Lixin Sun, Cuie Li, Bin-Bin Feng, Yong-Yong Liu, Ruo-Wei Ma, Yu-Xuan Zhang and Guo-Cui Wu* Pages 1 - 9 ( 9 )
Aim: Inflammation and nutritional status have significant roles in frailty. While albumin and the albumin-to-globulin ratio (AGR) are recognized as inflammatory and nutritional biomarkers, and globulin is associated with inflammation, their relationships with frailty remain underexplored. This study explored the relationships between albumin, globulin, AGR, and frailty among middle-aged and older adults, utilizing data from the National Health and Nutrition Examination Survey (NHANES) database.
Methods: The study was a cross-sectional study with participants aged ≥45 years from the 2013-2014 NHANES database. The frailty assessment was based on a 36-item index of frailty constructed in NHANES, excluding nutritional indicators. The relationships between albumin, globulin, AGR, and frailty were analyzed using weighted multivariate regression analyses, smooth curve fitting, two-segment linear regression models, subgroup analyses, and interaction tests.
Results: This study involved 1,506 middle-aged and older participants, with a frailty rate of 42.23%. Nonlinear relationships were identified between albumin, AGR, and frailty, while a linear relationship was observed between globulin and frailty. Two-segment linear regression models demonstrated that the inflection points for albumin and AGR were 3.90 and 1.91, respectively. On the left side of these inflection points, albumin and AGR were negatively associated with the prevalence of frailty. On the right side of these inflection points, albumin and AGR were not significantly associated with the prevalence of frailty.
Conclusion: This study reveals two threshold effects on frailty in middle-aged and older adults: albumin and AGR. Below specific thresholds, both are linked to reduced frailty risk, but above these levels, neither shows a significant association. Globulin, however, consistently correlates with increased frailty. These findings highlight nonlinear relationships between albumin, AGR, and frailty, suggesting that maintaining optimal levels of these biomarkers may help prevent frailty.
Albumin, AGR, frailty, globulin, middle-aged and older adults, NHANES.