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Original research
Risk and protective factors associated with BV chronicity among women in Rakai, Uganda
  1. Marie E Thoma1,
  2. Rebecca M Brotman2,
  3. Ronald H Gray3,
  4. Nelson K Sewankambo4,5,
  5. Maria J Wawer3
  1. 1 Family Science, University of Maryland School of Public Health, College Park, Maryland, USA
  2. 2 Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, Maryland, USA
  3. 3 Epidemiology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland, USA
  4. 4 Department of Medicine, Makerere University School of Medicine, College of Helath Sciences, Kampala, Uganda
  5. 5 Rakai Health Sciences Program, Entebbe, Uganda
  1. Correspondence to Dr Marie E Thoma, Family Science, University of Maryland School of Public Health, College Park, MA 20742, USA; mthoma{at}


Objectives To assess risk and protective factors associated with bacterial vaginosis (BV) chronicity ascertained by Nugent score criteria.

Methods A longitudinal cohort study included 255 sexually experienced, postmenarcheal women who provided weekly self-collected vaginal swabs for up to 2 years. Vaginal swabs were scored using Nugent criteria and classified as normal (≤3), intermediate (4–6) and Nugent-BV (≥7). Detailed behavioural/health information were assessed every 6 months. A per-woman longitudinal summary measure of BV chronicity was defined as the percentage of each woman’s weekly vaginal assessments scored as Nugent-BV over a 6-month interval. Risk and protective factors associated with BV chronicity were assessed using multiple linear regression with generalised estimating equations.

Results Average BV chronicity was 39% across all follow-up periods. After adjustment, factors associated with BV chronicity included baseline Nugent-BV (β=35.3, 95% CI 28.6 to 42.0) compared with normal baseline Nugent scores and use of unprotected water for bathing (ie, rainwater, pond, lake/stream) (β=12.0, 95% CI 3.4 to 20.5) compared with protected water sources (ie, well, tap, borehole). Women had fewer BV occurrences if they were currently pregnant (β=−6.6, 95% CI −12.1 to 1.1), reported consistent condom use (β=−7.7, 95% CI −14.2 to 1.3) or their partner was circumcised (β=−5.8, 95% CI −11.3 to 0.3).

Conclusions Factors associated with higher and lower values of BV chronicity were multifactorial. Notably, higher values of BV chronicity were associated with potentially contaminated bathing water. Future studies should examine the role of waterborne microbial agents in the pathogenesis of BV.

  • bacterial vaginosis
  • epidemiology (general)
  • vaginal microbiology

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  • Handling editor Anna Maria Geretti

  • Twitter @ME_Thoma

  • Contributors MJW, NKS and RHG contributed to the planning, design and conduct of the initial study. MET, MJW, NKS and RHG contributed to planning, management and analysis of the data. MET, RMB, MJW, NKS and RHG contributed to the content, reporting and revision of the manuscript. All authors approved the final manuscript as submitted and are accountable for all aspects of the work. The corresponding author attests that all listed authors meet authorship criteria and that no others meeting the criteria have been omitted.

  • Funding This work was supported by grants from the National Institutes of Health (NIH), Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) no. R01AI47608 (to MJW), National Institute of Allergy and Infectious Diseases (NIAID) no. R01-AI119012 (to RMB) and a cooperative agreement from the Centers for Disease Control and Prevention no. R36PS001104 (to MET).

  • Competing interests None declared.

  • Patient consent for publication Not required.

  • Ethics approval Institutional Review Board (IRB) approvals were obtained from Uganda (the Scientific and Ethics Committee of the Uganda Virus Research Institute, Approved 21 Dec 1999—IRB numbers were not assigned at this time) and the United States (Johns Hopkins Bloomberg School of Public Health Committee on Human Research, IRB no. H.; Columbia University Medical Center IRB, no. 9264).

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data availability statement No data are available.