title: Vitamin D, parathyroid hormone levels and insulin sensitivity among obese young adult Saudis.
abstract: OBJECTIVE
  To determine alterations of vitamin D and parathyroid hormone levels and their relationship to insulin resistance among a sample of healthy young adult obese Saudis and to identify factors that might predict these alterations.
  
  
  METHODS
  Age and gender matched obese young (aged 18-25 years) adult Saudis (N = 76) with body mass index of > or = 30 and their lean controls (N = 84) were recruited after fulfilling exclusion and inclusion criteria from attendees of health facility at King Faisal University, Saudi Arabia. Selected participants were invited to a personal interview to gather information regarding socio-demographics. Fasting blood samples were assessed for the following essays: serum calcium, 25 OH vitamin D, inorganic phosphorus, intact parathyroid hormone (iPTH), serum insulin, fasting glucose, renal and liver function tests.
  
  
  RESULTS
  Vitamin D levels were significantly higher in lean controls, and showed significant decline in relation to obesity classes, hypovitaminosis D was found in 30% (38.2% obese vs. 22.7% in lean) and deficiency in 17.5% of subjects; (19% vs. obese 15.8%). iPTH was significantly higher in obese subjects. Secondary hyperparathyroidism was found in 48.1% (60.5% obese vs. 36.9% controls). Regression analysis showed that body mass index, serum calcium and creatinine levels were the main predictors for vitamin D level. Vitamin D is positively associated with fasting blood sugar (r = -.133, P = 0.09) and beta cell function index (r = .192, P = 0.08), negatively associated with HOMA-IR (r = -.122, P = .34) but without statistical significance after controlling of possible confounders.
  
  
  CONCLUSIONS
  Vitamin D level among young adult Saudi obese is negatively associated by body mass index and classes of obesity. Negative associations between vitamin D, iPTH levels and HOMA-IR exist but without statistical signifcance.
authors: Department of Internal Medicine, Endocrinology Section, College of Medicine, King Faisal University, Saudi Arabia.
authors: A I
authors: AI
authors: Al-Sultan
authors: T T
authors: TT
authors: Amin
authors: M A
authors: MA
authors: Abou-Seif
authors: M R
authors: MR
authors: Al Naboli
mesh_terms: D000293:Adolescent; D000328:Adult; D001786:Blood Glucose / Q000032:analysis; D015992:Body Mass Index; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D007328:Insulin / Q000097:blood; D007333:Insulin Resistance; D008055:Lipids / Q000097:blood; D008297:Male; D009765:Obesity / Q000378:metabolism*; D010281:Parathyroid Hormone / Q000097:blood*; D012529:Saudi Arabia; D014807:Vitamin D / Q000097:blood*; D055815:Young Adult
chemical_list: D001786:Blood Glucose; D007328:Insulin; D008055:Lipids; D010281:Parathyroid Hormone; D014807:Vitamin D