Anemia and the risk of non-vertebral fractures: the Tromsø Study.
In this longitudinal study of 5,286 persons, men with anemia had a 2.15 higher risk of non-vertebral fractures than men with high hemoglobin levels. Women with anemia had no increased fracture risk. Low hemoglobin levels are associated with several risk factors for fractures such as low physical function, impaired cognition, and low bone mass. The aim of this population-based, prospective study was to examine whether anemia predicts non-vertebral fractures. A total of 5,286 inhabitants from the municipality of Tromsø, Norway (2,511 men and 2,775 women), 55-74 years old at baseline, were followed for mean 8.3 years. Measurements of hemoglobin, mean corpuscular volume, height, weight, blood pressure, blood lipids, serum creatinine, and bone mineral density and questionnaire information concerning smoking and drinking habits, physical activity, prevalent diseases, and use of medication was collected before start of follow-up. Non-vertebral fractures were registered during follow-up. A total of 235 men and 641 women sustained a new non-vertebral fracture. One SD lower value of hemoglobin was associated with a 1.27 higher risk of fracture in men (p < 0.001, after multiple adjustments) and 1.08 (p = 0.07) in women. Men with anemia (hemoglobin levels <13 g/dL) had a 2.15 higher risk of non-vertebral fractures than men with high levels (15.2-18.8, g/dL) whereas women with anemia (hemoglobin levels <12 g/dL) had no increased fracture risk. Anemia is associated with non-vertebral fractures in men but not in women.