Novel risk factors associated with common vaginal infections: a nationwide primary health care cohort study: Novel risk factors for vaginal infections

OBJECTIVE: This study aimed to estimate the association between potential risk factors and common vaginal infections using nationwide primary health care and other national registers.

METHODS: An open cohort study consisting of 2,357,711 women aged 15 years to 50 years (2001 to 2018) was conducted in Sweden. The outcomes were first event of vulvovaginal candidiasis (VVC) and bacterial vaginosis (BV) in relation to sociodemographic factors. Cox regression models were used. Sensitivity analyses including diabetes mellitus, contraceptive use, and cervical cancer were conducted.

RESULTS: The incidence rates per 1,000 person-years for VVC and BV were 3.3 (95% confidence interval [CI] 3.2-3.3) and 3.4 (95% CI 3.4-3.4), respectively. In the fully adjusted model, sociodemographic factors were significantly associated with both outcomes. Compared with Swedish-born women, women from Middle East/North Africa had the highest risk of VVC (hazard ratio [HR] 2.77, 95% CI, 2.72-2.83), followed by Africa (excluding North Africa) (HR 2.53, 95% CI, 2.45-2.61), and Latin America and the Caribbean (HR 2.18, 95% CI, 2.09-2.27). For BV, women from Latin America and the Caribbean had the highest risk (HR 1.83, 95% CI, 1.75-1.92).

CONCLUSION: This study presents novel risk factors associated with medically attended vaginal infections. Women from non-Western countries seem to develop these conditions disproportionately.