Decreasing hemoglobin (Hb) levels and the presence of anemia may lead to decreased cortical bone mineral density (BMD) and an increased risk for fracture among older women. Consideration of Hb levels may improve diagnosis and evaluation for osteoporosis, as well as evaluation for fracture risk, according to study results published in The Journal of Clinical Endocrinology & Metabolism (Oxford).
Further assessment was conducted to determine whether Hb levels contribute to the accuracy of predicting fracture risk when combined with a fracture risk assessment tool (FRAX®).
A prospective, population-based cohort study was conducted. Women aged from 75 to 80 years enrolled in the Sahlgrenska University Hospital Prospective Evaluation of Risk of Bone Fractures study who had complete data on Hb levels and imaging were included in the study cohort.
A total of 148 hip fractures (5.3%), 601 major osteoporotic fractures (MOF; 21.6%), and 734 fractures of any kind (26.4%) occurred during the median follow up period of 6.4 years. Additionally, 344 deaths (12.4%) occurred during this period.
Low levels of Hb and anemia were both associated with decreased BMD at the femoral neck and total hip, as well as decreased cortical BMD and increased porosity in the tibia. These findings suggested that the reduced bone strength among individuals with low Hb levels is primarily due to cortical bone issues.
Hemoglobin levels were found to have a positive correlation with age, height, weight, and albumin levels but a negative correlation with creatinine levels. Hemoglobin levels were also negatively correlated with 10-year probabilities for both hip fractures and major osteoporotic fracture (MOF), assessed with or without femoral neck BMD, according to FRAX® assessment.
Women with anemia were likely to have rheumatoid arthritis, secondary osteoporosis, and a history of falling within the past year.
Using models adjusted for age, height, weight, FRAX®-assessed clinical risk factors, and femoral neck BMD, anemia was associated with an increased risk for MOF, (hazard ratio [HR], 1.85; 95%CI, 1.43-2.41), hip fracture (HR, 1.75; 95% CI, 1.06-2.90) and fracture of any kind (HR, 1.80; 95% CI, 1.41-2.28), over a median follow-up time of 6.4 years.
Limitations of this study included its cross-sectional design, which relied on a single measurement of both Hb and BMD. Due to this single measurement, investigators were unable to determine causality or whether risk factors related to Hb levels can be reversed.
The study authors concluded, “Considering Hb levels may improve the clinical evaluation of patients with osteoporosis and assessment of fracture risk.”
Jaiswal R, Johansson H, Axelsson KF, et al. Hemoglobin levels improve fracture risk prediction in addition to FRAX® clinical risk factors and bone mineral density. J Clin Endocrinol Metab. Published online July 5, 2023. doi:10.1210/clinem/dgad399