As populations age, scientists are looking more closely at a hidden biological process that may help explain why some older adults remain mobile and independent while others experience a rapid decline in strength, balance, and endurance. A systematic review by A. Boshnjaku, R. Obërtinca, M. Hoxha, and colleagues examines whether five inflammation-related biomarkers—CRP, high-sensitivity CRP, interleukin-6, interleukin-10, and tumor necrosis factor-alpha—are linked to physical performance in older adults living in the community. Published in BMC Geriatrics, the review focuses on a question with major implications for healthy aging: can signals circulating in the blood reveal who is at greater risk of losing physical function?

The study centers on chronic, low-grade inflammation, a biological condition often associated with aging and commonly described as “inflammaging.” Unlike the intense inflammation triggered by an infection or injury, inflammaging can persist quietly over years. It may be influenced by immune-system changes, excess body fat, physical inactivity, chronic disease, and cellular stress. Although inflammation is essential for repairing tissue and fighting pathogens, prolonged activation can affect muscle metabolism, blood-vessel function, nervous-system signaling, and energy production. These changes could, in theory, make everyday movements such as walking, rising from a chair, or climbing stairs increasingly difficult.

C-reactive protein, or CRP, is one of the most widely used indicators of systemic inflammation. It is produced primarily by the liver in response to inflammatory signals, especially interleukin-6. Standard CRP testing is useful for detecting relatively pronounced inflammatory activity, while high-sensitivity CRP, known as hs-CRP, can measure much lower concentrations. That distinction matters in research on older adults, where subtle inflammatory differences may exist even when there is no obvious acute illness. However, neither CRP nor hs-CRP identifies a single disease or proves that inflammation itself caused a decline in physical ability.

The review also considers three signaling proteins known as cytokines. Interleukin-6, or IL-6, can promote inflammation but also participates in muscle adaptation and energy regulation, making its effects highly dependent on timing, tissue, and physiological context. Tumor necrosis factor-alpha, or TNF-α, is a potent inflammatory mediator that can influence muscle protein breakdown and interfere with insulin signaling. Interleukin-10, or IL-10, generally acts as an anti-inflammatory regulator, helping restrain excessive immune activation. Examining these markers together offers a more nuanced picture than relying on a single laboratory value.

Physical performance is a crucial measure of aging because it reflects how effectively multiple systems work together. Muscle strength alone does not determine whether a person can remain independent. Walking speed, repeated chair stands, balance, grip strength, endurance, and composite tests such as the Short Physical Performance Battery can reveal the combined effects of the muscular, cardiovascular, neurological, and skeletal systems. For people living outside hospitals and care facilities, these measures may also provide a practical snapshot of resilience in everyday life. A small difference in performance can translate into a major difference in fall risk, mobility, and the ability to manage daily activities.

By bringing together evidence from studies of community-dwelling older adults, the authors address an important gap between laboratory research and real-world aging. Older people living independently are not a uniform group: some have multiple chronic conditions, while others remain highly active; some take anti-inflammatory medications, and others do not. Diet, smoking, obesity, socioeconomic conditions, sleep, recent infections, and exercise can all alter cytokine levels and physical performance. A systematic review can help determine whether associations between biomarkers and function appear consistently across this complex population or whether they vary substantially from one study to another.

The review’s importance lies not only in asking whether inflammatory markers are associated with poorer performance, but also in highlighting the limitations of interpreting such relationships. A high biomarker level may be a consequence of frailty, reduced activity, obesity, or an undiagnosed illness rather than the original cause of decline. Conversely, a single blood sample may fail to capture fluctuations in inflammation over time. Differences in laboratory methods, cutoff values, participant health, medication use, and performance tests can make studies difficult to compare. These issues are central when translating population-level associations into decisions about an individual patient.

The findings may ultimately support a broader approach to healthy aging in which inflammation is considered alongside strength, nutrition, cardiovascular health, cognition, and social environment. The biomarkers discussed in the review are not presented as standalone tests that can predict the future with certainty. Instead, they may help researchers understand why physical function changes and identify biological pathways that could be targeted through exercise, weight management, treatment of chronic disease, or other interventions. The study also underscores the need for longitudinal research capable of separating cause from consequence and for standardized testing that can connect laboratory signals with meaningful improvements in daily life.

For now, the review places a spotlight on the immune system as a possible contributor to the physical changes associated with later life. Its focus on CRP, hs-CRP, IL-6, IL-10, and TNF-α reflects the growing recognition that aging is not simply the result of muscles becoming weaker, but of interconnected changes across the body. Understanding how these inflammatory signals relate to mobility could help scientists develop more precise strategies for preserving independence—while reminding clinicians and the public that a blood test is most informative when interpreted together with a person’s functional ability, medical history, and lived environment.

Subject of Research: The relationship between inflammatory biomarkers and physical performance in community-dwelling older adults.

Article Title: What is the impact of CRP, hs-CRP, IL-6, IL-10, and TNFα in physical performance in community-dwelling older adults: a systematic review.

Article References: Boshnjaku, A., Obërtinca, R., Hoxha, M. et al. What is the impact of CRP, hs-CRP, IL-6, IL-10, and TNFα in physical performance in community-dwelling older adults: a systematic review. BMC Geriatrics (2026). https://doi.org/10.1186/s12877-026-08080-8

Image Credits: AI Generated

DOI: 10.1186/s12877-026-08080-8

Keywords: aging, older adults, inflammation, CRP, hs-CRP, IL-6, IL-10, TNF-α, physical performance, inflammaging, systematic review

Tags: biomarkers predicting functional declinechronic low-grade inflammation in elderlycommunity-dwelling older adultsimmune system changes with ageinflammaging and mobility declineinflammation’s impact on balance and strengthinflammatory biomarkersmuscle metabolism and inflammationphysical performance and agingrole of CRP and cytokines in agingsystemic inflammation and aging-related disability