title: A cross-sectional study of the forearm bone density of long-term users of levonorgestrel-releasing intrauterine system.
abstract: BACKGROUND
  There are concerns about the effect of hormonal contraceptives on bone mineral density (BMD), but there is currently no information available on the effect of the levonorgestrel-releasing intrauterine system (LNG-IUS) on BMD. The objective of this study was to compare the BMD of LNG-IUS users with that of controls using the TCu380A intrauterine device (IUD).
  
  
  METHODS
  A cross-sectional study paired 53 women, aged 25-51 years, who had been using the LNG-IUS for 7 years, with 53 IUD users, according to age (+/-1 year) and body mass index (BMI; kg/m2) (+/-1). BMD was evaluated at the midshaft of the ulna and the distal radius of the nondominant forearm using double X-ray absorptiometry.
  
  
  RESULTS
  Mean age of women was 34 years. BMI was slightly over 25 in both groups. Estradiol was normal. Mean BMD was 0.469 +/- 0.008 and 0.467 +/- 0.009 and 0.409 +/- 0.009 and 0.411 +/- 0.009 at the midshaft of the ulna and distal radius in LNG-IUS and IUD users, respectively, without significant differences.
  
  
  CONCLUSIONS
  Women aged 25-51 years, using the LNG-IUS for 7 years, had a mean BMD similar to that of the control group of TCu380A IUD users.
authors.affiliation: Human Reproduction Unit, Department of Obstetrics and Gynaecology, School of Medicine, Universidade Estadual de Campinas (UNICAMP), Campinas, Brazil. bahamond@caism.unicamp.br
authors.forename: Luis
authors.initials: L
authors.lastname: Bahamondes
authors.forename: Ximena
authors.initials: X
authors.lastname: Espejo-Arce
authors.forename: Maria M
authors.initials: MM
authors.lastname: Hidalgo
authors.forename: Creusa
authors.initials: C
authors.lastname: Hidalgo-Regina
authors.forename: Cássia
authors.initials: C
authors.lastname: Teatin-Juliato
authors.forename: Carlos A
authors.initials: CA
authors.lastname: Petta
mesh_terms: D015502:Absorptiometry, Photon; D000328:Adult; D015519:Bone Density / Q000187:drug effects*; D003271:Contraceptive Agents, Female / Q000008:administration & dosage*; D003430:Cross-Sectional Studies; D004958:Estradiol / Q000097:blood; D005260:Female; D005542:Forearm / Q000000981:diagnostic imaging; D006801:Humans; D007436:Intrauterine Devices, Medicated; D016912:Levonorgestrel / Q000008:administration & dosage*; D008875:Middle Aged; D011884:Radius / Q000528:radiation effects*; D014457:Ulna / Q000528:radiation effects*
chemical_list: D003271:Contraceptive Agents, Female; D004958:Estradiol; D016912:Levonorgestrel