The intervention of vitamin D in our immune system activity led to the study of this hormone’s effect on SARS-CoV-2 infection from the start of the pandemic. Published studies have already been analyzed in other chapters of this special edition. Some societies and scientific and health institutions have considered this topic, and based on these reflections, offer recommendations to the health community. In this chapter, we present a brief overview.

Seven years have passed since the most recent version of the Osteoporosis Guidelines of the Spanish Society for Bone Research and Mineral Metabolism (SEIOMM) was drawn up, using the standard methodology of evidence‐based medicine [1]. This update incorporates information released since then. The full text is available in the Guide.

2. Methods
A group of experts (see annexe) reviewed each section to incorporate the new findings published in recent years. The new text was disseminated to other interested entities (including SEIOMM partners, patient associations, the Spanish Agency for Medicines and Health Products, and pharmaceutical industries) to provide input to the document, which was subsequently analysed by the group of experts. Osteoporosis in postmenopausal women was analysed first, followed by osteoporosis in men and glucocorticoid‐induced osteoporosis.

Seven years have passed since the publication of the previous version of the Osteoporosis Guidelines of the Spanish Society for Bone Research and Mineral Metabolism (SEIOMM) that was created in accordance with the standard methodology of evidence‐based medicine [1]. This update incorporates the most essential information that has appeared since the publication of the previous version, with particular reference to new diagnostic procedures and therapeutic options. Novel diagnostic modalities discussed in these guidelines include the Trabecular Bone Score (TBS) and the detection of vertebral fractures by densitometry. Among the therapeutic options, we discuss the use of novel anabolic drugs (abaloparatide and romosozumab). Studies that compare the efficacy of various drug regimens for the treatment of severe osteoporosis are also considered. Likewise, the guidelines for action after the withdrawal of antiresorptive drugs and other sequential and combined treatment schemes are assessed.

Diabetes mellitus (DM2) and osteoporosis are increasing prevalence diseases due to the aging of the population, and gender, genetic and environmental factors, such as an unbalanced diet, obesity and a sedentary life. DM2 increased alarmingly in 2014, affecting more than 420 million people worldwide [1]. Patients with DM2 present a higher risk of falls and increased prevalence and incidence of fragility fractures have been observed in these patients [2-5], causing significant mortality, morbidity and increased healthcare costs.
DM2 affects bone homeostasis [6,7], and is associated with a higher risk of fractures [8], despite the fact that patients exhibit higher bone mineral density (BMD) [4,9-12]. Furthermore, reduced circulating levels of bone turnover markers have been observed in DM2 [13], which should influence the high fracture risk in patients with DM2.