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Systemic inflammation caused by rheumatoid arthritis could make cognitive decline more likely. Image credit: Juan Claudio Perez/Getty Images.
  • As of 2020, about 17.6 million people worldwide have the autoimmune disease rheumatoid arthritis.
  • Past studies have linked rheumatoid arthritis to an increased risk for a number of health concerns.
  • Researchers from the University of Málaga in Spain have now linked rheumatoid arthritis to a greater chance of developing specific cognitive impairments in older adults.

Rheumatoid arthritis is one of the most common autoimmune diseases affecting about 17.6 million people globally as of 2020.

There is currently no cure for rheumatoid arthritis. However, medications and lifestyle changes can be used to manage the inflammation and pain the disease causes to the body’s joints.

Past studies have linked rheumatoid arthritis to an increased risk for other health concerns including stroke, osteoporosis, dry eye disease, and certain cancers.

Now, a new study recently published in the journal RMD Open reports that people with rheumatoid arthritis may also have a greater chance of developing certain cognitive impairments later in life.

For this study, researchers recruited 140 participants with an average age of 56, 80% of whom were women. Half of the study participant pool had rheumatoid arthritis, while the other half did not.

Scientists reported that about three out of four, or 72%, of rheumatoid arthritis participants had moderate to high levels of systemic inflammatory activity caused by the disease.

All 140 participants took part in comprehensive neurological and psychological assessments, cognitive tests, and mood assessments at the beginning and end of the study.

Study participants were given scores for their cognitive ability based on the Montreal Cognitive Assessment (MoCA) test, where a score of less than 26 is considered a cognitive impairment.

Additionally, researchers tested participants for specific cognitive abilities including:

  • processing and ordering visuospatial information
  • memory
  • attention span
  • language abilities
  • abstract thinking
  • ability to recall information after being distracted
  • orientation — a person’s ability to explain what time, place, and situation they are in
  • executive functions of working memory, concentration, and inhibition.

At the study’s conclusion, researchers discovered that participants with rheumatoid arthritis had lower average Montreal Cognitive Assessment scores than those who did not, as well as lower scores for executive function.

Scientists reported recording cognitive impairment in 60% of rheumatoid arthritis participants, compared to 40% in healthy participants.

They also reported that participants with obesity and rheumatoid arthritis were almost six times more likely to develop cognitive impairment, and participants with rheumatoid arthritis and inflammatory activity during the course of their disease faced about double the risk of having cognitive issues.

When examining participants who tested for cognitive impairment, the researchers found that those participants had marked and persistent inflammation compared to those without cognitive issues.

In addition to rheumatoid arthritis, researchers also found that those at the highest risk of cognitive impairment were at an older age, had less education, and had other health concerns such as obesity, high blood fat levels, and high blood pressure.

Although inflammation is a natural part of the body’s defense system against germs and disease, chronic inflammation caused by diseases, environmental factors, and certain lifestyle habits such as not eating a healthy diet or getting enough physical activity can become a problem for the entire body.

Previous research has shown that inflammation anywhere within the body can have a negative impact on other areas.

For example, past studies have linked chronic inflammation to an increased risk for diseases like type 2 diabetes, depression, psoriasis, chronic obstructive pulmonary disease (COPD), and insomnia.

Additionally, previous research has linked chronic inflammation to neurological conditions, including dementia, Alzheimer’s disease, Parkinson’s disease, multiple sclerosis (MS), and Huntington disease.

“Recent studies have shown the critical contribution of inflammation in most, if not all, subtypes of dementias,” Karen D. Sullivan, PhD, ABPP, a board-certified neuropsychologist, owner of I CARE FOR YOUR BRAIN, and Reid Healthcare Transformation Fellow at FirstHealth of the Carolinas in Pinehurst, NC, who was not involved in this study, told Medical News Today.

“A better understanding of how inflammatory molecules lead to the ultimate death of networks of brain cells is certainly a needed piece of the puzzle to get to a cure,” she pointed out.

“By studying primary inflammatory conditions like rheumatoid arthritis, we will gain needed insights into the initial triggers that kick off inflammation in the central nervous system and subsequent downstream pathways that cause irreversible brain damage,” Sullivan added.

MNT also spoke with Xiaoyin Tang, MD, Rheumatology Section Chief at Hackensack Meridian Jersey Shore University Medical Center in New Jersey about this study.

Tang, who was not involved in this research, commented that this study provides a more comprehensive evaluation of cognitive function impairments in rheumatoid arthritis patients, and confirms the relationship between rheumatoid arthritis disease activity and cognitive function.

It also highlights the importance of controlling inflammation in people with rheumatoid arthritis, and validating the early diagnosis and treat-to-target approach in clinical practice, she added.

“As a clinical rheumatologist treating rheumatoid arthritis patients, our goal is to improve patients’ quality of life including physical and cognitive functions,” said Tang. “With more available treatment options in the biological agent era, we made tremendous improvement in rheumatoid arthritis patients’ physical functions.”

“Our general population, as well as rheumatoid arthritis patients are living longer. A lot of them will face a decline in cognitive functions at later stages of their life. Identifying the factors negatively impacting patients’ cognitive function [is] the first step [to finding] the solutions,” the doctor noted.

However, she emphasized that more research on the link between rheumatoid arthritis and brain health is needed:

“I would like to see further research looking into the effectiveness of aggressive treatments of rheumatoid arthritis to control inflammation in improvement of cognitive functions. I would also like to see research to compare different modalities of interventions with multidisciplinary approaches.”