This issue of “Progress in Medicine” focuses on a selection of the most common metabolic bone diseases: osteoporosis in adults, nutritional rickets and osteogenesis imperfecta in children and the significant role of vitamin D on calcium and bone homeostasis and on its pleiotropic action. We present five original articles, one case report, twelve review articles and expert recommendations that focus on current information.

In their article on vitamin D status and disease activity in patients with rheumatoid arthritis (RA), Povoroznyuk et al. revealed that vitamin D deficiency should be considered an important predictor of the high RA activity.

Łupińska and Chlebna-Sokół focused their research on the evaluation of the prevalence of vitamin D deficiency in school children with excess body weight. The authors revealed a negative relationship between fat mass, body weight and serum 25(OH)D concentration. This result confirms the theory that obesity is a possible risk factor for vitamin D deficiency and demonstrates how important it is to adhere to the existing recommendations for vitamin D supplementation with this group.

Rusińska et al. compared the clinical symptoms of various types of osteogenesis imperfecta (OI) in patients supervised by their Department. They concluded that OI is a heterogeneous group of skeletal disorders associated with increased predisposition to fractures, and characterised by significant variation of symptoms in individual types of the disease. The authors stress that a clear diagnosis and prognosis can be difficult in some patients, due to the “overlapping” of symptoms in some types of OI (I and IV, II and III, III and IV) and the modifying effect of implemented treatment.

Kupisz-Urbańska et al. evaluated vitamin D supplementation in elderly nursing home residents and concluded that, among all the subjects, three months of vitamin D supplementation was sufficient to achieve a vitamin D serum suboptimal value.

Wójcik et al. compared the methods for serum determination of 25(OH)D (automatic CLIA on IDS-iSYS and LIAISON analyzers) and 1,25(OH)₂D (semi-automatic CLIA on IDS-iSYS analyzer and manual RIA) in pediatric and DEQAS samples. They found a high precision of serum 25(OH)D and 1,25(OH)₂D determination using CLIA methods on the IDS-iSYS platform. The comparison of these methods with the methods routinely used in the Department of Biochemistry, Radioimmunology and Experimental Medicine make it possible for their use in clinical practice in pediatric hospitals while maintaining the highest diagnostic standards.

Jakubowska-Pietkiewicz et al. presented the diagnosis and treatment, including intensive medical and hospice care, in a 3 year old boy diagnosed with type II OI. The evolution in both the diagnosis and therapy, as well as the necessity for multidisciplinary cooperation, which changes clinical course and prognosis for lethal IO, were highlighted.

Płudowski et al. in a review article entitled „Best practices for the management of vitamin D deficiency” explain that because of growing evidence of vitamin D related pleiotropic effects, an update of supplementation guidelines is warranted to ensure its optimum supply and health benefits. They stress that vitamin D supplementation guidelines should be adopted regionally or nationally, but not as a global recomendation, as more optimal. From practical perspective, the choice of the most appropriate recommendations will depend on many factors both clinically and environmentaly.