title: Vitamin D, Parathormone and Associated Minerals among Students in Zagazig District, Sharkia Governorate, Egypt.
abstract: OBJECTIVE
  To determine the prevalence of vitamin D deficiency and associated factors among students of age 13-18 years.
  
  
  METHODS
  
  
  
  METHODS
  Community-based cross sectional survey.
  
  
  METHODS
  Two schools were selected using multistage sampling techniques.
  
  
  METHODS
  Cluster sampling of all enrolled students (550 students).
  
  
  METHODS
  Serum levels of 25-hydroxyvitamin D (25 OHD), parathyroid hormone and calcium. Data was collected about nutritional intake, physical activity and lifestyle variables that are potential risk factors for hypovitaminosis D.
  
  
  RESULTS
  Hypovitaminosis D prevalence was 23.8%, of which 5.3% was deficiency and 18.5% insufficiency. Serum 25 OHD levels inversely correlated with parathyroid hormone levels (r=-0.206, P= 0.00). Low calcium and ionized calcium levels were 40.6% and 45.9%, respectively, and significantly correlated with vitamin D levels. Female students have significantly higher levels of hypovitaminosis D compared to males (29.3% to 15.0%, respectively) and the level of vitamin D significantly improved with increased age. Exposure to sun had a significant effect on vitamin D levels, and physical activity, soft drink consumption and smoking did not. Multinomial regression analysis revealed that age, sun exposure and Ca level were the only significant independent predictors of hypovitaminosis D among the studied group.
  
  
  CONCLUSIONS
  Our findings revealed that hypovitaminosis D is a prevalent health problem in adolescents, especially girls, who were at higher risk, and increased age and sun exposure improved vitamin D status among the studied group. There is therefore a need to consider vitamin D supplementation for school children together with increased awareness through a health education program.
authors.affiliation: 1 Public Health and Community Medicine Department, Faculty of Medicine, Zagazig University, Egypt.
authors.forename: Amal A
authors.initials: AA
authors.lastname: El Badawy
authors.forename: Mona M
authors.initials: MM
authors.lastname: Aboserea
authors.forename: Omnia S
authors.initials: OS
authors.lastname: El Seifi
authors.forename: Eman M
authors.initials: EM
authors.lastname: Mortada
authors.forename: Huny M
authors.initials: HM
authors.lastname: Bakry
authors.forename: Eman H
authors.initials: EH
authors.lastname: Waly
authors.forename: Nermin
authors.initials: N
authors.lastname: Raafat
authors.forename: Rasha L
authors.initials: RL
authors.lastname: Etewa
authors.forename: Samir A
authors.initials: SA
authors.lastname: El Badawy
mesh_terms: D000293:Adolescent; D000367:Age Factors; D002118:Calcium / Q000097:blood; D003430:Cross-Sectional Studies; D004032:Diet; D004534:Egypt / Q000453:epidemiology; D015444:Exercise; D005260:Female; D006801:Humans; D006961:Hyperparathyroidism / Q000150:complications / Q000453:epidemiology; D008019:Life Style; D008297:Male; D010281:Parathyroid Hormone / Q000097:blood*; D012307:Risk Factors; D012737:Sex Factors; D013472:Sunlight; D014807:Vitamin D / Q000031:analogs & derivatives / Q000097:blood; D014808:Vitamin D Deficiency / Q000150:complications / Q000175:diagnosis* / Q000453:epidemiology*
chemical_list: D010281:Parathyroid Hormone; D014807:Vitamin D; C104450:25-hydroxyvitamin D; D002118:Calcium
keywords: adolescents; calcium; ionized calcium; parathormone; vitamin D deficiency