title: Bone mineral density in young women aged 19-24 after 4-5 years of exclusive and mixed use of hormonal contraception.
abstract: BACKGROUND
  Use of depot-medroxyprogesterone acetate (DMPA), norethisterone enanthate (NET-EN) and low-dose combined oral contraceptives (COCs) has been associated with loss of bone mineral density (BMD) in adolescents. However, the effect of using a combination of these methods over time in this age group is limited. The aim of this cross-sectional study was to investigate BMD in young women (aged 19-24 years) with a history of mixed hormonal contraceptive use.
  
  
  METHODS
  BMD was measured at the spine, hip and femoral neck using dual X-ray absorptiometry. Women were classified into three groups: (1) injectable users (DMPA, NET-EN or both) (n=40), (2) mixed COC and injectable users (n=13) and (3) non-user control (n=41).
  
  
  RESULTS
  Women in the injectables-only user group were found to have lower BMDs compared to the non-user group at all three sites, and there was evidence of a difference in BMD between these two groups at the spine after adjusting for body mass index (p=.042), hip (p=.025) and femoral neck (p=.023). The mixed COC/injectable user group BMD values were lower than those for controls; however, there was no evidence of a significant difference between this group and the non-user group at any of the three sites.
  
  
  CONCLUSIONS
  This study suggests that BMD is lower in long-term injectable users but not when women have mixed injectable and COC use.
authors.affiliation: Reproductive Health and HIV Research Unit, Department of Obstetrics and Gynaecology, University of the Witwatersrand, Mayville, 4091, South Africa. mbeksinska@rhru.co.za
authors.forename: Mags E
authors.initials: ME
authors.lastname: Beksinska
authors.forename: Immo
authors.initials: I
authors.lastname: Kleinschmidt
authors.forename: Jenni A
authors.initials: JA
authors.lastname: Smit
authors.forename: Timothy M M
authors.initials: TM
authors.lastname: Farley
authors.forename: Helen V
authors.initials: HV
authors.lastname: Rees
mesh_terms: D001851:Bone Diseases, Metabolic / Q000139:chemically induced*; D016022:Case-Control Studies; D003277:Contraceptives, Oral, Combined / Q000009:adverse effects*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007273:Injections, Intramuscular; D017258:Medroxyprogesterone Acetate / Q000008:administration & dosage / Q000009:adverse effects*; D009640:Norethindrone / Q000008:administration & dosage / Q000009:adverse effects / Q000031:analogs & derivatives*; D013995:Time; D055815:Young Adult
chemical_list: D003277:Contraceptives, Oral, Combined; D017258:Medroxyprogesterone Acetate; C024319:norethindrone enanthate; D009640:Norethindrone