Prevalence and Predictors of Vitamin D Insufficiency in Adolescents Living at an Intermediate Altitude.

Abstract

Although vitamin D insufficiency is a very common health problem in the world, its prevalence and predictors in adolescents are controversial. We planned to evaluate prevalence and predictors of vitamin D insufficiency in adolescents living at an intermediate altitude. We also want to give optimal serum 25(OH) vitamin D levels in relation to serum PTH levels. The study population comprised 343 primary and high school children living in Erzurum city centre whose ages ranged between 13 to 17 years. These children were selected using stratified random sampling in the spring (April-May), and were invited to our department for participation in this research study. Of 343 children, 246 could be evaluated again in the autumn (September-October). Subjects with vitamin D level < 10 ng/ml were considered as being vitamin D deficient, and with 10 - 20 ng/ml as being vitamin D insufficient and those with vitamin D level > 20 ng/ml are considered to have adequate. In spring, vitamin D deficiency was detected in 17.7% of the subjects while vitamin D insufficiency was detected in 72%. At the end of summer these rates were 1.6 % and 41.1 % respectively. Serum 25 (OH) vitamin D levels at which plasma PTH concentrations begin to form a plateau is 22 ng/mL. Values below estimated lower normal level (22 ng/mL) were detected in 94.2 % of subjects. We believe that vitamin D prophylaxis could be given to all adolescents as well as for the regulation of lifestyles. Our results will increase awareness for vitamin D deficiency and insufficiency in adolescents and inform future public health preventative strategies.