title: A population-based study of Kaposi Sarcoma-associated herpesvirus seropositivity in Uganda using principal components analysis.
abstract: BACKGROUND
  Kaposi sarcoma-associated herpesvirus (KSHV) seropositivity is associated with sexual, environmental, and socioeconomic exposures. Whether these characteristics are independent risk factors is uncertain because of reliance on selected high-risk or hospital-based populations and incomplete adjustment for confounding. Therefore, we evaluated risk factors for KSHV seropositivity in a population-based study in Uganda using principal components analysis (PCA).
  
  
  METHODS
  The study population comprised 2,681 individuals randomly selected from a nationally-representative population-based HIV/AIDS sero-behavioral survey conducted in 2004/05. Questionnaire and laboratory data (97 variables) were transformed into a smaller set of uncorrelated variables using PCA. Multivariable logistic regression models were fitted to estimate odds ratios and 95% confidence intervals for the association between components and KSHV seropositivity.
  
  
  RESULTS
  Data were reduced to three principal components (PCs) labeled as Sexual behavioral, Socioeconomic, and Knowledge PCs. In crude analysis, KSHV seropositivity was associated with the Knowledge (ptrend = 0.012) and Socioeconomic components (ptrend = 0.0001), but not with the Sexual-behavioral component (ptrend = 0.066). KSHV seropositivity was associated with the Socioeconomic PC (ptrend = 0.037), but not with the Sexual-behavioral and Knowledge PCs, in the models including PCs, age, gender and geographic region.
  
  
  CONCLUSIONS
  Our results fit with the view that in Uganda socioeconomic characteristic may influence KSHV seropositivity. Conversely, the results fit with the interpretation that in Uganda sexual-behavioral characteristics, if relevant, contribute minimally.
authors: Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Department of Health and Human Services, Bethesda, MD, USA. changjo@umich.edu.
authors: Joanne T
authors: JT
authors: Chang
authors: Fatma M
authors: FM
authors: Shebl
authors: Ruth M
authors: RM
authors: Pfeiffer
authors: Benon
authors: B
authors: Biryahwaho
authors: Barry I
authors: BI
authors: Graubard
authors: Sam M
authors: SM
authors: Mbulaiteye