FEB 20, 2019 6:30 PM PST

Silent Inflammation, the Silent Problem

WRITTEN BY: Nicholas Breehl

People who have chronic inflammation in middle-age may develop problems with thinking and memory in the decades leading up to old age, according to a new study published in the February 13, 2019, online issue of Neurology®, the medical journal of the American Academy of Neurology.

There are two kinds of inflammation. Acute inflammation happens when the body's immune response jumps into action to fight off infection or an injury. It is localized, short-term and part of a healthy immune system. Chronic inflammation is not considered healthy. It is a low-grade inflammation that lingers for months or even years throughout the body. It can be caused by autoimmune disorders like rheumatoid arthritis or multiple sclerosis, physical stress or other causes. Symptoms of chronic inflammation include joint pain or stiffness, digestive problems, and fatigue.

Ways to reduce chronic inflammation include getting regular exercise, following a heart-healthy anti-inflammatory diet, and getting enough sleep.

"Chronic inflammation is tough on the body, and can damage joints, internal organs, tissue, and cells," said study author Keenan A. Walker, Ph.D., of Johns Hopkins University in Baltimore, Md. "It can also lead to heart disease, stroke, and cancer. While other studies have looked at chronic inflammation and its effects on the brain in older people, our large study investigated chronic inflammation beginning in middle age and showed that it might contribute to cognitive decline in the decades leading up to old age."

As part of the Atherosclerosis Risk in Communities (ARIC) Study, researchers followed 12,336 people with an average age of 57 for approximately 20 years. Researchers took blood samples from participants at the start of the study, measuring four biomarkers of inflammation: fibrinogen, white blood cell count, von Willebrand factor, and factor VIII. They created a composite inflammation score for the four biomarkers. Three years later, researchers measured C-reactive protein, another blood biomarker of inflammation. Participants were divided into four groups based on their composite inflammation scores and C-reactive protein levels.

Participants' thinking and memory skills were tested at the beginning of the study, six to nine years later, and at the end of the study.

Researchers found the group with the highest levels of inflammation biomarkers had an 8-percent steeper decline in thinking and memory skills throughout the study than the group with the lowest levels of inflammation biomarkers. The group with the highest C-reactive protein levels had a 12-percent steeper decline in thinking and memory skills than the group with the lowest levels. These results were derived after researchers adjusted for other factors that could affect thinking and memory skills, such as education, heart disease, and high blood pressure. Further analyses revealed that inflammation-associated declines in thinking were most prominent in areas of memory, compared to other aspects of thinking such as language and executive functioning.

"Overall, the additional change in thinking and memory skills associated with chronic inflammation was modest, but it was greater than what has been seen previously associated with high blood pressure in middle age," Walker said.

"Many of the processes that can lead to a decline in thinking and memory skills are believed to begin in middle age, and it is in middle age that they may also be most responsive to intervention," said Walker. "Our results show that chronic inflammation may be an important target for intervention. However, it's also possible that chronic inflammation is not a cause and instead of a marker of, or even a response to, neurodegenerative brain diseases that can lead to cognitive decline."

A limitation of the study was that participants with higher levels of chronic inflammation at the start of the study were more likely to drop out or die before the final follow-up visit, so surviving participants may not be representative of the general population.

Future studies could include more frequent assessments of thinking and memory skills. They could also examine a more extensive variety of inflammation markers in the blood.

Sources: Science Daily, Neurology, YouTube

About the Author
You May Also Like
JUL 29, 2020
Immunology
Immune Variation Explains Different COVID-19 Outcomes
JUL 29, 2020
Immune Variation Explains Different COVID-19 Outcomes
Immune systems respond differently to coronavirus infection. People experience the disease causes by coronavirus, COVID- ...
OCT 14, 2020
Immunology
Happiness Linked to Heart Attack Risk
OCT 14, 2020
Happiness Linked to Heart Attack Risk
Asking patients questions about their personal lives could predict their future risk of a heart attack. A study, publish ...
OCT 12, 2020
Genetics & Genomics
The Malaria Parasite Can Change Host Cell Genetics
OCT 12, 2020
The Malaria Parasite Can Change Host Cell Genetics
Mosquitoes can transmit the malaria-causing Plasmodium parasite to humans. Malaria was estimated to have caused the deat ...
OCT 12, 2020
Microbiology
Researchers May Have Found a Way to Cure Rotavirus Infections
OCT 12, 2020
Researchers May Have Found a Way to Cure Rotavirus Infections
Rotaviruses are very contagious. They are the most common cause of diarrhea in children and are estimated to cause about ...
NOV 09, 2020
Drug Discovery & Development
New Immunotherapy Shows Promise for MS
NOV 09, 2020
New Immunotherapy Shows Promise for MS
Researchers from Thomas Jefferson University in Philadelphia are studying an immunotherapy that has shown early pro ...
NOV 10, 2020
Immunology
Genetic Profiling Reveals How Ebola Puts Immune Cells in a Chokehold
NOV 10, 2020
Genetic Profiling Reveals How Ebola Puts Immune Cells in a Chokehold
In the middle of 2020, yet another deadly Ebola outbreak was reported in the Democratic Republic of the Congo - the 11th ...
Loading Comments...