to ensure that happens?

14 factors that affect brain health

1. Less education

People who have more childhood education and those who go on to attain higher education have a reduced risk of developing dementia. This could be because these groups are more likely to obtain more cognitively stimulating jobs, challenging their brain more frequently. Less education is considered a risk factor from early life that if rectified, would reduce the cases of dementia by 5%.

2. Hearing loss

It seems like a strange correlation, but the Commission found an association between dementia and hearing loss. While this is a factor typically associated with older people, age wasn’t the variable contributing to the risk of dementia here since they accounted for age. The authors think there could be social factors at play, such as isolation due to the inability to hear in social situations, leading to low mood and motivation. They also floated the idea of biological factors, such as vascular disease that could affect both the cochlea of the ear and the brain. However, none of those theories relating hearing loss to dementia have been proven. Hearing loss is considered a midlife risk factor, and eliminating it, for example with hearing aids, would reduce the number of dementia cases by 7%.

3. High blood pressure

People with untreated high blood pressure, aka hypertension, have an increased risk of dementia. However, this risk is lost when hypertension is treated with medication. The study specifically notes that risk of dementia increases when systolic pressure (the top number) is over 130. So getting blood pressure in check by age 40 so that it’s closer to 120/80 is good for your brain. Hypertension is a midlife risk factor that accounts for a 2% increase in dementia cases.

“So making lifestyle changes around the factors identified here can help improve brain health, and potentially keep people that have the gene for Huntington’s disease (HD) healthy for longer. ”

4. Physical inactivity

Exercise is tricky to measure since it varies so much across a person’s life, between cultures and socioeconomic status, and occurs at different intensity levels. However, the study shows that physical activity, particularly sustained physical activity across a person’s life, is associated with better cognition by the age of 69. The thought behind why exercise is so good for us is that it improves blood flow and reduces blood pressure, which could improve brain plasticity and reduce brain swelling - certainly things that could be beneficial for HD! Eliminating this midlife risk factor by living more active lifestyles could reduce the number of dementia cases by 2%.

5. Diabetes

While there’s a correlation between diabetes and increased risk for dementia, this appears to only be the case for diabetes acquired in midlife, not later than age 70. No one is sure why there is a correlation between diabetes and dementia, but they think it may be because of the effect that diabetes has on blood vessels, which run throughout the brain. It could also be because the brain requires insulin for metabolism and insulin resistance can lead to brain swelling. Improving health to eliminate type 2 diabetes in midlife could reduce dementia cases by 2%.

6. Social isolation

Infrequent social contact shows an increased risk for dementia. Criteria that counted toward social isolation were living alone, visits with friends and family less than once per month, and lack of participation in weekly group activities. Studies have found that socialization can improve the brain’s resilience to damage, promote healthy behavior, lower stress, and reduce inflammation. Eliminating social isolation in later life could reduce the number of dementia cases by 5%.

7. Excessive alcohol consumption

The report finds that heavy drinking comes with an increased risk for developing dementia compared to light drinking. Interestingly, not drinking at all had a higher risk for dementia than light drinking. A reason to imbibe?! Probably not. The jury is still out on how sound those findings are since various factors could be at play here, like not drinking because of alcoholism or other non-related health issues. Reducing alcohol consumption by midlife could reduce dementia cases by 1%.

8. Air pollution

Air quality is determined by the amount and size of particles in the air. Fine particles equal to or smaller than 2.5 μm are notoriously dangerous. The report found that sustained breathing of particles that are equal to or smaller than 10 μm increases the risk of developing dementia. Since there is a strong link between air quality and socioeconomic circumstance, developing policies and regulations around clean air will be important for reducing this risk for people from various social and geographical backgrounds. Having access to healthy air to breath later in life accounts for a 3% reduction in dementia cases.

9. Smoking

We now have an overwhelming amount of data to show that smoking is unequivocally bad for your health, and that includes your brain. Smoking increases the risk of dementia, with a higher risk for those who start smoking earlier. The good news is that this risk is only associated with current smokers; there was no increased risk of dementia between ex-smokers and people who had never smoked. Quitting smoking habits by midlife can reduce the cases of dementia by 2%.

10. Obesity

While obesity is associated with increased risk for dementia, this is a tricky factor to measure. Obesity is associated with other factors on this list, such as physical inactivity, diabetes, and high blood pressure. So it’s hard to tease out which is the factor really associated with dementia risk. However, most studies adjust for these other factors and obesity is still associated with higher dementia risk. Even a modest weight loss of 5 pounds improved cognition, suggesting that keeping an eye on your weight is good for your brain. Maintaining a healthy weight by midlife would reduce dementia cases by 1%.

11. Traumatic brain injury

Perhaps unsurprisingly, a bad knock on your noodle is bad for your brain! The study found that people who got a traumatic brain injury at younger ages were more likely to develop dementia. Avoiding traumatic brain injuries by midlife could reduce the number of dementia cases by 3%.

12. Depression

The report noted that the correlation between depression and dementia was bidirectional - that depression could be both a cause and consequence of cognitive changes. Theories about how depression could affect cognition relate to less self care and social contact, as well as biological factors like increased levels of the stress hormone cortisol that could affect the brain. Encouragingly, seeking treatment, like therapy, for depression by midlife could reduce dementia cases by 3%.

13. Vision loss

Vision loss was a new factor added since the 2020 Commission report. Specifically, they found an increased risk for dementia related to untreated vision loss. For conditions like cataracts where people sought treatment, there was no increased risk. But for people who had cataracts or diabetic retinopathy and didn’t seek treatment, there was an increased chance they would develop dementia. The report specifically noted the correlation wasn’t seen for other eye conditions, like glaucoma or age-related macular degeneration. Getting a handle on preventable vision loss by late life could reduce dementia cases by 2%.

14. High cholesterol

High LDL cholesterol is also a new addition since the 2020 report. Since then, studies have been done to show that high cholesterol is indeed associated with an increased risk for dementia. Taking a lipid-lowering drug, like statins that are widely prescribed to lower cholesterol, was not associated with an increased dementia risk. So the correlation seems to be with untreated high cholesterol. High LDL cholesterol is a midlife risk factor that if eliminated could reduce dementia cases by 7%.

What wasn’t included?

Notably absent from this list is sleep. HDBuzz has previously written about the importance of sleep for managing HD, tips and tricks for a good night’s sleep for people with HD, and biological reasons for why people with HD might have trouble sleeping. We also recently heard about sleep issues caused by HD and new drugs being developed for treatment at the Hereditary Disease Foundation conference.

However, there doesn’t yet seem to be a conclusive link between sleep disturbances and an increased risk for dementia. So far, studies haven’t been able to tease out how the risk for developing dementia might be associated with various facets of sleep, like duration compared to quality of sleep.

“It’s likely that these findings can be applied to HD as well - even if someone has the gene for HD, modifiable lifestyle choices could delay onset, increase healthy years, and reduce disease burden. ”

Diet was also not included as a risk factor in the report. While diet heavily plays into several factors on the list, like obesity and diabetes, there isn’t yet enough evidence for specific diets like the Mediterranean diet. However there’s lots of evidence that reducing consumption of ultra processed foods is good for overall health, so opting for an apple over chips will always be a good decision!

Surprisingly, even genetics can be overcome

The more surprising findings from the report are that developing dementia can be modified even for people who are at an increased genetic risk. The paper states that, “for the first time, it is clear that risk can be modified even in people with increased genetic risk of dementia.” It’s likely that these findings can be applied to HD as well - even if someone has the gene for HD, modifiable lifestyle choices could delay onset, increase healthy years, and reduce disease burden.

Since the previous report in 2020, the field has seen a massive expansion in the use and utility of biomarkers - biological changes that track with a disease and can be used to measure progression. Shockingly, there are many older people who have biomarkers of dementia, like amyloid plaques within their brains, who never go on to develop dementia. These findings strongly suggest that brain changes associated with dementia don’t mean that the disease is inevitable, supporting the 14 modifiable factors highlighted here.

Unsurprisingly, being healthy is good for you

This report from the Lancet Commission on dementia can not only be used by individuals to improve their own brain health, but it’s also used to guide policy changes at the national and international governmental levels. This could take the form of prioritizing early education across socioeconomic backgrounds, destigmatizing and encouraging seeking help for mental health, and enacting helmet laws for contact sports and bicycles.

Overall, the report shows what people certainly already know - living a healthy lifestyle and being kind to yourself will give you more healthy years. Things that are good for your brain, like education and preventing brain injury, will keep your brain healthy. And things that are good for your heart, like exercise, not smoking, and less alcohol, are also good for your brain.

You may have also noticed that each of these factors is relatively small by comparison – a few percentage points here or there, with the highest being 7%. So even if someone can’t check off every factor on the list, their chances of developing dementia are still low. It’s when health issues compound that the risk for developing dementia really increases. The take home message here is take care of – and be kind to – yourself.

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