title: Associations between vitamin D metabolites, antiretroviral therapy and bone mineral density in people with HIV.
abstract: BACKGROUND
  To see if vitamin D and antiretroviral therapy are associated with bone mineral density (BMD) in people with HIV.
  
  
  RESULTS
  Lower hip BMD was associated with tenofovir (an antiretroviral medicine) in those with 25(OH)D ≥50 nmol/L.
  
  
  CONCLUSIONS
  The relationship between antiretroviral therapy and hip BMD differs depending on vitamin D status.
  
  
  BACKGROUND
  People with HIV have an increased risk of low BMD and fractures. Antiretroviral therapy contributes to this increased risk. The aim of this study was to evaluate associations between vitamin D metabolites and antiretroviral therapy on BMD.
  
  
  METHODS
  The simplification of antiretroviral therapy with tenofovir-emtricitabine or abacavir-lamivudine trial (STEAL) was an open-label, prospective randomised non-inferiority study that compared simplification of current nucleoside reverse transcriptase inhibitors (NRTIs) to fixed-dose combination tenofovir-emtricitabine (TDF-FTC) or abacavir-lamivudine. Serum 25(OH)D and 1,25(OH)2D were measured in 160 individuals (90 receiving TDF-FTC, 70 receiving other NRTIs) at baseline from this study. Multivariable linear regression models were constructed to evaluate the covariates of 1,25(OH)2D and BMD.
  
  
  RESULTS
  Protease inhibitor use (p = 0.02) and higher body mass index (BMI) (p = 0.002) were associated with lower 1,25(OH)2D levels in those with 25(OH)D <50 nmol/L. However, TDF-FTC use (p = 0.01) was associated with higher 1,25(OH)2D levels, but only in those with 25(OH)D ≥50 nmol/L. White ethnicity (p = 0.02) and lower BMI (p < 0.001) in those with 25(OH)D <50 nmol/L and with TDF-FTC use (p = 0.008) in those with 25(OH)D ≥50 nmol/L were associated with lower hip BMD. TDF-FTC use, higher serum calcium and serum βCTX, winter, and lower bone-specific alkaline phosphatase (BALP) and BMI were associated with lower lumbar spine BMD.
  
  
  CONCLUSIONS
  TDF-FTC use (versus non-TDF-FTC use) was associated with lower hip BMD, and this difference was more pronounced in those with 25(OH)D ≥50 nmol/L. Serum 25(OH)D <50 nmol/L was associated with lower hip BMD in all participants. Therefore, the associations between antiretroviral therapy and hip BMD differ depending on vitamin D status.
authors.affiliation: Department of Medicine, University of Melbourne, Victoria, 3021, Australia. karenklassen@gmail.com.|Melbourne Sexual Health Centre, Alfred Health, 580 Swanston Street, Carlton, Melbourne, Victoria, Australia. karenklassen@gmail.com.
authors.forename: K M
authors.initials: KM
authors.lastname: Klassen
authors.affiliation: AusSun Research Lab, Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Queensland, Australia.
authors.forename: M G
authors.initials: MG
authors.lastname: Kimlin
authors.affiliation: Central Clinical School, Alfred Centre, Monash University, Melbourne, 3004, Australia.
authors.forename: C K
authors.initials: CK
authors.lastname: Fairley
authors.affiliation: The Kirby Institute, University of New South Wales, Sydney, Australia.
authors.forename: S
authors.initials: S
authors.lastname: Emery
authors.affiliation: School of Pharmacy and Medical Sciences, University of South Australia, Adelaide, South Australia, Australia.
authors.forename: P H
authors.initials: PH
authors.lastname: Anderson
authors.affiliation: Department of Medicine, University of Melbourne, Victoria, 3021, Australia.|Department of Medicine, School of Clinical Sciences, Monash University, Monash Health, Clayton, 3168, Victoria, Australia.
authors.forename: P R
authors.initials: PR
authors.lastname: Ebeling
mesh_terms: D000328:Adult; D019380:Anti-HIV Agents / Q000009:adverse effects* / Q000627:therapeutic use; D015992:Body Mass Index; D015519:Bone Density / Q000187:drug effects / Q000502:physiology; D002117:Calcitriol / Q000097:blood*; D015224:Dideoxynucleosides / Q000009:adverse effects / Q000627:therapeutic use; D004338:Drug Combinations; D000068679:Emtricitabine / Q000009:adverse effects / Q000627:therapeutic use; D005260:Female; D015658:HIV Infections / Q000097:blood / Q000188:drug therapy* / Q000503:physiopathology; D006621:Hip Joint / Q000503:physiopathology; D006801:Humans; D019259:Lamivudine / Q000009:adverse effects / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D010024:Osteoporosis / Q000097:blood / Q000139:chemically induced* / Q000503:physiopathology; D011446:Prospective Studies; D000068698:Tenofovir / Q000009:adverse effects / Q000627:therapeutic use; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood; D000099227:Abacavir
chemical_list: D019380:Anti-HIV Agents; D002117:Calcitriol; D015224:Dideoxynucleosides; D004338:Drug Combinations; D000068679:Emtricitabine; D019259:Lamivudine; D000068698:Tenofovir; D014807:Vitamin D; C492871:abacavir, lamivudine drug combination; D000099227:Abacavir; C104450:25-hydroxyvitamin D
keywords: Antiretroviral therapy; Bone; HIV; Vitamin D