Objective: We aimed to determine whether blood test values correlate with bone mineral density by body part. Participants and Methods: We included data on 78 forearms of 78 women, aged 50 or older, treated for distal radius fracture at our hospital from October 2007 to October 2012. All underwent DXA (dual-energy x-ray absorptiometry) scan of the second to fourth lumbar vertebrae, femoral neck, and forearm bone (divided into 3 parts: ultra-distal [UD], mid-distal [MD], and proximal shaft [shaft]). The following blood test values were determined: ALB (albumin), A/G (albumin/globulin) ratio, AST (aspartame aminotransferase), ALT (alanin aminotransferase), LDH (lactate dehydrogenase), ALP (alkaline phosphatase), GTP (gamma-glutamyl transferase), Ca (calcium), P (phosphorus), BUN (blood urea nitrogen), Crea (creatinine), eGFR (estimated glomerular filtration rate), WBC (white blood cell), Hb (hemoglobin), Hct (hematocrit), and PT-INR (international normalized ratio of prothrombin time). Statistical Analysis: Using Pearson product-moment correlation coefficients, we analyzed the DXA scan results (lumbar vertebrae, femur, and 3 forearm parts) for correlations with age, height, weight, body mass index (BMI), and blood test values. Results: ALB, A/G ratio, LDH, Hb, and PT-INR correlated positively with bone mineral densities of the forearm (UD, MD, and shaft) and femur (neck), but not with those of the lumbar vertebrae. TP (total protein), AST, ALT, γGTP (γ-Glutamyltranspeptidase), P, BUN, Crea, eGFR, WBC, Hb, and Hct did not correlate with any bone mineral density values. Discussion: The A/G ratio had a stronger correlation with the bone mineral density of the proximal shaft (0.39), which has a high percentage of cortical bone than with those of MD (0.38) and UD (0.26). The A/G ratio also correlated with femoral neck bone mineral density (0.23), but not with those of the lumbar vertebrae. Our results thus suggest a correlation between cortical bone amount and albumin metabolism. Conclusions: Our statistical analyses identified correlations between blood test values and bone mineral density by body part in middle-aged and elderly females with distal radius fracture. Serum albumin and the A/G ratio correlated positively with forearm and femoral neck bone mineral densities, but not with lumbar vertebrae bone mineral densities. From the resultant value, albumin 3.3g/dL or A/G ratio 0.96 is equivalent to −2.5 SD in DXA. Serum albumin and AJG ratio can be a surrogate marker for screening osteoporosis.
