Chronic use of low-dose aspirin is not associated with lower bone mineral density in the general population

Background Low-dose aspirin is the cornerstone of secondary prevention of cardiovascular disease. Previous studies suggested that the use of aspirin is associated with an increased fracture risk. However, there is uncertainty whether this is due to an effect of aspirin on bone mineral density (BMD). Methods Between 2008 and 2012, information on medication use and dual X-ray absorptiometry measured vertebral and femoral BMD of 916 participants was collected in the Netherland Epidemiology of Obesity study. The cross-sectional association between chronic low-dose aspirin use and BMD was estimated using linear regression, controlling for demography, body composition, comorbidity and other medication use which could affect BMD. A subgroup analysis in postmenopausal women (n=329) was conducted. Results After full adjustment, there was no difference between aspirin users and non-users for vertebral BMD (adjusted mean difference: 0.036 (95% CI −0.027 to 0.100) g/cm2) and femoral BMD (adjusted mean difference: 0.001 (−0.067 to 0.069) g/cm2). Also in the subgroup of postmenopausal women, aspirin use was not associated with lower vertebral (adjusted mean difference: 0.069 (−0.046 to 0.184) g/cm2) or femoral BMD (adjusted mean difference: −0.055 (−0.139;0.029) g/cm2). Conclusion Chronic use of low-dose aspirin is not associated with lower BMD in the general population. The increased risk of fractures observed in aspirin users in previous studies is therefore more likely to be the result of common causes of aspirin use and fractures, but not of direct effects of aspirin on BMD.