title: Vitamin D status in Bulgaria--winter data.
abstract: We assume that 25(OH)D level >50 nmol/l is necessary for adequate parathyroid hormone (PTH) suppression in our population. The epidemiology of vitamin D status in Bulgarian population shows deficiency in 21.3 %, insufficiency in 54.5 % and sufficiency in 24.2 %. The mean level of 25(ОН)D for the Bulgarian population is 38.75 nmol/l (95 % CI, 38.00-39.49).
  
  
  OBJECTIVE
  The aim of the present study was to investigate the vitamin D levels in Bulgaria and the prevalence of vitamin D deficiency depending on gender and age, as well as to define population-specific 25(OH)D sufficiency thresholds through the relationship with PTH.
  
  
  METHODS
  This cross-sectional study was conducted in January-February 2012 and included 2,032 subjects in 12 regions-1,076 women (53 %) and 956 men (47 %), mean age 49.30 ± 14.75 years (20-80 years), divided into three age groups: young (20-44 years, n = 894), middle-aged (45-59 years, n = 534), and elderly (≥60 years, n = 604). 25(OH)D and PTH were measured in all subjects.
  
  
  RESULTS
  The mean level of 25(ОН)D was 38.75 nmol/l (95 % CI, 38.00-39.49). The men had significantly higher 25(ОН)D levels in comparison to women (41.51 nmol/l (95 % CI, 40.45-42.56) vs.36.29 nmol/l (95 % CI, 35.27-37.32), p < 0.05). We did not find significant differences in the 25(ОН)D levels between the three age groups. The prevalence of vitamin D deficiency was 21.3 %; insufficiency, 54.5 %; and sufficiency, 24.2 %. Deficiency was more prevalent in women (26.9 %) than in men (15.1 %), p < 0.001. PTH started to rise over the upper limit of the reference range at mean 25(OH)D 50 nmol/l. We assume that levels over 50 nmol/l are necessary for adequate PTH suppression.
  
  
  CONCLUSIONS
  The status of vitamin D in our country is worrisome, and it is largely underestimated. The defining of a vitamin D sufficiency levels may help the devising of adequate strategies for prevention and treatment in clinical practice.
authors.affiliation: Department of Thyroid and Bone Mineral Diseases, University Hospital of Endocrinology, Medical University of Sofia, 2 ZdraveStr, Sofia 1431, Bulgaria. anmarbor@abv.bg
authors.forename: A-M
authors.initials: AM
authors.lastname: Borissova
authors.forename: A
authors.initials: A
authors.lastname: Shinkov
authors.forename: J
authors.initials: J
authors.lastname: Vlahov
authors.forename: L
authors.initials: L
authors.lastname: Dakovska
authors.forename: T
authors.initials: T
authors.lastname: Todorov
authors.forename: D
authors.initials: D
authors.lastname: Svinarov
authors.forename: L
authors.initials: L
authors.lastname: Kassabova
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002031:Bulgaria / Q000453:epidemiology; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010281:Parathyroid Hormone / Q000097:blood*; D015995:Prevalence; D014807:Vitamin D / Q000097:blood*; D014808:Vitamin D Deficiency / Q000453:epidemiology*; D055815:Young Adult
chemical_list: D010281:Parathyroid Hormone; D014807:Vitamin D