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●Diabetes mellitus – Women with diabetes mellitus who have poor glycemic control are more prone to vulvovaginal candidiasis than euglycemic women [24,25]. In particular, women with type 2 diabetes appear prone to nonalbicans Candida species [26].
●Antibiotic use – Use of broad-spectrum antibiotics significantly increases the risk of developing vulvovaginal candidiasis [27]. As many as one-quarter to one-third of women develop the disorder during or after taking these antibiotics because inhibition of normal bacterial flora favors growth of potential fungal pathogens, such as Candida. Administration of lactobacillus (oral or vaginal) during and for four days after antibiotic therapy does not prevent postantibiotic vulvovaginitis [28].
●Increased estrogen levels – Vulvovaginal candidiasis appears to occur more often in the setting of increased estrogen levels, such as pregnancy and postmenopausal estrogen therapy.
●Immunosuppression – Candidal infections are more common in immunosuppressed patients, such as those taking glucocorticoids or other immunosuppressive drugs, or with human immunodeficiency virus (HIV) infection [29]. (See "Glucocorticoid effects on the immune system" and "The natural history and clinical features of HIV infection in adults and adolescents".)
●Genetic – An analysis of whole exome sequencing from 160 European women with recurrent vulvovaginal candidiasis (RVVC) and 175 controls from the same regions demonstrated an association with polymorphisms in the SIGLEC15 gene, which produces a cell surface protein found on macrophages and dendritic cells [30]. Previous studies that evaluated known pathways identified associations between RVVC and polymorphisms in the TLR2 [31] and mannose-binding lectin genes [32]. Although these genetic variations are not modifiable risk factors, in the future, they may help guide treatment or prevention strategies.
The role of various contraceptive devices and sexual behaviors on the risk of Candida vulvovaginitis is less clear:
●Combined oral contraceptives (COC) – A 2013 systematic review of the literature found that, of 12 studies including more than 200 women, 7 demonstrated a significant association between COC use and prevalent or incident candidiasis, 2 found an association that was not statistically significant, and 3 found no association or a lower risk of candidiasis. However, the authors note that among the three highest quality studies, results were evenly split: one showed an increased risk in COC users, one showed no association, and one showed reduced risk in COC users [33]. Since that review, in one study of over 1000 HIV serodiscordant couples in Zambia, COC use was associated with lower risk for candidiasis, though pregnancy was associated with a higher risk [34].
●Contraceptive devices – Vaginal sponges, diaphragms, and intrauterine devices (IUDs) have been associated with vulvovaginal candidiasis, but not consistently. At least two studies have suggested that recurrent Candida vulvovaginitis in IUD users may be related to the ability of some species to attach to the IUD and form a biofilm rather than related to an intrinsic property of the IUD itself [35,36]. Spermicides are not associated with Candida infection. (See "Pericoital contraception: Diaphragm, cervical cap, spermicides, and sponge" and "Intrauterine contraception: Candidates and device selection".)
●Sexual behavior – Vulvovaginal candidiasis is not traditionally considered a sexually transmitted disease since it occurs in celibate women and since Candida species are considered part of the normal vaginal flora. This does not mean that sexual transmission of Candida does not occur or that vulvovaginal candidiasis is not associated with sexual activity. For example, an increased frequency of vulvovaginal candidiasis has been reported at the time most women begin regular sexual activity [6,22,37]. In addition, partners of infected women are four times more likely to be colonized than partners of uninfected women, and colonization is often the same strain in both partners. However, the number of episodes of vulvovaginal candidiasis a woman experiences does not appear to be related to her lifetime number of sexual partners or the frequency of coitus [22,38,39]. Women who exclusively have sex with women do not appear to have an increased risk of vulvovaginal infection [40].
The type of sex may be a factor. Infection may be linked to orogenital and, less commonly, anogenital sex. Evidence of a link between vulvovaginal candidiasis and hygienic habits (eg, douching, use of tampons/menstrual pads) or wearing tight or synthetic clothing is weak and conflicting [22,41-48].
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