title: Winter 25-hydroxyvitamin D levels in young urban adults are affected by smoking, body mass index and educational level.
abstract: OBJECTIVE
  To study the relationship of winter 25-hydroxycholecalciferol (25-OHD) levels with age, education, place of residency, marital status and body mass index (BMI) as they may affect sun exposure, vitamin D synthesis and metabolism.
  
  
  METHODS
  Subjects (1952) answered a structured questionnaire concerning education, marital status and smoking; and body weight/height, and parathyroid hormone and 25-OHD were measured.
  
  
  RESULTS
  25-OHD levels were higher in the males with elementary and secondary education compared with higher education (46.8±18.5 and 43.7±16 vs 39.9±15.3 nmol/l, P<0.01). Vitamin D deficiency was more prevalent (16.7%, (13.1-20.2) vs 10.8%, (8.4-13.2), P=0.08) and sufficiency was less prevalent (24.6% (20-29.2) vs 33.7%, (29.5-37.8), P=0.005) in those with higher than secondary education. No differences were found among the females. Male smokers had lower 25-OHD than nonsmokers (40.2±16.6 vs 43.6±15.7 nmol/l, P=0.004). Deficiency was more prevalent in the male smokers than nonsmokers with secondary and higher education (secondary 16.6%, (10.1-22.4) vs 8.2%, (5.1-11.3), P=0.006; higher 27.4%, (17.7-37.1) vs 13.2%, (9.0-17.5), P=0.003). 25-OHD was lower in the obese than in the normal-weight females (34.6±16.2 vs 38.2±17.8 nmol/l, analysis of variance, P=0.014), but not males. Marital status was not related to 25-OHD. Only in the urban residents, increasing BMI in the young females increased the risk for vitamin D deficiency by 1%, and smoking had an odds ratio of 1.99 (1.05-3.78) in the young and 2.5 (1.07-5.75) in the middle-aged males.
  
  
  CONCLUSIONS
  Smoking and higher education in the males and obesity in the females were factors for vitamin D deficiency among Bulgarian urban population.
authors.affiliation: Department of Thyroid and Bone Mineral Diseases, University Hospital of Endocrinology, Medical University of Sofia, Sofia, Bulgaria.
authors.forename: A
authors.initials: A
authors.lastname: Shinkov
authors.affiliation: Department of Thyroid and Bone Mineral Diseases, University Hospital of Endocrinology, Medical University of Sofia, Sofia, Bulgaria.
authors.forename: A-M
authors.initials: AM
authors.lastname: Borissova
authors.affiliation: Department of Thyroid and Bone Mineral Diseases, University Hospital of Endocrinology, Medical University of Sofia, Sofia, Bulgaria.
authors.forename: L
authors.initials: L
authors.lastname: Dakovska
authors.affiliation: Department of Thyroid and Bone Mineral Diseases, University Hospital of Endocrinology, Medical University of Sofia, Sofia, Bulgaria.
authors.forename: J
authors.initials: J
authors.lastname: Vlahov
authors.affiliation: Central Laboratory of Therapeutic Drug Management and Clinical Pharmacology, Alexander University Hospital, Medical University of Sofia, Sofia, Bulgaria.
authors.forename: L
authors.initials: L
authors.lastname: Kassabova
authors.affiliation: Central Laboratory of Therapeutic Drug Management and Clinical Pharmacology, Alexander University Hospital, Medical University of Sofia, Sofia, Bulgaria.
authors.forename: D
authors.initials: D
authors.lastname: Svinarov
mesh_terms: D000328:Adult; D015992:Body Mass Index; D002031:Bulgaria / Q000453:epidemiology; D002112:Calcifediol / Q000097:blood; D004522:Educational Status; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000097:blood / Q000150:complications*; D016017:Odds Ratio; D010281:Parathyroid Hormone / Q000097:blood; D015995:Prevalence; D012307:Risk Factors; D012621:Seasons; D012737:Sex Factors; D012907:Smoking / Q000009:adverse effects* / Q000097:blood; D014505:Urban Population; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood; D014808:Vitamin D Deficiency / Q000097:blood / Q000453:epidemiology / Q000209:etiology*
chemical_list: D010281:Parathyroid Hormone; D014807:Vitamin D; C104450:25-hydroxyvitamin D; D002112:Calcifediol