Alterations of gut microbiota biodiversity and relative abundance in women with PCOS: A systematic review and meta-analysis.
Level 3 - non-randomized controlled study
Systematic review and meta-analysis of observational studies
PubMed 37739322 · doi:10.1016/j.micpath.2023.106370
What was done
A systematic review and meta-analysis of PubMed, Web of Science, Embase, Cochrane Library, and Ovid was conducted up to March 28, 2023, without language or regional restrictions. Risk of bias was evaluated using the Newcastle-Ottawa Scale, and pooled effects were calculated using Stata 15.1 to assess gut microbiota alpha diversity indices and taxonomic relative abundances between women with PCOS and healthy controls.
What was found
Nineteen human observational studies including 617 women with PCOS and 439 healthy individuals were identified. Women with PCOS had significantly lower alpha diversity compared to controls: Chao index (WMD -28.88, 95% CI -45.78 to -11.98, I2 = 100%), Shannon index (WMD -0.11, 95% CI -0.18 to 0.00, I2 = 92.2%), and observed operational taxonomic units (WMD -23.48, 95% CI -34.44 to -12.53, I2 = 99.6%). For relative abundance, Bacteroidaceae was significantly higher in PCOS (WMD 0.12, 95% CI 0.02 to 0.22, I2 = 9.2%). No significant differences were observed across 25 other evaluated taxa, including Actinobacteria, Bacteroidetes, Firmicutes, Proteobacteria, Bifidobacteriaceae, Clostridiaceae, Enterobacteriaceae, Lachnospiraceae, Prevotellaceae, Bacteroides, Bifidobacterium, and Faecalibacterium.
Why it matters
This review synthesizes pooled clinical data showing reduced gut bacterial richness and diversity in PCOS, identifying specific microbial changes that may inform future mechanistic and biomarker investigations.
Limits
All included studies were observational, which precludes causal inference. Statistical heterogeneity was extremely high for all alpha diversity measures (I2 between 92.2% and 100%). Total sample size across 19 studies was modest (averaging ~55 subjects per study), and potential confounding factors such as body mass index, diet, and medication use were not reported in the abstract.
Cited by
- supports Women diagnosed with polycystic ovary syndrome (PCOS) exhibit an altered gut microbiome and disrupted gut-brain axis compared to healthy controls.