Obesity is associated with lower bacterial vaginosis prevalence in menopausal but not pre-menopausal women in a retrospective analysis of the Women’s Interagency HIV Study

Abstract

The vaginal microbiota is known to impact women’s health, but the biological factors that influence the composition of the microbiota are not fully understood. We previously observed that levels of glycogen in the lumen of the vagina were higher in women that had a high body mass index (BMI). Vaginal glycogen is thought to impact the composition of the vaginal microbiota. We therefore sought to determine if BMI was associated having or not having bacterial vaginosis (BV), as determined by the Amsel criteria. We also hypothesized that increased blood glucose levels could lead to the previously-observed higher vaginal glycogen levels and therefore investigated if hemoglobin A1c levels were associated with BV. We analyzed data from the Women’s Interagency HIV Study using multiple multivariable (GEE) logistic regression models to assess the relationship between BMI, BV and blood glucose. Women with a BMI >30 kg/m2 (obese) had a lower rate (multivariable adjusted OR 0.87 (0.79–0.97), p = 0.009) of BV compared to the reference group (BMI 18.5–24.9 kg/m2). There was a significantly lower rate of BV in post-menopausal obese women compared to the post-menopausal reference group, but not in pre-menopausal women. HIV- post-menopausal obese women had a significantly lower rate of BV, but this was not seen in HIV+ post-menopausal obese women. Pre-menopausal women with a higher hemoglobin A1c (≥6.5%) had a significantly lower rate (multivariable adjusted OR 0.66 (0.49–0.91), p = 0.010) of BV compared to pre-menopausal women with normal hemoglobin A1c levels (<5.7%), but there was no difference in post-menopausal women. This study shows an inverse association of BMI with BV in post-menopausal women and hemoglobin A1c with BV in pre-menopausal women. Further studies are needed to confirm these relationships in other cohorts across different reproductive stages and to identify underlying mechanisms for these observed associations.

Insights into the role of vaginal microbiome in women's health

“…Recently, Daubert et al [53] reported an inverse association of BMI with BV in postmenopausal women. They concluded that postmenopausal obese women had a considerably lower rate of BV than the postmenopausal nonobese women [53]. Moreover, low estrogen levels in postmenopausal women, make postmenopausal women more susceptible to weight gain [54].…”

“…Elevated serum estrogens are associated with the development of breast cancer [52]. Recently, Daubert et al [53] reported an inverse association of BMI with BV in postmenopausal women. They concluded that postmenopausal obese women had a considerably lower rate of BV than the postmenopausal nonobese women [53].…”

Relationships between the vaginal microbiota and genitourinary syndrome of menopause symptoms in postmenopausal women: the Study of Women's Health Across the Nation

“…The glycogen provides nutritional support for Lactobacillus species, which produce lactic acid, thus lowering the vaginal pH and rendering the vaginal ecosystem inhospitable to other bacteria. [22][23][24] Distinguishing genitourinary symptoms attributed to menopause (GSM symptoms) from those that may be related to other diagnoses (ie, dermatological or medical conditions) can be as challenging in epidemiological studies as in clinical practice. In addition, reporting of GSM symptoms does not correlate well with physical examination findings of vaginal atrophy or with VMI.…”

“…A relationship between estrogen, the higher levels of estrogen in obesity, and the vaginal microbiota has been proposed in which estrogen stimulates the accumulation of glycogen in the most superficial layers of the squamous and mature vaginal epithelium. The glycogen provides nutritional support for Lactobacillus species, which produce lactic acid, thus lowering the vaginal pH and rendering the vaginal ecosystem inhospitable to other bacteria 22-24 …”

The Vaginal Microbiome in Health and Disease—What Role Do Common Intimate Hygiene Practices Play?

“…They also noticed that women with a BMI between 25 and 29.9 (overweight) had three times the odds of having >85% Lactobacillus abundance (OR 3.11, 95% CI 1.31–7.37). Daubert et al [ 37 ] examined the relationship between BV and BMI among women living with or at risk of HIV and reported that obese post-menopausal women had a significantly lower risk of BV compared with post-menopausal women with a normal BMI (18.5–24.9); however, this relationship was not significant among pre-menopausal women. In contrast to these studies, Brookheart et al [ 38 ] found that BV prevalence was highest among overweight and obese women compared with lean women, even after adjusting for race.…”