Background: Serum albumin is affected by both nutritional status and inflammation. It is, therefore, thought to be highly linked with pathogenesis of vascular dysfunction.
Methods: Cross-sectional data from 2091 individuals aged 23-87, who underwent a general health examination, were analyzed. First, we investigated the association between serum albumin level and vascular functions, as assessed by brachial-ankle pulse-wave velocity (PWV). Then, we evaluated the prevalence of hyperglycemia (fasting blood sugar >or=100mg/dl), metabolic syndrome as determined by NCEP criteria, and inflammation (CRP >or=0.4mg/dl), across tertiles of albumin levels.
Results: In a multivariate regression model, a U-shaped relationship between serum albumin and PWV was statistically significant when albumin level was treated as a continuous variable in g/dl and centered at 4.4g/dl (quadratic term P-value=0.006). The highest tertile of albumin level (4.6-5.4g/dl) was associated with increased odds ratios for hyperglycemia of 1.35 (1.07-1.70) compared to the middle tertile (4.4-4.5g/dl), whereas the lowest tertile (3.3-4.3g/dl) was associated with reduced odds ratios for hyperglycemia of 0.80 (0.65-0.99). The highest tertile was also associated with increased odds ratios for metabolic syndrome of 1.30 (0.96-1.76) compared to the middle tertile, whereas the lowest tertile was associated with reduced odds ratios of 0.70 (0.51-0.95). Furthermore, the lowest tertile was associated with increased prevalence of inflammation with an adjusted odds ratio of 1.85 (1.15-2.97).
Conclusions: The current results demonstrate that extremes of serum albumin levels are linked to vascular dysfunction among healthy individuals. Furthermore, serum albumin is paradoxically linked to vascular disease under conditions both of overnutrition and of malnutrition and inflammation complex.