Brain with DNA and inflammation effects

Is Your Brain's 'Inflammation Switch' Causing Cognitive Decline?

Rhea Morgan in Health & Wellness December 2025 • 4 min read.

"New research links a common gene variation impacting IL-6 production to increased risk of cognitive decline in older adults, even without dementia."

As we age, maintaining sharp cognitive function becomes a top priority. While factors like genetics and lifestyle are known to play a role, emerging research is uncovering more intricate details about the aging brain. One such area of interest involves inflammation, and specifically, the role of a molecule called interleukin-6 (IL-6).

IL-6 is a pro-inflammatory cytokine, meaning it's a signaling molecule that promotes inflammation. While inflammation is a natural part of the body's immune response, chronic or excessive inflammation in the brain has been linked to neurodegenerative processes. Scientists are particularly interested in how variations in the genes that control IL-6 production might influence cognitive health.

Now, a new study sheds light on this connection. Researchers have found that a common variation in the IL-6 gene is associated with a greater risk of cognitive decline in older adults who already have some degree of cognitive impairment, but not dementia. This article breaks down these findings, explaining what they mean for your understanding of brain health and aging.

The IL-6 Gene Variation: What It Means for Your Brain

The study focused on a specific variation in the IL-6 gene, called -174 G > C. Genes come in different versions, or alleles, and this variation refers to a change at a specific location in the DNA sequence of the IL-6 gene. Individuals can have different combinations of these alleles (GG, GC, or CC).

Here's the key finding: the researchers discovered that older adults with existing cognitive impairment, but no dementia, who carried at least one copy of the 'C' allele (GC or CC) were more likely to experience a decline in their overall cognitive scores over a one-year period. Those with the 'GG' combination were more likely to remain stable or even improve.

The 'C' allele is associated with increased IL-6 production.
Higher IL-6 levels, driven by this genetic variation, might contribute to a pro-inflammatory environment in the brain.
This inflammation could accelerate cognitive decline in vulnerable individuals.

It's important to remember that this study doesn't mean everyone with the 'C' allele is destined for cognitive decline. It simply suggests an increased risk. Other factors, such as lifestyle, diet, and other genes, also play significant roles.

What Does This Mean for You?

This research adds to the growing body of evidence highlighting the role of inflammation in brain aging and cognitive decline. While you can't change your genes, understanding your potential risk factors can empower you to make informed choices about your health.

While genetic testing for this specific IL-6 variation isn't yet a standard recommendation, this study underscores the importance of adopting brain-healthy habits. These include:

<ul> <li>Maintaining a healthy diet rich in antioxidants and anti-inflammatory foods.</li> <li>Engaging in regular physical exercise.</li> <li>Challenging your brain with mentally stimulating activities.</li> <li>Managing stress and prioritizing sleep.</li> <li>Working with your doctor to manage any underlying health conditions that could contribute to inflammation.</li> </ul>

About this Article -

This article was crafted using a human-AI hybrid and collaborative approach. AI assisted our team with initial drafting, research insights, identifying key questions, and image generation. Our human editors guided topic selection, defined the angle, structured the content, ensured factual accuracy and relevance, refined the tone, and conducted thorough editing to deliver helpful, high-quality information.See our About page for more information.

This article is based on research published under:

DOI-LINK: 10.1590/0004-282x20150137, Alternate LINK

Title: Genetic Predisposition To Higher Production Of Interleukin-6 Through -174 G ≫ C Polymorphism Predicts Global Cognitive Decline In Oldest-Old With Cognitive Impairment No Dementia

Subject: Neurology

Journal: Arquivos de Neuro-Psiquiatria

Publisher: FapUNIFESP (SciELO)

Authors: Vanessa G. Fraga, Henrique C. Guimarães, Antônio L. Teixeira, Maira T. Barbosa, Elvis C. C. Mateo, Maria G. Carvalho, Paulo Caramelli, Karina B. Gomes

Published: 2015-11-01

Everything You Need To Know

What is Interleukin-6 (IL-6) and why is it relevant?

The molecule, Interleukin-6 (IL-6), is a pro-inflammatory cytokine. It's a signaling molecule that promotes inflammation. While inflammation is a natural part of the body's immune response, chronic or excessive inflammation in the brain has been linked to neurodegenerative processes. Scientists are particularly interested in how variations in the genes that control IL-6 production might influence cognitive health. The IL-6 gene variation influences the production of this molecule.

What is the specific IL-6 gene variation discussed and how does it work?

The specific genetic variation discussed is called -174 G > C. This is a change at a specific location in the DNA sequence of the IL-6 gene. People can have different combinations of alleles, which are different versions of a gene (GG, GC, or CC). The presence of the 'C' allele (GC or CC) is associated with increased IL-6 production, potentially leading to a pro-inflammatory environment in the brain, which could accelerate cognitive decline in individuals with existing cognitive impairment.

What are the potential implications of having the 'C' allele of the IL-6 gene variation?

If an individual has the 'C' allele (GC or CC) of the IL-6 gene variation, they might experience accelerated cognitive decline due to higher IL-6 levels. This is because the 'C' allele is associated with increased production of IL-6. This increased IL-6 can contribute to a pro-inflammatory environment within the brain. This inflammation could then potentially accelerate cognitive decline in older adults who already have some degree of cognitive impairment.

Who did the study focus on and what were the key findings regarding the IL-6 gene?

The study focused on older adults with existing cognitive impairment, but not dementia. The study found that those with the 'C' allele (GC or CC) of the IL-6 gene were more likely to experience a decline in their overall cognitive scores over a one-year period. The implication is that this genetic variation may contribute to cognitive decline by influencing IL-6 production, and subsequently, brain inflammation, in vulnerable individuals.

What is the take-away from this research, and how can this information be applied practically?

While you cannot change your genes, understanding the link between the IL-6 gene variation and cognitive decline can still be helpful. It emphasizes the importance of managing other factors that influence brain health, such as lifestyle, diet, and other genes. Further research could identify lifestyle interventions that help to reduce inflammation and potentially mitigate the impact of this specific gene variation on cognitive function.