Vitamin D and bone fracture mechanisms: what about the non-bone 'D'efense?

Osteoporosis is a public health concern because of its high prevalence and consequences in terms of morbidity, mortality and health care costs (1). This growing epidemic highlights the problem of the 'knowledge paradox': on one hand there is an increase in medical knowledge about osteoporotic fractures but, on the other hand, the amount of bone fractures keeps increasing (1-3). In this context, any strategy preventing the occurrence of bone fractures, such as vitamin D supplementation, is welcome. For instance, a very recent meta analysis from Bischoff-Ferarri et al. underlined the efficacy of oral supplemental vitamin D, regardless of any additional calcium supplementation, in non-vertebral fractures prevention among more than 42,000 adults aged 65 years and older (2).