title: Prevalent and incident bacterial vaginosis are associated with sexual and contraceptive behaviours in young Australian women.
abstract: BACKGROUND
  To determine prevalence and incidence of bacterial vaginosis (BV) and risk factors in young sexually-active Australian women.
  
  
  METHODS
  1093 women aged 16-25 years were recruited from primary-care clinics. Participants completed 3-monthly questionnaires and self-collected vaginal smears 6-monthly for 12-months. The primary endpoint was a Nugent Score = 7-10 (BV) and the secondary endpoint was a NS = 4-10 (abnormal flora [AF]). BV and AF prevalence estimates and 95% confidence intervals (95%CI) were derived, and adjusted odds ratios (AOR) calculated to explore epidemiological associations with prevalent BV and AF. Proportional-hazards regression models were used to examine factors associated with incident BV and AF.
  
  
  RESULTS
  At baseline 129 women had BV [11.8% (95%CI: 9.4-14.2)] and 188 AF (17.2%; 15.1-19.5). Prevalent BV was associated with having a recent female partner [AOR = 2.1; 1.0-4.4] and lack of tertiary-education [AOR = 1.9; 1.2-3.0]; use of an oestrogen-containing contraceptive (OCC) was associated with reduced risk [AOR = 0.6; 0.4-0.9]. Prevalent AF was associated with the same factors, and additionally with >5 male partners (MSP) in 12-months [AOR = 1.8; 1.2-2.5)], and detection of C.trachomatis or M.genitalium [AOR = 2.1; 1.0-4.5]. There were 82 cases of incident BV (9.4%;7.7-11.7/100 person-years) and 129 with incident AF (14.8%; 12.5-17.6/100 person-years). Incident BV and AF were associated with a new MSP [adjusted rate ratio (ARR) = 1.5; 1.1-2.2 and ARR = 1.5; 1.1-2.0], respectively. OCC-use was associated with reduced risk of incident AF [ARR = 0.7; 0.5-1.0].
  
  
  CONCLUSIONS
  This paper presents BV and AF prevalence and incidence estimates from a large prospective cohort of young Australian women predominantly recruited from primary-care clinics. These data support the concept that sexual activity is strongly associated with the development of BV and AF and that use of an OCC is associated with reduced risk.
authors.affiliation: Melbourne Sexual Health Centre, Melbourne, Victoria, Australia. cbradshaw@mshc.org.au
authors.forename: Catriona S
authors.initials: CS
authors.lastname: Bradshaw
authors.forename: Jennifer
authors.initials: J
authors.lastname: Walker
authors.forename: Christopher K
authors.initials: CK
authors.lastname: Fairley
authors.forename: Marcus Y
authors.initials: MY
authors.lastname: Chen
authors.forename: Sepehr N
authors.initials: SN
authors.lastname: Tabrizi
authors.forename: Basil
authors.initials: B
authors.lastname: Donovan
authors.forename: John M
authors.initials: JM
authors.lastname: Kaldor
authors.forename: Kathryn
authors.initials: K
authors.lastname: McNamee
authors.forename: Eve
authors.initials: E
authors.lastname: Urban
authors.forename: Sandra
authors.initials: S
authors.lastname: Walker
authors.forename: Marian
authors.initials: M
authors.lastname: Currie
authors.forename: Hudson
authors.initials: H
authors.lastname: Birden
authors.forename: Francis
authors.initials: F
authors.lastname: Bowden
authors.forename: Suzanne
authors.initials: S
authors.lastname: Garland
authors.forename: Marie
authors.initials: M
authors.lastname: Pirotta
authors.forename: Lyle
authors.initials: L
authors.lastname: Gurrin
authors.forename: Jane S
authors.initials: JS
authors.lastname: Hocking
mesh_terms: D000293:Adolescent; D000328:Adult; D001315:Australia; D015331:Cohort Studies; D003268:Contraception Behavior; D005260:Female; D006801:Humans; D015994:Incidence; D015995:Prevalence; D016016:Proportional Hazards Models; D012307:Risk Factors; D012725:Sexual Behavior; D012747:Sexual Partners; D016585:Vaginosis, Bacterial / Q000175:diagnosis* / Q000453:epidemiology*; D055815:Young Adult