The incidences of vulvovaginal candidiasis (VVC) and bacterial vaginosis (BV) are especially high in young women, and women with a limited education and low-family income, according to a nationwide cohort study in the International Journal of Infectious Diseases.
Findings also showed that living in big cities may increase risk for VVC and BV.
The study of 2,357,711 Swedish women—aged 15 to 50 years—from nationwide primary health care and other national register data, was conducted in Sweden from 2001 to 2018. The total follow-up was roughly 34 million person-years.1
The incidence rates per 1,000 person-years for the first event of VVC and BV medically attended were 3.3 and 3.4, respectively.
Women with low education had about a 46% higher risk of BV, but that risk was reduced to around 25% after adjusting for other covariates.
In addition, women of non-Western origin were linked to increased risks in all analysis models. Compared to Swedish-born women, women from the Middle East/North Africa had the highest risk of VVC: hazard ratio (HR) = 2.77; 95% confidence (CI): 2.72 to 2.83.
This was followed by women from Africa—excluding North Africa—HR = 2.53; 95% CI: 2.45 to 2.61.Women from Latin America and the Caribbean had an HR of 2.18; 95% CI: 2.09 to 2.27.
These 3 country groups of women also had the highest prevalence of BV, with women from Latin America and the Caribbean having the highest risk—HR = 1.83; 95% CI: 1.75 to 1.92.
“Sweden has a high proportion of immigrants from around the globe who are granted equal access to the universal health care system. However, this does not inevitably grant equality of health and well-being, which has been repeatedly shown on several health outcomes by our research group and others,” wrote the authors. “This is again illustrated by the unequal distribution of BV and VVC among immigrant women.”
The increased risk of BV and VVC among women of non-Western origin could be due to biological predisposition and different health care seeking patterns, according to the authors, as well as cultural and sociodemographic differences in lifestyle, comorbidity, and genetic/biologic risk factors for these 2 common infections.
The study also found that diabetes mellitus was particularly connected to VVC, but the sociodemographic associations with VVC did not change substantially when accounting for diabetes mellitus or cervical cancer.
However, there was a stronger connection between contraceptive use and young age and low income for VVC. On the other hand, cervical cancer was linked to a 2-fold increased risk of BV.
Recent studies have concluded sociodemographic differences in the vaginal microbiome, including lower rates of Lactobacillus spp. in the vaginal microbiome of African and Hispanic women living in the United States compared to Caucasian women, and to a lesser degree among Asian women.
The authors noted this finding is significant because colonization and dominance of certain Lactobacillus spp. could play an important role in maintaining a healthy vaginal microbiota as depletion of these bacteria has been associated with increased risk of genitourinary infections, including BV and VVC.
The major limitation of the study is the investigators’ lack of access to microbiological data or BV-specific diagnoses, thus other similar miscellaneous vaginal conditions could be included in the diagnosis.
Jansaker F, Frimodt-Moller N, Li X, et al. Novel risk factors associated with common vaginal infections: a nationwide primary health care cohort study: novel risk factors for vaginal infections. Int J Infect Dis. March 2002. Volume 116; pages 380-386.