Common class of drugs linked to increased risk of Alzheimer's disease


Date:
September 4, 2020
Source:
University of California - San Diego
Summary:
Researchers report that a class of drugs used for a broad array
of conditions, from allergies and colds to hypertension and
urinary incontinence, may be associated with an increased risk of
cognitive decline, particularly in older adults at greater risk
for Alzheimer's disease.



FULL STORY ==========================================================================
A team of scientists, led by researchers at University of California
San Diego School of Medicine, report that a class of drugs used for
a broad array of conditions, from allergies and colds to hypertension
and urinary incontinence, may be associated with an increased risk of
cognitive decline, particularly in older adults at greater risk for
Alzheimer's disease (AD).


==========================================================================
The findings were published in the September 2, 2020 online issue of
Neurology, the medical journal of the American Academy of Neurology.

Anticholinergic drugs are widely used for dozens of conditions, minor
and major. Some of these medications require a prescription, while others
can be purchased over the counter. They work by blocking acetylcholine --
a type of neurotransmitter or chemical messenger known to be critical for memory function -- from binding to receptors on certain nerve cells. The
effect is to inhibit parasympathetic nerve impulses, which are involved
in a variety of involuntary muscle movements, such as those in the gastrointestinal tract and lungs, and bodily functions like salivation, digestion and urination.

Researchers reported that cognitively normal study participants who were
taking at least one anticholinergic drug at baseline were 47 percent more likely to develop mild cognitive impairment (MCI), often a precursor to dementia such as AD, while being tracked over a period of up to a decade compared to participants who did not take such drugs.

"This study, led by Alexandra Weigand, suggests that reducing
anticholinergic drug use before cognitive problems appear may be important
for preventing future negative effects on memory and thinking skills, especially for people at greater risk for Alzheimer's disease," said
senior author Lisa Delano-Wood, PhD, associate professor in the Department
of Psychiatry at UC San Diego School of Medicine. Weigand is a graduate
student in the San Diego State University/ University of California San
Diego Joint Doctoral Program in Clinical Psychology.

Six hundred and eighty-eight adults were involved in the study, evenly
divided by sex with an average age of 74. None of the participants
displayed cognitive or memory problems at the beginning of the study. Each reported whether they were taking anticholinergic drugs. One-third were
taking such medications, with an average of 4.7 anticholinergic drugs
per person. Participants were given annual comprehensive cognitive tests
for up to 10 years.



==========================================================================
The scientists also looked at whether participants had biomarkers for
AD in their cerebrospinal fluid, such as certain types of proteins, or
a well-known genetic risk factor for AD. They found that participants
with AD biomarkers who were taking anticholinergic drugs were four times
more likely to develop MCI than persons lacking biomarkers and not taking
the drugs.

Similarly, persons at genetic risk for AD who took anticholinergic
drugs were approximately 2.5 times more likely to develop MCI than those without genetic risk factors and who were not taking the drugs.

"We believe this interaction between anticholinergic drugs and Alzheimer's
risk biomarkers acts in a 'double hit' manner," said Weigand, the study's
first author. "In the first hit, Alzheimer's biomarkers indicate that
pathology has started to accumulate in and degenerate a small region
called the basal forebrain that produces the chemical acetylcholine, which promotes thinking and memory. In the second hit, anticholinergic drugs
further deplete the brain's store of acetylcholine. This combined effect
most significantly impacts a person's thinking and memory." Study authors noted that, although older persons metabolize anticholinergic drugs
differently than younger people, anticholinergic medications were being
taken at levels much higher than the lowest effective dose recommended
for older adults, with 57 percent taken at twice the recommended dosage
and 18 percent at least four times the recommended dosage.

"This points to a potential area for improvement since reducing
anticholinergic drug dosages may possibly delay cognitive decline,"
said Weigand. "It's important for older adults who take anticholinergic medications to regularly consult with their doctors and discuss medication
use and dosages." Delano-Wood noted that more work is needed to examine
brain and cognitive effects of anticholinergic medications and whether
these medications accelerate age-related cognitive changes or directly
lead to neurodegenerative disorders, such as AD. "Clinical 'deprescribing' studies are currently underway at certain research sites across the
nation in an effort to investigate whether reducing or stopping use of
these drugs does, in fact, lead to reductions in progressive cognitive impairment," Delano-Wood said.

Co-authors include: Mark W. Bondi and Douglas R. Galasko, Veterans
Affairs San Diego Healthcare System and UC San Diego; Kelsey R. Thomas,
David P. Salmon, Daniel Sewell, James B. Brewer and Howard H. Feldman,
UC San Diego; and Noll L.

Campbell, Regenstrief Institute and Indiana University.


========================================================================== Story Source: Materials provided by
University_of_California_-_San_Diego. Original written by Scott
LaFee. Note: Content may be edited for style and length.


========================================================================== Journal Reference:
1. Alexandra J. Weigand, Mark W. Bondi, Kelsey R. Thomas, Noll
L. Campbell,
Douglas R. Galasko, David P. Salmon, Daniel Sewell, James B. Brewer,
Howard H. Feldman, Lisa Delano-Wood. Association of anticholinergic
medication and AD biomarkers with incidence of MCI among cognitively
normal older adults. Neurology, 2020; 10.1212/WNL.0000000000010643
DOI: 10.1212/WNL.0000000000010643 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/09/200904125116.htm

--- up 1 week, 4 days, 6 hours, 50 minutes
* Origin: -=> Castle Rock BBS <=- Now Husky HPT Powered! (1337:3/111)