title: Longitudinal increase in vitamin D binding protein levels after initiation of tenofovir/lamivudine/efavirenz among individuals with HIV.
abstract: To examine longitudinal change in vitamin D binding protein (DBP) levels during the first year after initiation of tenofovir disoproxil fumarate (TDF)/lamivudine/efavirenz and compare these findings with concurrent changes in markers of skeletal metabolism.
  
  
  
  Secondary analysis of plasma samples collected from an ongoing multicenter clinical trial.
  
  
  
  Plasma samples collected at 0, 24, and 48 weeks after initiation of TDF + lamivudine + efavirenz from 134 adult participants enrolled in a multicenter randomized trial were analyzed. Data regarding sociodemographic and clinical characteristics were obtained as part of the parent study. Laboratory analyses included plasma DBP, intact parathyroid hormone, total 25-hydroxy vitamin D, phosphorus, the bone resorption marker collagen type 1 cross-linked C-telopeptide, and the bone formation marker total procollagen type 1 N-terminal propeptide. Repeated measures analysis of variance was used to measure changes in biomarkers over time.
  
  
  
  Our sample included 108 men and 26 women (mean age 33.6 ± 9.6 years). Median levels of DBP increased significantly from baseline to 48 weeks [154 (91.8-257.4) versus 198.3 (119.6-351.9) μg/ml, P < 0.001]. A concurrent rise in intact parathyroid hormone levels was observed over the same period [32.3 (24.4-40.9) versus 45.2 (35.1-60.4) pg/ml, P < 0.001]; however, 25-hydroxy vitamin D and phosphorus levels remained stable. Bone resorption and formation markers rapidly increased from 0 to 24 weeks, followed by a slight decline or plateau, but remained significantly elevated at 48 weeks (P < 0.001).
  
  
  
  Our study provides longitudinal data supporting a potential role for DBP in bone loss associated with TDF-based therapy. Further research to elucidate the mechanistic pathways and clinical impact of these findings is warranted.
authors.affiliation: aDepartment of Infectious Diseases, Peking Union Medical College Hospital, Beijing, China bSection of Rheumatology, Yale School of Medicine, New Haven, Connecticut, USA cDepartment of Endocrinology, Key Laboratory of Endocrinology, Peking Union Medical College Hospital, Beijing, China dSection of Endocrinology, Yale School of Medicine, New Haven, Connecticut eDivision of Infectious Diseases, Columbia University Medical Center, New York, USA fClinical Laboratory, Peking Union Medical College Hospital, Beijing, China.
authors.forename: Evelyn
authors.initials: E
authors.lastname: Hsieh
authors.forename: Liana
authors.initials: L
authors.lastname: Fraenkel
authors.forename: Yang
authors.initials: Y
authors.lastname: Han
authors.forename: Weibo
authors.initials: W
authors.lastname: Xia
authors.forename: Karl L
authors.initials: KL
authors.lastname: Insogna
authors.forename: Michael T
authors.initials: MT
authors.lastname: Yin
authors.forename: Ting
authors.initials: T
authors.lastname: Zhu
authors.forename: Xinqi
authors.initials: X
authors.lastname: Cheng
authors.forename: Taisheng
authors.initials: T
authors.lastname: Li
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000480:Alkynes; D019380:Anti-HIV Agents / Q000009:adverse effects / Q000627:therapeutic use*; D048588:Benzoxazines / Q000009:adverse effects / Q000627:therapeutic use*; D001862:Bone Resorption / Q000139:chemically induced; D003521:Cyclopropanes; D005260:Female; D015658:HIV Infections / Q000150:complications / Q000188:drug therapy* / Q000473:pathology*; D006801:Humans; D019259:Lamivudine / Q000009:adverse effects / Q000627:therapeutic use*; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D010949:Plasma / Q000737:chemistry; D000068698:Tenofovir / Q000009:adverse effects / Q000627:therapeutic use*; D014809:Vitamin D-Binding Protein / Q000097:blood*; D055815:Young Adult
chemical_list: D000480:Alkynes; D019380:Anti-HIV Agents; D048588:Benzoxazines; D003521:Cyclopropanes; D014809:Vitamin D-Binding Protein; D019259:Lamivudine; D000068698:Tenofovir; C098320:efavirenz