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

Physical performance (PP) is an important component of health and well-being in older adults, often characterized by age-related decline. Inflammatory biomarkers, such as high sensitive C-reactive protein (hs-CRP), CRP, interleukin-6 (IL-6), interleukin-10 (IL-10), tumor necrosis factor-alpha (TNFα), that are commonly elevated as a result of low-grade systemic inflammation have been associated with a decline in physical functioning. Therefore, we systematically searched the articles investigating the relationship between these specific inflammation biomarkers and PP in community-dwelling older adults. Following PRISMA guidelines, a systematic search was conducted across the CINAHL, Cochrane, Medline (via EBSCOhost), PubMed, and Eric databases. Studies included adults aged ≥ 60 that measured CRP, hs-CRP, IL-6, IL-10, TNFα, and their association with physical performance gait speed (normal and fast pace), Short Physical Performance Battery (SPPB), timed up and go (TUG), chair stand (CST), and 6-minutes walking tests (6MWT). Only cross-sectional studies met the eligibility criteria and were included in the final review. Twenty studies were included in the final review, out of which six studies were classified as having very good quality, twelve with good quality, and two with satisfactory quality (assessed by an adapted Newcastle-Ottawa scale for cross-sectional studies). The majority of studies (85%) reported a statistically significant association between higher inflammation levels and poorer PP. Gait speed (normal pace) and SPPB were the most frequently assessed parameters, whereas IL-6, TNFα, and CRP were the most investigated inflammation biomarkers. CRP and hs-CRP were consistently linked with poorer PP in 85.7%, and 100% of studies respectively, while IL-6 showed positive associations in 53.8% of the studies. Findings suggest that hs-CRP and CRP biomarkers are associated with physical performance decline in older adults. Future research including a broader range of inflammation biomarkers should provide insights and understanding of mechanisms linking inflammation and physical decline.