The association between albumin and C-reactive protein in older adults

Albumin had been found to be a marker of inflammation. The purpose of our study was to investigate the relationship between albumin and C-reactive protein (CRP) in 3579 participants aged 60 to 80 years from the National Health and Nutrition Examination Survey (NHANES). In order to evaluate the association between albumin and CRP, We downloaded the analyzed data (2015-2018) from the NHANES in the United States, and the age of study population was limited to 60 to 80 years (n = 4051). After exclusion of subjects with missing albumin (n = 456) and CRP (n = 16) data, 3579 subjects aged 60 to 80 years were reserved for a cross-sectional study. All measures were calculated accounting for NHANES sample weights. We used the weighted χ2 test for categorical variables and the weighted linear regression model for continuous variables to calculate the difference among each group. The subgroup analysis was evaluated through stratified multivariable linear regression models. Fitting smooth curves and generalized additive models were also carried out. We found albumin negatively correlated with CRP after adjusting for other confounders in model 3 (β = -0.37, 95% CI: -0.45, -0.28, P < .0001). After converting albumin from a continuous variable to a categorical variable (quartiles), albumin level was also negatively associated with serum CRP in all groups (P for trend < .001 for each). In the subgroup analysis stratified by gender, race/ethnicity, smoking, high blood pressure, the negative correlation of albumin with CRP was remained. We also found that the level of CRP further decreased in other race (OR: -0.72, 95% CI: -0.96, -0.47 P < .0001) and participants with smoking (OR: -0.61, 95% CI: -0.86, -0.36 P < .0001). Our findings revealed that albumin levels was negatively associated with CRP levels among in USA elderly. Besides, CRP level decreased faster with increasing albumin level in other race and participants with smoking. Considering this association, hypoalbuminemia could provide a potential predictive biomarker for inflammation. Therefore, studying the relationship between albumin and CRP can provide a screening tool for inflammation to guide therapeutic intervention and avoid excessive correction of patients with inflammation.