Is bacterial vaginosis a sexually transmitted infection?

To determine whether the risk factors associated with bacterial vaginosis (BV) are consistent with it being a sexually transmitted infection (STI) by comparing the characteristics of women with BV with those of women with infections recognised as being sexually and non-sexually transmitted.

A prospective cross sectional study was conducted among female patients presenting for diagnosis at a genitourinary medicine clinic in Sheffield between January 1996 and September 1998. Demographic and behavioural characteristics were reported from patient records and a standardised questionnaire was administered. Risk factor models for BV, two STIs, and two non-STIs were compiled using a multivariable logistic regression analysis.

Among the 8989 females under 45 years eligible for analysis, the prevalence of BV was 12.9%. Risk factors associated with BV included some in common with gonorrhoea and Chlamydia trachomatis and some that were not associated with these two STIs. Risk factors common to BV and the STIs included having had more than one sexual partner in the past 3 months, having a history of a bacterial STI, being of black Caribbean ethnicity, and living in a deprived area. However, BV had a contrasting age profile, being most prevalent among those over the age of 30. BV was also more common in those who were divorced.

BV is associated with some factors related to the acquisition of gonorrhoea and Chlamydia trachomatis. However, infection is not only determined by those factors and therefore factors other than sexual activity may be important in the development of the condition.