Cancer patients had a slower rate of cognitive decline both before and after diagnosis compared to people who did not have cancer, according to a 2019 cohort study. Furthermore, previous research has shown an inverse link between cancer and Alzheimer’s disease, and this study provides additional support for this association.
The Study: Participants and Assessments
The study cohort comprised 14,583 adults from the Health and Retirement Study. All of them were born before 1949 and had no diagnosis of cancer by 1998. The researchers followed and examined the participants closely from 1998 to 2014. During those 16 years, 12,333 participants remained healthy, while a total of 2,250 developed cancer.
A survey conducted in 1998 helped set a baseline; during the follow-up session, either in-person or over-the-phone biennial interviews took place to collect more information, such as whether a participant had received a cancer diagnosis. For adults who were too ill and impaired to answer by themselves, the researchers permitted proxy interviews.
The assessment of memory function persisted throughout the follow-up period. To analyze overall memory function, each participant had to memorize and reiterate a 10-word list both immediately and after a specific period of time. For patients who were too impaired, a stand-in helped evaluate the participant’s cognitive function and memory according to a 5-item Likert scale and finish the 16-item Informant Questionnaire for Cognitive Decline.
The Results: Cognitive Impairment Develops Slowly in Cancer Patients
The study’s findings are an important contribution to our literature, said Jane Driver, MD, Division of Aging, Brigham and Women’s Hospital to JAMA Cancer Network. “The study provides a level of evidence that’s stronger than a lot of prior studies, which were really only able to look at overall associations using diagnoses. Here, we have a diagnostic test that’s actually measuring cognition and its change over time.”
The researchers revealed that before becoming diagnosed with cancer, the participants had a 10.5 percent slower rate of memory decline in comparison to participants who remained healthy or cancer-free. Following a new cancer diagnosis, the memory seemed to decline, but the overall effect was transient. On the other hand, cancer survivors had a 3.9 percent slower rate of memory decline when compared with cancer-free men and women.
Driver said this is a cohort study and the authors successfully looked at large numbers of patients, which is “really necessary” to find answers to the question of whether poor memory and cancer have an inverse relationship. Moreover, Driver praised the study authors’ inclusion of cognitive assessments over time.
“Both before and after the cancer diagnosis, overall, people who develop cancer seem to develop cognitive impairment more slowly than the comparison subjects,” acknowledged Driver. “It suggests that there’s something to this inverse association, and that maybe it’s not all due to some kind of a bias, which many people have attributed this relationship to over the years.”
Regarding the proxy assessments, Driver was not too critical, explaining that it’s expected when people grow older and their cognition worsens. It’s understandable that they were going to need representatives to give the necessary information.
Importance of the Study and Its Findings
The takeaway is that it’s worth pursuing these underlying biological explanations because even though the available treatments for malignant diseases are expanding, one effective treatment for Alzheimer’s disease does not exist. “I think many of us are hoping that further investigation of this strange association would perhaps lead us closer to a treatment for Alzheimer’s disease, or at least help us understand it better than we have so far,” concluded Driver.
How to Prevent Alzheimer’s and the Possibility of Cancer
Fortunately, healthy habits may help thwart Alzheimer’s disease. Consider these tips to prevent dementia, according to Harvard Health Publishing.
“The most convincing evidence is that physical exercise helps prevent the development of Alzheimer’s or slow the progression in people who have symptoms,” explains Dr. Gad Marshall, associate medical director of clinical trials at the Center for Alzheimer Research and Treatment at Harvard-affiliated Brigham and Women’s Hospital. “The recommendation is 30 minutes of moderately vigorous aerobic exercise, three to four days per week.”
- Eat a Mediterranean diet
A Mediterranean diet may help prevent Alzheimer’s disease or slow its progression. Even partial adherence to this diet can be better than nothing, which is important for people who may find it challenging to commit to a new diet. The diet includes fresh fruits and vegetables; whole grains; nuts; legumes; olive oil; fish; moderate amounts of dairy, eggs, and poultry; moderate amounts of red wine; and sparing amounts of red meat, as too much red meat is a known risk factor for many diseases, including cancer.
- Get enough sleep
Growing evidence suggests that getting quality sleep at night may help prevent Alzheimer’s. Sleep is also associated with greater amyloid clearance from the brain, asserted Dr. Marshall. Therefore, aim for seven to eight hours of sleep every night, especially since sleep deprivation may cause cancer.
- Engage the brain by learning new things
Activities that stimulate the mind, such as reading, playing word games, and completing puzzles, may help prevent Alzheimer’s. However, in general, the evidence supporting the benefit of cognitively stimulating activities is often “limited to improvement in a learned task, such as a thinking skills test, that does not generalize to overall improvement in thinking skills and activities of daily living,” explained Dr. Marshall.
- Connect socially
Greater social contact may help prevent Alzheimer’s disease, said Dr. Marshall, but so far, there is only information from observational studies. Regardless, being social has many health benefits, including pain relief, a strengthened immune system, and a reduced risk of stroke.
A Final Word
Alzheimer’s is the most common form of dementia, which occurs due to the accumulation of two types of protein in the brain: plaques (amyloid-beta) and tangles (tau). As the disease progresses, it kills brain cells and takes people’s lives. The latter may happen sooner if the patient also has cancer.
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