In the linked systematic review (doi:10.1136/bmj.c3691), Bolland and colleagues assessed whether calcium supplements increase the risk of cardiovascular events in people with, or at risk of, osteoporosis.1 They found that calcium supplements increased the risk of myocardial infarction (hazard ratio 1.31, 95% confidence interval 1.02 to 1.67), but they found no significant difference in the risk of stroke, death, or the composite end point of myocardial infarction, stroke, or sudden death.

The effort spent on detecting and treating osteoporosis is only worthwhile if it translates into a health benefit for patients. The most common argument for detecting and treating osteoporosis is a reduction in bone fractures that are either subtle and progressive (for example, those that cause loss of vertebral height) or overt (for example, fractures of the hip and wrist). Bone mineral density, which is often used as a measure of treatment success, is a surrogate measure for real clinical benefit.

Surrogate measures may be useful in pilot studies but become problematic when they become the goal of treatment. 2 3 Bone fractures in older people are an important cause of disability, and more than 20% of patients will die within one year of a low trauma hip …