*5.2.3 VD pleiotropy after KT: infection*

Infection is a major cause for death after KT. Several recent reports established negative correlation between VD status and infection risk, especially for cytomegalovirus and BK virus infections in KTRs [91, 92]. However, our observational study showed no association between VD status and prevalence of urinary tract infections after KT [93]. Furthermore, the VITA-D study did not establish positive effect of cholecalciferol supplementation on infection risk [88]. A probable explanation for the discrepancies in the studies are the different types of infection evaluated (e.g. in the VITA-D study the total infection risk was assessed). Probably, a more specific

approach should be chosen and the infection risk for specific etiological agent and its association to VD should be analyzed.

### *5.2.4 VD pleiotropy after KT: malignancies*

Despite the anti-neoplastic properties of VD *in vitro* and in animal models, the evidence for anti-malignancy effect of VD in CKD patients and KTRs is insufficient. Observational studies report conflicting results for the association between posttransplant malignancies and VD status [86]. A recent study in our transplant center showed that VD-deficient KTRs had higher prevalence of non-cutaneous cancers [94]. A single center study established beneficial effect from active VD supplementation on post-transplant neoplasia rates [95]. The larger prospective, multicenter, double-blind, randomized, controlled study VITALE is currently being performed, which will evaluate the effect of cholecalciferol supplementation on malignancy risk after KT [96].
