vulvovaginal candidiasis is caused by overgrowth of candida yeast species in the vagina and is characterized by curd - like vaginal discharge , itching , and erythema . vulvovaginal candidiasis has been associated with considerable direct and indirect economic costs , enhanced susceptibility to hiv infection , and is being investigated for a potential relationship with preterm birth . treatment of vulvovaginal candidiasis is warranted when a woman presenting with a complaint of symptoms consistent with vulvovaginal candidiasis also has laboratory confirmation of the presence of candida from a vaginal specimen . short - course azole - based treatment regimens are considered effective and safe   and are accessible and affordable in most settings . much of the epidemiologic literature concerning vulvovaginal candidiasis reports on studies in which women were queried on their self - reported history of vulvovaginal candidiasis , but without laboratory - confirmation of infection by candida . other studies , in which investigators only measure the presence of candida infection of the vagina , are not able to identify women with symptomatic vulvovaginal candidiasis disease ; this latter study design is frequently employed for studies conducted in low - income settings . few studies have diagnosed vulvovaginal candidiasis through laboratory confirmation of infection in symptomatic women , and few studies have measured the incidence of confirmed cases of vulvovaginal candidiasis . the lack of representative data on the epidemiologic features of laboratory - confirmed vulvovaginal candidiasis has been evident throughout the time in which vulvovaginal candidiasis has evolved from being considered a  nuisance infection  to a clinically relevant condition [ 7 , 8 ] . in india , only two studies have been conducted in which laboratory - confirmed vulvovaginal candidiasis was diagnosed in a community - based sample . diagnosed vulvovaginal candidiasis in 35% of 650 adult women living in rural maharashtra state , and prasad et al . diagnosed vulvovaginal candidiasis in 10% of 451 married , 1622 year old women in rural tamil nadu state [ 9 , 10 ] . however , neither study assessed the incidence of or identified risk factors for vulvovaginal candidiasis . as reduction of hiv transmission and of adverse birth outcomes remain public policy priorities in india , and studies have shown gynecological morbidity is extremely common [ 1215 ] , additional investigation of the epidemiologic features of vulvovaginal candidiasis is warranted . we examined the incidence , prevalence , and potential risk factors for vulvovaginal candidiasis among a cohort of women originally recruited for a study to examine the relationship of lower genital tract infections and incident herpes simplex virus type 2 infection . the recruitment and baseline descriptive features of the cohort of 898 sexually active , nonpregnant women between 16 and 30 years of age from communities around mysore , india has been previously described [ 17 , 18 ] . briefly , between 2005 and 2006 , women in the cohort completed three study visits ( at baseline and at three and six months ) , comprised of a structured interview , a clinical examination , and collection of cervicovaginal specimens for laboratory testing . trained interviewers collected sociodemographic and behavioral information , as well as reports of symptoms associated with gynecologic morbidity . study physicians performed a pelvic examination of each participant and recorded signs of vaginal abnormalities . during the examination , swabs of the posterior fornix of the vagina and blood specimens were collected , and vaginal ph measured . consistent with the us centers for disease control and prevention ( cdc ) 2006 diagnostic criteria   established prior to the baseline visit , vaginal candida infection was assessed from culture ( intray colorex yeast , biomed diagnostics , white city , or , usa ) though speciation of positive samples was not recorded . participants with positive culture for candida were diagnosed as having vulvovaginal candidiasis if they reported vaginal itching or discharge and had vaginal erythema or discharge observed on clinical examination . as part of the nugent - criteria scoring for laboratory diagnosis of bacterial vaginosis , the average number of lactobacillus - like cells ( morphotypes ) detected over several visual fields in light microscopy was enumerated , and given a score corresponding to averages of 0 , < 1 , 14 , 529 , and 30 . laboratory investigations were completed at holdsworth memorial hospital and vikram hospital in mysore , india . clinical and laboratory diagnostic criteria for the gynecological conditions examined in this cohort are detailed in table 1 . we calculated the visit - specific prevalence of vulvovaginal candidiasis and assessed whether this prevalence changed over the course of the study . next , we tabulated the number of women 's clinic visits with various vaginal symptoms reported or vaginal signs observed . among observations in which these vaginal signs or symptoms were recorded , we calculated the proportion in which a diagnosis of vulvovaginal candidiasis was made . finally , we examined the relationship between the prevalence of vulvovaginal candidiasis and sociodemographic characteristics and possible risk factors . categorical variables are the same as used in previous analyses ; cut - points of previously continuous measures were defined to create balanced strata of participants at the baseline visit [ 16 , 17 ] . we used a separate univariable regression model for each characteristic and risk factor . while counts ( e.g. , the number of diagnoses of vulvovaginal candidiasis ) are reported as observed , percentages , prevalences , trends in prevalence , 95% confidence intervals , and p values gee allows for parameter estimation when observations are correlated , in this case , due to multiple observations per participant over the course of the study . the gee models were specified with binary family , identity link , and exchangeable correlation . statistical analysis was conducted using stata 11.2 ( stata corp , college station , tx , usa ) . the study was approved by the committee for the protection of human subjects at the university of california , berkeley , and the asha kiran institutional review board of mysore , india ; all participating women provided written informed consent . the 898 women participating in the study contributed a total of 2551 study visits , with 800 women ( 89% ) attending all three study visits and another 53 women ( 6% ) attending two visits . the median age of the women at the baseline visit was 26 years ( interquartile range [ iqr ] 2429 years ) , and participants had been with their current sex partner for a median of nine years ( iqr 612 years ) . over one - quarter of the women had no formal education ( 27% ) . few women were nulliparous ( 15% ) , and very few women reported using oral contraception , condoms , or an intrauterine device at any point during the study . furthermore , less than 5% reported having oral sex or having had more than one lifetime sex partner . the mean prevalences of reproductive tract infections were as follows : trichomonas vaginalis ( 6% ) , clinical diagnosis ( amsel criteria ) of bacterial vaginosis ( 12% ) , laboratory diagnosis ( nugent criteria ) of bacterial vaginosis ( 16% ) , and infection with herpes simplex virus - type 2 ( 13% ) . at least 30 lactobacillus morphotypes were detected on the majority ( 66% ) of gram stains of vaginal swabs , with smaller proportions of swabs with 529 , 14 , < 1 , and 0 morphotypes detected ( 11 , 5 , 6 , and 12% , resp . ) . including all three study visits for which laboratory confirmation for diagnosis of vulvovaginal candidiasis was available ( n = 2528/2551 , 99% ) , we found that substantial proportions of the women reported vaginal itching ( 29% ) or vaginal discharge ( 31% ) or had vaginal erythema ( 9% ) or vaginal discharge ( 35% ) on examination . the positive predictive values of these signs and symptoms for predicting vulvovaginal candidiasis were low . a minority of women with these symptoms or signs was subsequently diagnosed with vulvovaginal candidiasis ( 18 , 15 , 25 , and 18% , resp . ) . combinations of the vaginal signs and symptoms were increasingly rare , though the probability of a correct diagnosis of vulvovaginal candidiasis increased to 41% when both signs and both symptoms were present ( table 2 ) . of the 885 , 180 ( 20% ) satisfied the case definition for diagnosis of vulvovaginal candidiasis , while the remaining 705 ( 80% ) were considered asymptomatic infection . the prevalence of vulvovaginal candidiasis declined over the three study visits from 77/893 ( 9% ) at baseline to 65/840 at three months ( 8% ) and 38/795 ( 5% ) at six months ( p value for trend < 0.001 ) . the incidence of vulvovaginal candidiasis was modest : of the 1487 baseline or three month study visits in which a woman was not diagnosed with vulvovaginal candidiasis , 72 ( 5% ) were positive for vulvovaginal candidiasis at the next study visit . of the 137 baseline or three - month study visits in which a woman was diagnosed with vulvovaginal candidiasis , 30 ( 28% ) were again diagnosed with vulvovaginal candidiasis at the next study visit . we did not find strong evidence for associations between sociodemographic characteristics and the diagnosis of vulvovaginal candidiasis . the prevalence of vulvovaginal candidiasis among women who first had sex before 15 years of age ( prevalence 4.4% , 95% ci 2.6 , 6.3 ) appeared lower than for women who first had sex between 15 and 18 years ( prevalence 7.5% , 95% ci 6.1 , 9.0 ) or over 19 years of age ( prevalence 8.2% , 95% ci 5.5 , 11.0 ) . there was a large difference in the prevalence of vulvovaginal candidiasis among those women with bacterial vaginosis diagnosed by clinical ( amsel ) criteria ( prevalence 12.0% , 95% ci 8.2 , 15.8 ) , compared to those women who were not diagnosed with bacterial vaginosis by clinical criteria ( prevalence 6.5% , 95% ci 5.3 , 7.6 ) . we did not find evidence of differences in the prevalence of vulvovaginal candidiasis by other laboratory diagnoses or behavioral characteristics ( table 3 ) . we examined the incidence , prevalence , and potential risk factors for vulvovaginal candidiasis among a cohort of reproductive - age women in mysore , india . among this cohort , we found evidence that a presumptive diagnosis of vulvovaginal candidiasis based only on presence of signs or symptoms , in absence of laboratory confirmation , would be mostly incorrect . consistent with previous research , we could not identify behavioral risk factors for vulvovaginal candidiasis , which provides impetus for additional investigation into intrinsic factors such as the composition of vaginal flora , the presence or absence of genetic factors , and the features of the host and local immune response . vaginal discharge , itching , and erythema , while quite common , were insufficient to diagnose vulvovaginal candidiasis in the absence of laboratory confirmation . had syndromic diagnosis been used to diagnose vulvovaginal candidiasis in this cohort , the positive predictive values would have been very low ( 1541% ) . our results are consistent with other studies detailing the overtreatment that results from the use of syndromic diagnosis based on vaginal discharge to diagnose vaginal conditions [ 2528 ] . previous findings also demonstrate that a minority of women with vaginal discharge have vulvovaginal candidiasis [ 25 , 2931 ] . thus , the diagnosis of vulvovaginal candidiasis based solely on signs or symptoms leads to overestimation of the prevalence of vulvovaginal candidiasis and its overtreatment , while leaving the actual cause of the vaginal symptoms untreated . this finding of misdiagnosis based on symptoms is also relevant for women who self - diagnose vulvovaginal candidiasis . the prevalence of laboratory - confirmed vulvovaginal candidiasis we observed is consistent with the results of two other community - based studies in india [ 9 , 10 ] . given that reproductive tract conditions account for nearly half of the days of illness experienced among women in this region of india , it is critical to understand the incidence and prevalence of individual conditions ; to our knowledge , this is the first study from india to describe the incidence of and possible risk factors for vulvovaginal candidiasis . the study visit - specific point prevalence of vulvovaginal candidiasis in this cohort decreased from 9% to 5% , and 72% of treated women were negative for vulvovaginal candidiasis at their next study visit , indicating successful provision of treatment . only 20% of those infected with candida were diagnosed as having vulvovaginal candidiasis , much lower than the 53% found in a community - based study in tamil nadu , india . we were not able to determine whether the 28% of women with a diagnosis of vulvovaginal candidiasis on two consecutive visits were cases in which , despite treatment , vulvovaginal candidiasis had cleared and then recurred . more likely , the repeat diagnoses at consecutive visits represent instances in which the vulvovaginal candidiasis was caused by candida species not susceptible to fluconazole treatment . previous research in india has found a high proportion of women infected by non - albicans candida species [ 29 , 33 ] , which are more resistant to treatment with azoles [ 34 , 35 ] . of the sociodemographic and behavioral characteristics we examined , only age at initiation of sexual activity appeared to be associated with the prevalence of vulvovaginal candidiasis , such that those with later initiation of sexual activity had a higher prevalence of vulvovaginal candidiasis . as the number of years women had been with their sex partners was not associated with vulvovaginal candidiasis , these two sociodemographic results appear discrepant and warrant additional investigation . as both diagnoses include vaginal discharge as a component of their respective diagnostic criteria , it is very likely there is misclassification between vulvovaginal candidiasis and clinically defined bacterial vaginosis . for example , women infected with candida may have discharge caused by bacterial vaginosis and could thus be misdiagnosed with vulvovaginal candidiasis . our findings emphasize the problems inherent in making diagnoses of vaginal conditions based on clinical examination alone [ 34 , 37 , 38 ] . we found some evidence that the prevalence of vulvovaginal candidiasis varied with the presence of lactobacillus morphotypes . the evidence for a relationship between the prevalence of vulvovaginal candidiasis and the presence of lactobacillus in the vagina is conflicting , including studies in which the h2o2-production status of lactobacillus was considered [ 24 , 3944 ] . recently , a prospective cohort study of female sex workers in kenya found the presence of lactobacillus , regardless of h2o2-production status , was positively associated with prevalent vulvovaginal candidiasis ( adjusted odds ratio ( aor ) 2.3 , 95% ci 0.8 , 6.4 ) , a relationship that was strengthened after restricting the analysis to women without a diagnosis of bacterial vaginosis ( aor 3.8 , 95% ci 1.3 , 10.8 ) . the loss of vaginal lactobacilli is the hypothesized mediator for the relationship between the receipt of antibiotics and the risk of vulvovaginal candidiasis [ 1 , 5 , 45 , 46 ] . the mediation hypothesis also underpins the long - standing interest in use of probiotic interventions to reduce the risk of developing vulvovaginal candidiasis [ 1 , 47 , 48 ] ; the results here do not provide strong support for this hypothesis . strengths of this study include a large effective sample size derived from the use of participants ' repeated observations , which allows for measurements of prevalence and incidence . additionally , other studies of vulvovaginal candidiasis in india use samples of symptomatic women recruited from clinics or used syndromic diagnosis and as a result were not able to estimate the community - level prevalence of vulvovaginal candidiasis . our study is one of the few to examine the prevalence of vulvovaginal candidiasis across a range in the number of lactobacillus morphotypes detected in the vagina ; examination of a dose - response provides better evidence , if any , of a biological relationship . first , the women in this cohort were recruited by nonrandom sampling ; unmeasured sampling bias can limit the generalizability of these results . second , because of the cross - sectional nature of our analysis , we can not make causal interpretations for the variations in the prevalence of vulvovaginal candidiasis observed here . third , we were not able to speciate the candida organisms detected . the associations between sociodemographic characteristics and potential risk factors and the prevalence of vulvovaginal candidiasis may differ by the candida species which infect women , which are known to vary considerably by geographical location . fourth , we could not verify whether participants were self - medicating between visits with antibiotics or antifungals , which would influence the incidence and prevalence measurements of vulvovaginal candidiasis . further , we could not immediately followup with women treated for vulvovaginal candidiasis , and so could not verify whether treatment was successful . finally , given the limited duration of the study , we could not identify a subset of women with recurrent vulvovaginal candidiasis , an important condition with epidemiologic features distinct from acute vulvovaginal candidiasis . we found that syndromic diagnosis will result in substantial overdiagnosis and overtreatment of vulvovaginal candidiasis - negative women . for correct diagnosis of vulvovaginal candidiasis laboratory confirmation of vaginal infection with candida is necessary as is a mean of assessing whether the discharge has been caused by bacterial vaginosis . absent accurate means of diagnosing vulvovaginal candidiasis , women remain at risk for vulvovaginal candidiasis - associated negative birth outcomes and acquisition of sexually transmitted infections . follow - up studies are needed of women infected with candida yeast species to determine the risk factors for the yeast 's overgrowth , as it appears that the examination of behavioral risk factors does not appear to be a fruitful avenue for further inquiry .
background . 
 vulvovaginal candidiasis is characterized by curd - like vaginal discharge and itching , and is associated with considerable health and economic costs . materials and methods . 
 we examined the incidence , prevalence , and risk factors for vulvovaginal candidiasis among a cohort of 898 women in south india . 
 participants completed three study visits over six months , comprised of a structured interview and a pelvic examination . 
 results . 
 the positive predictive values for diagnosis of vulvovaginal candidiasis using individual signs or symptoms were low ( < 19% ) . 
 we did not find strong evidence for associations between sociodemographic characteristics and the prevalence of vulvovaginal candidiasis . 
 women clinically diagnosed with bacterial vaginosis had a higher prevalence of vulvovaginal candidiasis ( prevalence 12% , 95% ci 8.2 , 15.8 ) compared to women assessed to be negative for bacterial vaginosis ( prevalence 6.5% , 95% 5.3 , 7.6 ) ; however , differences in the prevalence of vulvovaginal candidiasis were not observed by the presence or absence of laboratory - confirmed bacterial vaginosis . 
 conclusions . for correct diagnosis of vulvovaginal candidiasis , 
 laboratory confirmation of infection with candida is necessary as well as assessment of whether the discharge has been caused by bacterial vaginosis . 
 studies are needed of women infected with candida yeast species to determine the risk factors for yeast 's overgrowth .