Hypoalbuminemia and Osteoporosis: Reappraisal of a Controversy.

CONTEXT Human studies have reported conflicting results on the association of hypoalbuminemia with osteoporosis. OBJECTIVE The aim of the study is to test the independent association between hypoalbuminemia and osteoporosis. DESIGN This is a cross-sectional observation. SETTING AND PARTICIPANTS Patients are the outpatient consecutive individuals with available clinical, laboratory, and densitometry data from 2001 to 2013 in our tertiary care academic medical center. EXPOSURE Exposure is hypoalbuminemia defined as serum albumin less than 3.5 g/dL. MAIN OUTCOME MEASURE Osteoporosis is defined as bone mineral density of 2.5 SD or less below the mean peak bone mass of young, healthy adults. RESULTS Overall, 21 121 patients were included. Mean of age was 61 years (SD 14). There were 4244 males (20.1%) and 1614 patients of African-American ethnicity (7.6%). There was a graded decrease in rate of osteoporosis from 28.0% (n = 33) at albumin of 3 g/dL or less to 9.3% (n = 1548) at albumin greater than 4 g/dL (P < .001) at the femoral neck and from 20.3% (n = 24) to 6.1% (n = 1011) at the total hip (P < .001). In a fully adjusted model, the odds of osteoporosis at albumin of 3 g/dL or less was 3.31-fold (95% confidence interval [CI] 2.08-5.28, P < .001) at the femoral neck, 2.98-fold (95% CI 1.76-5.01, P < .001) at the total hip, and 2.18-fold (95% CI 1.43-3.31, P < .001) at the lumbar spine as compared with albumin greater than 4 mg/dL. A similar independent association was identified with a longer-observed duration of hypoalbuminemia. CONCLUSION In a large population, we report an independent association of osteoporosis with lower levels of serum albumin and a longer-observed duration of hypoalbuminemia.