title: High prevalence of hypovitaminosis D in Mexicans aged 14 years and older and its correlation with parathyroid hormone.
abstract: A sample of 585 healthy subjects 14 years and older was studied to estimate the status of 25-hydroxyvitamin D (25(OH)D) and its correlation with parathyroid hormone in healthy Mexicans. In 43.6 % of the sample, levels of vitamin D were below 20 ng/mL and showed an inverse relationship with parathyroid hormone (PTH; p < 0.01).
  
  
  OBJECTIVE
  The purpose of the present study was to estimate the status of 25-hydroxyvitamin D (25(OH)D) and its correlation with parathyroid hormone in healthy Mexicans.
  
  
  METHODS
  A cross-sectional study of 585 healthy subjects 14 years and older was carried out. A questionnaire including all relevant demographics, medical history, and lifestyle factors was applied by trained interviewers. Morning fasting blood was collected in all subjects for estimation of 25(OH)D using liquid chromatography-tandem mass spectrometry and PTH hormone-intact molecule by RIA.
  
  
  RESULTS
  Of the group of 585 subjects, 54.1 % were women; the sample was divided in three age groups (14-29, 30-50, and >51). Only 9.6 % of the total sample had levels of 25(OH)D above 30 ng/mL; 46.8 % were between 20 and 29 ng/mL, and 43.6 % were below 20 ng/mL. Regarding PTH, a three-phase model was identified using regression smoothing scatterplot (LOESS), with two thresholds of 25(OH)D of 19 and 29 ng/mL. Phase 1 (25(OH)D <19 ng/mL) showed an inverse relationship with PTH (p < 0.01); phases 2 and 3 showed no significant relationship.
  
  
  CONCLUSIONS
  Our results show that 43.6 % of the Mexicans in this study have deficient concentration levels of vitamin D. The cutoff point of 20 ng/mL of 25(OH)D established by the Institute of Medicine has a biological and statistically significant relationship with PTH levels in the Mexican population, independently of principal confounding factors. Like many other countries, Mexico could be included in the global epidemic of hypovitaminosis D.
authors.affiliation: Clinical Epidemiology Unit, Hospital Infantil Federico Gómez-Facultad de Medina UNAM, Calle Dr. Márquez 162, Cuahtemoc, Doctores, 06720, México, D.F., Mexico, patriciaclark@prodigy.net.mx.
authors.forename: Patricia
authors.initials: P
authors.lastname: Clark
authors.forename: Nalleli
authors.initials: N
authors.lastname: Vivanco-Muñoz
authors.forename: Juan Talavera
authors.initials: JT
authors.lastname: Piña
authors.forename: Rodolfo
authors.initials: R
authors.lastname: Rivas-Ruiz
authors.forename: Gerardo
authors.initials: G
authors.lastname: Huitrón
authors.forename: Gabriela
authors.initials: G
authors.lastname: Chico-Barba
authors.forename: Alfredo A
authors.initials: AA
authors.lastname: Reza-Albarrán
mesh_terms: D000293:Adolescent; D000328:Adult; D003430:Cross-Sectional Studies; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D008019:Life Style; D008297:Male; D008800:Mexico / Q000453:epidemiology; D008875:Middle Aged; D010281:Parathyroid Hormone / Q000097:blood*; D015995:Prevalence; D012016:Reference Values; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood; D014808:Vitamin D Deficiency / Q000097:blood / Q000453:epidemiology*; D055815:Young Adult
chemical_list: D010281:Parathyroid Hormone; D014807:Vitamin D; C104450:25-hydroxyvitamin D