Relationship between serum beta-2-microglobulin and cardiovascular risk factors

Abstract

OBJECTIVE: Serum beta-2-microglobulin (B2M) level reflects cellular turnover (especially lymphocytes) and renal tubular function. We previously reported its association with cardiovascular and all-cause mortality. We sought to explain this association in terms of cardiometabolic risk factors. METHODS: Data on 6474 participants (3114 men, 3360 women; mean age ± standard deviation, 44.7 ± 17.2 years) of the Third National Health and Nutrition Examination Survey were analysed using analysis of covariance. The relationship of B2M with age, body mass index (BMI), blood pressure, glycaemia, lipids, inflammation, and liver and renal functions were studied. Where appropriate, data were log-transformed. RESULTS: Serum B2M level was 1.92 ± 0.66 and 1.92 ± 0.77 mg/L in men and women, respectively (P>0.05). It correlated with age (r=0.57), BMI (r=0.15), systolic blood pressure (r=0.38), A1C (r=0.21), triglycerides (r=0.25), high-density lipoprotein (HDL; r=-0.14), aspartate aminotransferase (AST; r=0.18), alkaline phosphatase (ALP; r=0.29), C-reactive protein (r=0.28), and estimated glomerular filtration rate (eGFR; r= –0.66) [all P < 0.001]. In the fully adjusted model, serum B2M remained positively associated with systolic blood pressure (β=0.11; 95% confidence interval [CI], 0.04-0.18), AST (β=0.14; 95% CI, 0.10-0.18), ALP (β=0.10; 95% CI, 0.07-0.13), and CRP (β=0.05; 95% CI, 0.04-0.07), and negatively associated with HDL (β= –0.11; 95% CI, -0.07 to -0.15) and eGFR (β= –0.65; 95% CI, -0.60 to -0.69) [all P < 0.001]. CONCLUSIONS: The association of serum B2M level with Framingham risk factors as well as other risk factors of cardiovascular disease helps to explain why it is a good predictor of cardiovascular risk and mortality. This readily available blood test may be useful to identify high-risk patients and prompt the search for reversible causes.