According to a new study by the National Academies of Sciences, Engineering, and Medicine, treating conditions that appear alongside age-related cognitive decline may help reduce future cases of Alzheimer’s disease, these conditions including type 2 diabetes and depression.
The National Academies of Sciences, Engineering and Medicine released the report explaining that by hypertension management, increased physical activity, and cognitive training patients could potentially prevent Alzheimer’s disease.
Currently, there are only theories regarding the disease’s origin and treatments. The study only shows “modest but inconclusive evidence.”
Not nearly enough evidence, but definitely on the right path
Despite the insufficient evidence, researchers are confident that these practices are effective and that they should be followed regardless of the person’s age or state of health. Furthermore, the study reflects on other conditions that are present in most cases of age-related dementia, such as type 2 diabetes, sleep quality, social engagement, and depression.
Up until 2010, studies have concluded that researchers cannot make recommendations regarding methods to prevent Alzheimer’s. Now there is a significant increase in the data available to understand what causes dementia and cognitive decline.
“There is a critical need for pharmacological treatments that, though not preventing disease, can delay onset of dementia or slow progression of cognitive impairment. Although such treatments are not prevention interventions in the strict sense, they can be thought of as secondary or tertiary prevention,” reads the study.
The few recommendations doctors can make have to rely on limited randomized controlled trials (RCTs), which are the “gold standard of evidence” when it comes to medical research.’
The first recommendation is managing blood pressure for people with hypertension, especially in people aged between 35 and 65. The report reads that managing hypertension ” is supported by encouraging but inconclusive evidence” when it comes to preventing Alzheimer’s disease. Researchers are not sure whether if hypertension or its preventive methods can be associated with an increased or lower risk of suffering Alzheimer’s.
They also recommend physical activity, which is helpful to prevent conditions that could be related to suffering Alzheimer’s, such as a stroke, which can cause irreparable damage to the brain. Randomized controlled trials suggest that increased physical activity is effective in delaying age-related cognitive decline, although the results were “not consistently positive.”
Lastly, cognitive training is an item of interest and debate in the scientific community. Despite the benefits of cognitive training when it comes to short-term tasks, its advantages in the long term are not clear. Trials suggest that cognitive training may improve long-term cognitive function and help maintain independence over the person’s daily life. But, just like in the previous two recommendations, cognitive training in RCTs yielded mixed results.
The study includes social engagement within “cognitive training,” pondering whether the social aspect of a task can increase the training’s adherence. Additionally, researchers believe that studies should prioritize looking into slowing the progression of Alzheimer’s disease and how it can associate with diabetes, depression, diet, sleep quality, social engagement, and vitamin B12 and folic acid ingestion.
Due to the lack of consensus, the National Institutes of Health suggests that future studies should increase the participation of underrepresented populations, including younger patients and having longer follow-up periods.
Diabetes, depression and cognitive decline
The current hypothesis suggests that beta-amyloid plaques in the brain could be the main contributor to Alzheimer’s disease since they are present whenever a person receives its diagnosis. Beta-amyloid is a soluble protein that for some reason accumulates in the brain, creating small plaque-like structures that bind to nerve cells. The plaques start a “cascading chemical reaction” resulting in the erosion of the neurons’ synapses, causing the person to lose control of its nerve functions.
In the most recent study, researchers claim that high insulin levels (the main contributor to developing type 2 diabetes) may increase amyloid accumulation in the brain, therefore potentially increasing the risk of suffering from Alzheimer’s. In 2011, nearly 175,000 cases of Alzheimer’s in the U.S. were associated with diabetes.
But again, despite the uplifting evidence, researchers argue that it is not enough to prevent diabetes to reduce the risk of suffering from Alzheimer’s; mainly because diabetes drugs might also lower the risk:
“Although results of RCTs of diabetes treatment for preventing cognitive decline and dementia have not been encouraging, other sources of evidence indicate that further study of such interventions is warranted. It is biologically plausible that a decrease in insulin levels through pharmacologic or nonpharmacologic means could prevent cognitive decline and dementia.”
Studies also associate depression to cognitive decline and dementia, attributing 15 percent of Alzheimer’s cases in the U.S. to depression. Apparently, depression can cause an increase in cortisol levels, which can indicate atrophy of the hippocampus, a brain structure that controls learning and memory.
The problem with depression is that it’s extremely troublesome to study in control trials. Still, researchers argue that there is potential to prevent cognitive decline and dementia by treating depression, even if the available evidence is limited. A 2007 study using RCTs found a significant improvement in cognitive function in patients aged 65 to 90 when researchers used a hormone inhibitor to treat their depression.
Finding the cure for Alzheimer’s may not be the next step in the list, as researchers still need to comprehend how the disease affects the brain. Fortunately, they do have important clues of where to start looking.