title: Hypovitaminosis d: are medical students at risk?
abstract: BACKGROUND
  Vitamin D deficiency is a pandemic problem mostly diagnosed in elderly. Few studies are available exclusively done on the topic among young adults. Specific professions such as medical students may have higher risk for developing hypovitaminosis D. We aimed to assess the vitamin D status in medical students of Iran University of Medical Sciences; and to define a cut-off point for 25-hydroxyvitamin-D (25(OH)D) level based on secondary hyperparathyroidism.
  
  
  METHODS
  This was a cross-sectional study on 100 medical students conducted during October 2012. Serum 25(OH)D, intact parathyroid hormone (iPTH), and calcium were measured. Age, sex, body mass index, daily dietary fish and egg consumption, sun exposure, and sunscreen usage were recorded. The association between serum 25(OH)D and iPTH was assessed. Receiver operating characteristics curve analysis was performed.
  
  
  RESULTS
  25-hydroxyvitamin-D level was <30 ng/ml in 99% of all participants, and <20 ng/ml in 77%. Mean serum 25(OH)D level was 16.8 ± 4.7 ng/ml. iPTH level in the group with 25(OH)D level of <10 ng/ml was significantly higher than in those with serum 25(OH)D level of 10 to <20 ng/ml and 20 to <30 ng/ml (109 ± 47 pg/ml, 47 ± 27 pg/ml and 46 ± 19 pg/ml, respectively; P = 0.0001). There was a significant linear inverse correlation between serum iPTH and 25(OH)D (r = -0.36, P = 0.0001). 25(OH)D level of 15.4 ng/ml was determined as the optimal cut-off point in detecting possible secondary hyperparathyroidism.
  
  
  CONCLUSIONS
  To improve the community vitamin D status, in addition to population-based food fortification programs, educational programs seem essential; not only for general population, but also for the more educated groups.
authors.affiliation: Department of Internal Medicine and Rheumatology, Firouzgar General Hospital, Iran University of Medical Sciences, Tehran, Iran.
authors.forename: Mozhdeh
authors.initials: M
authors.lastname: Zabihiyeganeh
authors.affiliation: Department of Internal Medicine and Endocrinology, Booali General Hospital, Islamic Azad University, Tehran Medical Sciences Branch, Tehran, Iran.
authors.forename: S Adel
authors.initials: SA
authors.lastname: Jahed
authors.affiliation: Department of Internal Medicine and Rheumatology, Firouzgar General Hospital, Iran University of Medical Sciences, Tehran, Iran.
authors.forename: Samira
authors.initials: S
authors.lastname: Sarami
authors.affiliation: Department of Community Medicine, School of Medicine, Iran University of Medical Sciences, Tehran, Iran.
authors.forename: Marzieh
authors.initials: M
authors.lastname: Nojomi
keywords: Cut-off; hypovitaminosis D; medical students; parathyroid hormone; vitamin D deficiency