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

Abstract

BACKGROUND AND PURPOSE: 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 6,474 participants (3114 men, 3360 women; age, mean±SD, 44.7±17.2 yrs) of the Third National Health and Nutrition Examination Survey were analyzed using ANCOVA. The relationship of B2M with age, BMI, blood pressure, glycemia, lipids, inflammation, liver and renal function were studied. Where appropriate, data were log-transformed. RESULTS: Serum B2M level (mean±SE) 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), HDL (r=−0.14), AST (r=0.18), ALP (r=0.29), CRP (r=0.28) and eGFR (r=−0.66) (all p-values<0.001). In the fully adjusted model, serum B2M remained positively associated with systolic blood pressure (β=0.11, 95% CI: 0.04 to 0.18); AST (β=0.14, 95% CI: 0.10 to 0.18), ALP (β=0.10, 95% CI: 0.07 to 0.13), and CRP (β=0.05, 95% CI: 0.04 to 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 pvalues< 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.