Factors associated with participation and attrition in a longitudinal study of bacterial vaginosis in Australian women who have sex with women.

OBJECTIVE: A number of social and sexual risk factors for bacterial vaginosis (BV) have been described. It is important to understand whether these factors are associated with non-participation or attrition of participants from longitudinal studies in order to examine potential for recruitment or attrition bias. We describe factors associated with participation and attrition in a 24-month prospective cohort study, investigating incident BV among Australian women who have sex with women. STUDY DESIGN AND SETTING: Participants negative for prevalent BV were offered enrolment in a longitudinal cohort study. Participants self-collected vaginal samples and completed questionnaires 3-monthly to endpoint (BV-positive/BV-negative by 24 months). Factors associated with participation in the cohort study were examined by logistic regression and factors associated with attrition from the cohort were examined by Cox regression. RESULTS: The cross-sectional study recruited 457 women. 334 BV-negative women were eligible for the cohort and 298 (89%, 95%CI 85, 92) enrolled. Lower educational levels (aOR 2.72, 95%CI 1.09, 6.83), smoking (aOR 2.44, 95%CI 1.13, 5.27), past BV symptoms (aOR 3.42, 95%CI 1.16, 10.10) and prior genital warts (aOR 2.71, 95%CI 1.14, 6.46) were associated with non-participation; a partner co-enrolling increased participation (aOR 3.73, 95%CI 1.43, 9.70). 248 participants (83%, 95%CI 78, 87) were retained to study endpoint (BV-negative at 24 months or BV-positive at any stage). Attrition was associated being <30 yrs (aHR 2.15, 95%CI 1.13, 4.10) and a male partner at enrolment (aHR 6.12, 95%CI 1.99, 18.82). CONCLUSION: We achieved high participation and retention levels in a prospective cohort study and report factors influencing participation and retention of participants over a 24-month study period, which will assist in the design and implementation of future cohort studies in sexual health and disease.

The influence of behaviors and relationships on the vaginal microbiota of women and their female partners: the WOW Health Study.

BACKGROUND: A community-based study of women who have sex with women (WSW) was performed to determine the burden of bacterial vaginosis (BV), and behavioral factors influencing the vaginal microbiota of women and their female sexual partners (FSPs), as measured by Nugent score (NS). METHODS: In a cross-sectional study of 18-55-year-old WSW recruited nationally, participants completed questionnaires and self-collected vaginal swab samples weekly on 3 occasions. BV was defined as an NS of 7-10. Factors associated with BV, stability of NS category, and concordance of these categories in co-enrolled couples were examined with multivariable logistic regression analysis. RESULTS: A total of 458 participants were recruited; 192 were co-enrolled with their FSP (96 couples). BV was detected in 125 women (27%; 95% confidence interval [CI], 23%-32%). BV was associated with ≥4 lifetime FSPs (adjusted odds ratio [AOR], 1.9; 95% CI, 1.2-3.1), an FSP with BV symptoms (AOR, 2.9; 1.0-8.2) and smoking, with ≥30 cigarettes per week showing greatest odds (AOR, 2.7; 1.5-5.0). Of 428 women returning ≥2 swab samples, 375 (88%) had a stable NS category across all samples, predominantly reflecting normal flora. Co-enrolled WSW were less likely to have BV (31% vs 23%; P = .07), and the majority (70%) were concordant for NS category (κ = 0.47; P ≤ .01), with most concordant for normal flora. Concordant NS category was associated with a relationship of >6 months (AOR, 4.7; 95% CI, 1.4-16.4) and frequent sexual contact (more than once per month; AOR, 2.7; 1.0-7.1). CONCLUSIONS: BV is associated with key behaviors and smoking practices in WSW, but longer-duration, sexually active WSW partnerships support a stable favorable vaginal microbiota.