title: Differences in vitamin D status and calcium metabolism in Saudi Arabian boys and girls aged 6 to 18 years: effects of age, gender, extent of veiling and physical activity with concomitant implications for bone health.
abstract: OBJECTIVE
  Few data exist looking at vitamin D status and bone health in school-aged boys and girls from Saudi Arabia. The present study aimed to determine the extent of poor vitamin D status in school boys and girls aged 6-18 years and to examine if there was any difference in status with age, physical activity and veiling and concomitant effects on bone.
  
  
  METHODS
  Cross-sectional study.
  
  
  METHODS
  Jeddah, Kingdom of Saudi Arabia.
  
  
  METHODS
  A total of 150 boys (7-16 years) and 150 girls (6-18 years) from local schools were divided into age categories: 6-9 years (elementary school); 10-12 years (secondary school); 13-14 years (middle years); 15-18 years (high school).
  
  
  RESULTS
  Vitamin D status was significantly lower in girls than boys in all age groups (P < 0.01), with the 15-18-year-old girls having the lowest level (22.0 (SD 9.4) nmol/l) in comparison to the 15-18-year-old boys (39.3 (SD 14.0) nmol/l) and the 6-9-year-old girls (41.2 (SD 9.3) nmol/l). Parathyroid hormone status was highest in the 15-18-year-old girls in comparison to boys of the same age. A total of 64 % of 15-18-year-old girls had 25-hydroxyvitamin D (25OHD) status <25 nmol/l in comparison to 31 % in the 13-14 years age category, 26 % in the 10-12 years category and 2.5 % in the 6-9 years category. No boys had 25OHD status <25 nmol/l. Fully veiled girls had lower 25OHD status than partly veiled or unveiled girls (P < 0.05). Low 25OHD and high parathyroid hormone was associated with lower bone mass in the 6-9 years and 13-14 years age groups (P < 0.05).
  
  
  CONCLUSIONS
  These data suggest significant hypovitaminosis D in older adolescent females, which is a cause for concern given that there is currently no public health policy for vitamin D in the Kingdom of Saudi Arabia.
authors.affiliation: Nutrition and Metabolism Department, Faculty of Health and Medical Sciences, University of Surrey, Guildford GU2 7XH, UK. maaalghamdi3@kau.edu.sa
authors.forename: Maryam A
authors.initials: MA
authors.lastname: Al-Ghamdi
authors.forename: Susan A
authors.initials: SA
authors.lastname: Lanham-New
authors.forename: Jalal A
authors.initials: JA
authors.lastname: Kahn
mesh_terms: D000293:Adolescent; D000367:Age Factors; D015519:Bone Density; D001842:Bone and Bones / Q000378:metabolism; D002118:Calcium / Q000097:blood / Q000172:deficiency* / Q000378:metabolism*; D002136:Calcium, Dietary / Q000008:administration & dosage; D002648:Child; D003020:Clothing; D003430:Cross-Sectional Studies; D015444:Exercise / Q000502:physiology; D005260:Female; D006306:Health Surveys; D006801:Humans; D008297:Male; D009752:Nutritional Status; D010281:Parathyroid Hormone / Q000097:blood; D012529:Saudi Arabia / Q000453:epidemiology; D012737:Sex Factors; D013472:Sunlight; D014807:Vitamin D / Q000008:administration & dosage / Q000031:analogs & derivatives / Q000097:blood*; D014808:Vitamin D Deficiency / Q000097:blood / Q000453:epidemiology*
chemical_list: D002136:Calcium, Dietary; D010281:Parathyroid Hormone; D014807:Vitamin D; C104450:25-hydroxyvitamin D; D002118:Calcium