**5. Conclusions**

A high prevalence of hypovitaminosis D was found in institutionalized elderly individuals living in a region with high ultraviolet radiation levels, and this was significantly associated with summer. These findings sugges<sup>t</sup> the probability of the presence of interfering vitamin D factors mediated by aging. In this scenario, aging conditions which increase the risk of vitamin D deficiency have to be taken into consideration. Furthermore, the institutionalization of elderly individuals needs to be carefully handled to create alternatives that mitigate aging-related health problems.

**Author Contributions:** Conceptualization, S.E.S.S., K.C.L., and L.F.C.P.; data curation, S.E.S.S., M.C.S., and J.R.T.A.; formal analysis, S.E.S.S. and K.C.L.; funding acquisition, K.C.L. and L.F.C.P.; investigation, S.E.S.S. and L.F.C.P.; methodology, S.E.S.S., M.C.S., J.R.T.A., K.C.M.S.-E., K.C.L., and L.F.C.P.; project administration, K.C.L. and L.F.C.P.; supervision, K.C.M.S.-E., K.C.L., and L.F.C.P.; validation, S.E.S.S., M.C.S., J.R.T.A., K.C.L., and L.F.C.P.; visualization, S.E.S.S.; writing—original draft, S.E.S.S. and L.F.C.P.; writing—review & editing, S.E.S.S., M.C.S., J.R.T.A., K.C.M.S.-E., K.C.L., and L.F.C.P.

**Funding:** This research was supported by the Research Support Foundation of Rio Grande do Norte (Fundação de Apoio à Pesquisa do Rio Grande do Norte—FAPERN) and the National Council for Scientific and Technological Development (Conselho Nacional de Desenvolvimento Científico e Tecnológico—CNPq, Brazil; gran<sup>t</sup> no 77228/2013). This study was also financed by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior—Brasil (CAPES)—Finance Code 001.

**Conflicts of Interest:** The authors declare no conflict of interest.
