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1. Introduction
Vitamin D is a preprohormone known to play a key role in the metabolism of phosphates and calcium. Its main source is the synthesis by ultraviolet (UV) radiation in the skin [1, 2]. The intensity of UV rays will depend on the height of the sun, latitude, cloudiness, altitude, ozone layer, and soil reflection [3].
Ecuador is located on the equator at a latitude of −0.95, with two seasons: winter (January–April) and summer (May–December). The solar radiation index is 10-11 UV, which is considered as very high radiation levels; however, the general population takes measures to avoid sun exposure which results in insufficient levels of vitamin D. The objective of this study was to determine vitamin D status by measuring serum calcidiol (25 (OH)-D) in an Ecuadorian population that had attended a first consultation at a Rheumatology Center.
2. Materials and Methods
Retrospective study of Ecuadorian subjects from the city of Guayaquil, Ecuador, who had an initial study of serum 25 (OH)-D, as the indicator of vitamin D status, from 2015 to 2016.
3. Determination of Vitamin D
The 25 (OH)-D serum levels of the patients had been measured in the same laboratory. Samples were analyzed by the chemiluminescence method with an Advia Centaur® assay system. Serum 25 (OH)-D levels are not standardized for each population; however, the following (1.4–6) are considered:
(i)
Ideal: 30–40 ng/dL
(ii)
Deficiency: 30–20 ng/dL
(iii)
Insufficiency: 20–10 ng/dL
(iv)
Severe insufficiency: <10 ng/dL.
The patients were from the city of Guayaquil located in Guayas province, at six meters above sea level and at a latitude of −0.95, with a solar exposure index of 10-11 UV.
3.1. Statistical Analysis
The data was analyzed using the statistical program SPSS v 22, with