Association of hemoglobin level with fracture: a nationwide cohort study

Abstract

Introduction: The association between hemoglobin (Hb) level including anemia and fracture has not been studied thoroughly.

Materials and methods: 197, 187 adults ≥ 50 years from the National Health Insurance Service of Korea were studied. Hb was determined during health screening examinations in 2004 or 2005. From 1 January 2006, participants were followed up for fracture until 31 December 2013. Hb levels (g/dL) were categorized into five groups, with normal hemoglobin levels subdivided into three groups (low normal, normal, and high normal Hb): < 13, ≥ 13 to < 14, ≥ 14 to < 16, ≥ 16 to < 17, 17 for men and < 12, ≥ 12 to < 13, ≥ 13 to < 14, ≥ 14 to < 16, ≥ 16 for women. Anemia was defined as Hb < 13 g/dL and < 12 g/dL for men and women, respectively. Cox proportional hazards regression was used to determine the adjusted hazard ratios (aHRs) and 95% confidence intervals (CIs) for fracture according to Hb.

Results: Compared to individuals with normal Hb, those with anemia and low normal Hb were associated with significantly increased risk of fracture. In women, those with anemia had a higher risk for any (aHR 1.11, 95% CI 1.05-1.17), hip (aHR 1.27, 95% CI 1.01-1.59), and radius fracture (aHR 1.15, 95% CI 1.05-1.25). In men, those with anemia had a higher risk for any (aHR 1.37, 95% CI 1.23-1.51), vertebral (aHR 1.33, 95% CI 1.15-1.53), and hip fracture (aHR 1.64, 95% CI 1.30-2.08). This risk-enhancing association was preserved among various subgroups.

Conclusion: Among adults ≥ 50 years, anemia and low normal Hb are risk factors for fracture.

Keywords: Anemia; Fracture; Hemoglobin level; Osteoporosis.