title: What is HIV-associated lipodystrophy? Defining fat distribution changes in HIV infection.
abstract: OBJECTIVE
  The prevalence of lipodystrophy in HIV infection reported in the early literature has varied widely due in part to the different methods used in assessing and defining lipodystrophy in studies. There remains a lack of clarity regarding whether the peripheral lipoatrophy and central lipohypertrophy initially described in HIV infection are a result of separate mechanisms or a single mechanism. We review the current methods used to assess and define lipodystrophy in HIV infection; the prevalence and incidence of lipodystrophy reported in the recent HIV literature; and future directions in elucidating the morphologic changes associated with HIV infection.
  
  
  RESULTS
  Different methods of assessing and defining lipodystrophy continue to lead to varying prevalence and incidence rates in recent large cross-sectional and prospective studies. Recent studies that include a predominantly HIV-uninfected comparison group and utilize bi-directional surveys to describe fat loss and fat gain in both peripheral and central body sites suggest that there is an HIV-associated lipoatrophy that affects both peripheral and central sites. In one study that used objective measures to quantify fat such as magnetic resonance imaging, HIV-associated subcutaneous lipoatrophy appeared to predominate when compared with a healthy control group.
  
  
  CONCLUSIONS
  Peripheral and central lipoatrophy affecting subcutaneous fat is emerging as the dominant morphologic change associated with HIV infection when compared with those without known HIV infection. Studies of lipodystrophy in HIV infection should focus on lipoatrophy using direct measures of fat when possible.
authors.affiliation: Department of Medicine, University of California, San Francisco and San Francisco Veterans Affairs Medical Center, San Francisco, California 94121, USA. ptien@medicine.ucsf.edu
authors.forename: Phyllis C
authors.initials: PC
authors.lastname: Tien
authors.forename: Carl
authors.initials: C
authors.lastname: Grunfeld
mesh_terms: D003430:Cross-Sectional Studies; D015658:HIV Infections; D006801:Humans; D015994:Incidence; D008060:Lipodystrophy / Q000453:epidemiology / Q000209:etiology / Q000503:physiopathology*; D008137:Longitudinal Studies; D015995:Prevalence