Measurement of 25-hydroxyvitamin D serum levels and its seasonal variations in healthy young people Determinación de los niveles séricos de 25-hidroxivitamina D y sus variaciones estacionales en una población normal joven

Abstract

Background: 25-hydroxyvitamin D has a longer half life and its serum levels have less daily variations than calcitriol. Thus, its measurement is a better indicator of vitamin D status. Aim: To measure 25-hydroxyvitamin D levels in normal subjects during summer and winter. Patients and methods: Vitamin D was measured using a competitive protein binding radioassay in 61 subjects (27 male) aged 21 to 57 years old, during July and August (winter) and February and March of the next year (summer). Results: 25-hydroxyvitamin levels were 28.8 ± 1.5 and 30.9 ± 2.3 ng/mt during winter and summer respectively. No differences were found between men and women. Ninety five percent confidence levels were between 13 and 50 ng/ml. Levels in one patient with malabsorption were 9.3 ng/ml, in 2 patients with hypophosphemic osteomalacia were 2.1 and 9.3 ng/ml, in 12 patients with alcoholic cirrhosis were 16.4 ± 1.3 ng/ml, in 4 patients with primary osteoporosis were 23.3 ± 0.7 and in three patients receivi