Vitamin D deficiency and seasonal variation over the years in So Paulo, Brazil

Vitamin D deficiency and seasonal variation over the years in So Paulo, Brazil

Author Eloi, Marina Autor UNIFESP Google Scholar
Horvath, Daniela Vargas Autor UNIFESP Google Scholar
Szejnfeld, Vera Lucia Autor UNIFESP Google Scholar
Ortega, João Carlos Autor UNIFESP Google Scholar
Rocha, D. A. C. Google Scholar
Szejnfeld, Jacob Autor UNIFESP Google Scholar
Castro, Charlles Heldan de Moura Autor UNIFESP Google Scholar
Abstract Brazil is a tropical/subtropical geographic area with elevated ultraviolet (UV) radiation. We report very high prevalence of vitamin D deficiency in a large database of Brazilian subjects and show seasonal and reciprocal relationship between vitamin D and parathyroid hormone (PTH) over the years in this tropical area. We aim to examine the prevalence of vitamin D deficiency, characterize the temporal relationship between 25-hydroxyvitamin D levels (25(OH)D) and intact PTH (iPTH) according to seasons, and investigate potential associations between 25(OH)D levels and extra-skeletal outcomes in a Brazilian population. We retrospectively determined population weekly mean concentrations of unpaired 25(OH)D and iPTH using 39,004 laboratory results of Brazilian individuals of both genders aged 2 to 95 years. The 25(OH)D and iPTH distributions were normalized, and the means fit with a sinusoidal function. Potential associations between 25(OH)D serum levels and inflammatory markers, fasting glucose, HbA1c and Homeostasis Model Assessment index (HOMA) were examined. Of the samples, 33.9 % had 25(OH)D serum concentrations lower than 20 ng/mL, while the vast majority (70.7 %) were found to be vitamin D deficient or insufficient (< 30 ng/mL). Vitamin D deficiency was significantly higher during the winter as compared to the summer (38.4 % < 20 ng/mL and 75.5 % < 30 ng/mL versus 23.3 % < 20 ng/mL and 62.5 % < 30 ng/mL, respectively

p < 0.001). Seasonal variation was observed for both 25(OH)D and iPTH. 25(OH)D peaks occurred in March and troughs in September. iPTH levels showed an inverted pattern of peaks and troughs with a delay of 1 +/- 5 week. 25(OH)D was significantly associated with inflammatory markers but not with glucose homeostasis. A sinusoidal interrelationship has been detected between vitamin D and PTH in this tropical population. A large percentage of the individuals showed vitamin D deficiency. Public health strategies are needed to better understand and manage this very high and apparently contradictory prevalence of vitamin D deficiency.
Keywords 25(OH)D
Brazilian population
Glucose homeostasis
Vitamin D
xmlui.dri2xhtml.METS-1.0.item-coverage London
Language English
Date 2016
Published in Osteoporosis International. London, v. 27, n. 12, p. 3449-3456, 2016.
ISSN 0937-941X (Sherpa/Romeo, impact factor)
Publisher Springer London Ltd
Extent 3449-3456
Access rights Closed access
Type Article
Web of Science ID WOS:000388953700005

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