Bradshaw, Catriona S.Walker, JenniferFairley, Christopher K.Chen, Marcus Y.Tabrizi, Sepehr N.Donovan, BasilKaldor, John M.McNamee, KathrynUrban, EveWalker, SandraCurrie, MarianBirden, HudsonBowden, FrancisGarland, SuzannePirotta, MarieGurrin, LyleHocking, Jane S.2015-11-242015-11-241932-6203http://hdl.handle.net/1885/16699BACKGROUND 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]. CONCLUSION 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.This work was supported by the Commonwealth of Australia, as part of a National Chlamydia Pilot Program and the Australian National Health and Research Council (research grant number 509144). CSB, and JSH were supported by research fellowships issued by the Australian National Health and Medical Research Council (fellowship numbers 456164 and 566576 respectively). MP was supported by a Primary Health Care Research Evaluation and Development MidCareer Fellowship, Department of Health and Aging.8 pages© 2013 Bradshaw et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.adolescentadultaustraliacohort studiesfemalehumansincidenceprevalenceproportional hazards modelsrisk factorssexual partnersvaginosis, bacterialyoung adultcontraception behaviorsexual behavior2013-03-0510.1371/journal.pone.00576882015-12-11