Purpose: Bacterial vaginosis is the most common type of vaginal infection among women of reproductive age and accounted for at least one-third of all vulvovaginal infections. The main aim of this prospective study was to determine the risk factors that may be associated with the occurrence of bacterial vaginosis among the reproductive age group females in Assam. Materials and Methods: A total of two hundred married, nonpregnant females in the reproductive age group who complained of one or more symptoms suggesting lower genital tract infection were enrolled in this study. Detailed history of the patients was taken. Three high vaginal swabs were obtained after informed consent of the patients. Bacterial vaginosis was diagnosed on the basis of Amsel’s clinical criteria and Nugent’s Gram stain scoring method. Data was statistically analyzed using Chi-square test. Results: Our study found prevalence of bacterial vaginosis to be 51.5% (103/200) by Amsel’s criteria and 49% (98/200) by Nugent’s criteria respectively. Significant association was found between bacterial vaginosis and age, socioeconomic status, parity and contraceptives. However, no significant association was found between duration of marriage and stage of the menstrual cycle. Conclusion: A relatively higher prevalence rate of bacterial vaginosis was found in the population under study, which may be attributed to factors like low socioeconomic status and unhygienic practices. Barrier contraception was found to be an effective method for prevention of transmission of bacterial vaginosis. However, more studies may be needed to confirm and evaluate the causes of these associations, so that a preventive strategy can be planned.
Keywords: Assam, bacterial vaginosis, correlates, epidemiology, India
|How to cite this article:
Baruah FK, Sharma A, Das C, Hazarika NK, Agarwalla R. Prevalence and epidemiological correlates of bacterial vaginosis among nonpregnant females at a tertiary care center in Assam, India. Ann Trop Med Public Health 2014;7:91-5
|How to cite this URL:
Baruah FK, Sharma A, Das C, Hazarika NK, Agarwalla R. Prevalence and epidemiological correlates of bacterial vaginosis among nonpregnant females at a tertiary care center in Assam, India. Ann Trop Med Public Health [serial online] 2014 [cited 2017 Nov 14];7:91-5. Available from: https://www.atmph.org/text.asp?2014/7/2/91/146386
Bacterial vaginosis is a polymicrobial condition in which there is a decrease in vaginal acidity and in the concentration of lactobacilli accompanied by an increase of a 100-fold or more in the concentration of other micro-organisms. 
The high concentrations of anaerobic Gram-negative rods, peptostreptococci and other opportunistic pathogens in the lower genital tract place women with bacterial vaginosis at increased risk for genital infections and adverse pregnancy outcomes such as postabortal pelvic inflammatory disease, preterm birth, premature rupture of membranes, chorioamnionitis, and associated fetal loss, as well as postpartum and post-Cesarean endometritis and cuff cellulitis. ,
Bacterial vaginosis is considered a sexually enhanced disease rather than a sexually transmitted disease, in which frequency of intercourse plays a critical role.  Bacterial vaginosis is a common cause of vaginitis in women who are sexually active during child bearing age.  This disease may increase the risk of human immunodeficiency virus transmission also. 
The prevalence and causes of bacterial vaginosis are uncertain in part because the condition is often self-diagnosed and self-treated. Epidemiological studies of bacterial vaginosis are essential to understand its cause and prevalence in a particular population. The aim of this study was to determine the prevalence and epidemiological correlates of bacterial vaginosis among women attending Gynecology outpatient department and S.T.D. clinic of a tertiary care center in Assam, India.
|Materials and Methods|
Cross sectional study.
The study was done over a period of 1-year from August 2009 to July 2010.
The study was carried out at Gauhati Medical College, Assam.
Two hundred married, nonpregnant women were included in this study.
A total of two hundred married, nonpregnant women aged between 15 and 45 years, attending Gynecology Outpatient Department and S.T.D. clinic were enrolled prospectively into the study. All complained of one or more symptoms suggesting lower genital tract infection. Patients were excluded from the study only if they were menstruating or had received any treatment for vaginitis within the previous month.
A detailed history of the patients was taken by a pretested and predesigned schedule. Patients were categorized to different socioeconomic status on the basis of modified Kuppuswamy’s socioeconomic status scale. 
An informed consent was taken from each patient, and clinical examination was made of the vulva, vaginal walls and cervix to note any abnormality. After introduction of the vaginal speculum, the presence or absence of vaginal discharge was noted. Three high vaginal swabs were obtained from posterior vaginal fornixes which were used for the pH examination, amine test, wet mount and Gram stain preparation.
The diagnosis of bacterial vaginosis was established by detecting at least three of the four compound criteria viz. a thin, homogenous vaginal discharge, vaginal pH >4.5, a characteristic amine odor released upon addition of 10% KOH to the swab sample, presence of at least 20% clue cells in wet mounts.  In addition, Nugent’s Gram stain scoring system was also used.  The results of testing were recorded for all subjects.
Approval for conducting the study was taken from the Institutional Ethics Committee.
The database was structured in Microsoft Office Excel 2007 (Microsoft Corporation, Redmond, Washington) and analyzed using Statistical Package for the Social Sciences (SPSS) software 16 trial version (IBM Corporation, Armonk, New York). The differences between the groups with and without bacterial vaginosis were analyzed. The strength of the association was calculated using a confidence interval of 95% with P < 0.05 considered to be significant.
Our study included the patients based on symptomatology and showed a prevalence of 51.5% (103/200) of bacterial vaginosis by Amsel’s criteria and 49% (98/200) by Nugent’s criteria respectively. However, 42 (21%) patients were diagnosed as intermediate with a Nugent score of 4-6 [Table 1].
|Table 1: Comparison of criteria for diagnosis of bacterial vaginosis
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[Table 2] shows that epidemiological risk factors associated with bacterial vaginosis. Significant association was found between bacterial vaginosis and age, socioeconomic status, parity and contraceptives. No significant association was found between duration of marriage and stage of the menstrual cycle.
[Table 3] illustrates that the relationship between contraceptives and bacterial vaginosis was found to be significant. Out of 115 women who were using contraceptives, only 41 were found to be positive for bacterial vaginosis. However, incidence of bacterial vaginosis was significantly higher among intra-uterine device users and lower among those who were using barrier methods.
|Table 2: Epidemiological characteristics in patients of bacterial vaginosis
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|Table 3: Contraceptive use and bacterial vaginosis
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Since India has a high burden of reproductive morbidity, and bacterial vaginosis has been documented as a risk factor for adverse birth outcomes, this study investigated potentially modifiable behavioral risk factors for bacterial vaginosis.
The study revealed that bacterial vaginosis was prevalent in 51.5% cases, according to Amsel’s criteria, which was in the range of previous findings for other populations in India. , However, a lower prevalence of 28% has also been reported in an earlier study.  This could be due to different diagnostic criteria used by different authors and characteristics of the study population.
A higher prevalence rate of bacterial vaginosis was found in this study possibly because all of them were sexually active married women, largely from lower socioeconomic status.
Gram staining of vaginal secretions is more reliable with sensitivity of 89-93% and specificity of 70-83%.  The intermediate stage is considered to be a transitional phase, and the patients may go on to frank bacterial vaginosis. 
In an attempt to study the relationship of different variables with bacterial vaginosis, a significant relationship was observed between age groups and bacterial vaginosis. A higher prevalence of bacterial vaginosis was seen in patients who were ≤35 years of age. Some researchers have previously reported that the condition is more common among women who were >25 years of age  while some studies have found no significant association between age and prevalence of bacterial vaginosis. ,
Association between socioeconomic status and bacterial vaginosis was found to be statistically significant, which could be attributed to factors like unhygienic conditions and lack of treatment in lower socioeconomic status group. Bhalla et al. also reported that a low socioeconomic status was a risk factor for the development of bacterial vaginosis. 
Significant association was found between bacterial vaginosis and parity which was in confirmatory with earlier studies.  In this study, among the clinically diagnosed cases of bacterial vaginosis, 63.3% (50/79) had parity more than 2 whereas in patients with parity ≤2, the prevalence rate was only 43.8% (53/121). Amsel et al. found that the proportion of patients with a history of previous pregnancy and with higher mean number of pregnancies were associated with an increased incidence of bacterial vaginosis. 
Though an increased prevalence of bacterial vaginosis was found in women who were married for >5 years, but the association was not statistically significant. Amsel et al. also found an increased prevalence among women with increased years of sexual activity. 
According to a previous study, hormonal environment of the vagina alters on a monthly basis, with additional disturbances to the ecosystem produced by menstruation.  However, stage of the menstrual cycle did not influence the prevalence of bacterial vaginosis according to the following authors. ,, Similar finding was observed in this study in which the prevalence rate of 53.4% of bacterial vaginosis was found among women who were in the postovulatory stage, while a slightly lower rate of 46.6% was found among women in the preovulatory stage of the menstrual cycle.
Correlation of contraceptives and bacterial vaginosis was found to be statistically significant. Prevalence of bacterial vaginosis was significantly higher in women who were not using any contraceptives, while a lower rate was found in women using some form of contraception. Use of intra-uterine contraceptive devices was found to be a risk factor for bacterial vaginosis as reported in an earlier study also. 
However, the prevalence rate of bacterial vaginosis decreased significantly among barrier contraceptive users. In a previous study also, women using barrier contraceptives had a significantly lower prevalence of bacterial vaginosis than those using an intra-uterine device. 
Evidence for hormonal effects on bacterial vaginosis is supported by the fact that only 12% (5/42) of those using oral contraceptives are found positive for bacterial vaginosis. Two other groups of investigators have noted a lower prevalence of bacterial vaginosiis among oral contraceptive users. ,
The relationship between sexual activity and bacterial vaginosis remains unclear. This disease is not considered to be a typically sexually transmitted disease as there are reports of the occurrence of bacterial vaginosis in adolscents who are sexually inactive and also unsuccessful attempts of treating the partners of women complaining of recurrent bacterial vaginosis. , However, it is a sexually enhanced disease in which frequency of intercourse plays a critical role. 
Bacterial vaginosis is the most common type of vaginal infection among women of reproductive age and accounted for at least one-third of all vulvovaginal infections.  If undiagnosed and untreated, this condition may lead to major obstetric and gynaecological complications, which considerably increases treatment cost and hospitalization and also have a negative impact on female mortality rate.
Hence, it may be important to explore primary preventive strategies which target the risk factors or behavior for bacterial vaginosis. Many sexual and nonsexual risk factors have been found to be important in possible causation of bacterial vaginosis. As evident from this study, barrier contraception is an effective method for prevention of transmission of bacterial vaginosis. However, more studies may be needed to confirm and evaluate the causes of these associations so that a preventive strategy can be planned.
The authors are thankful to the ethical committee of Gauhati Medical College, Guwahati, Assam for allowing us to carry out the study.
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Source of Support: None, Conflict of Interest: None
[Table 1], [Table 2], [Table 3]