Obese Adolescents With PCOS Have Altered Biodiversity and Relative Abundance in Gastrointestinal Microbiota

Abstract

Context: Alterations in gut microbiota relate to the metabolic syndrome, but have not been examined in at-risk obese youth with polycystic ovary syndrome (PCOS).

Objective: Compare the composition and diversity of the gut microbiota and associations with metabolic and hormonal measures between 2 groups of female adolescents with equal obesity with or without PCOS.

Design: Prospective, case-control cross-sectional study.

Setting: Tertiary-care center.

Participants: A total of 58 obese female adolescents (n = 37 with PCOS; 16.1 ± 0.3 years of age; body mass index [BMI] 98.5th percentile) and (n = 21 without PCOS; 14.5 ± 0.4 years of age; BMI 98.7th percentile).

Outcomes: Bacterial diversity, percent relative abundance (%RA), and correlations with hormonal and metabolic measures.

Results: Participants with PCOS had decreased α-diversity compared with the non-PCOS group (Shannon diversity P = 0.045 and evenness P = 0.0052). β-diversity, reflecting overall microbial composition, differed between groups (P < 0.001). PCOS had higher %RA of phyla Actinobacteria (P = 0.027), lower Bacteroidetes (P = 0.004), and similar Firmicutes and Proteobacteria. PCOS had lower %RA of families Bacteroidaceae (P < 0.001) and Porphyromonadaceae (P = 0.024) and higher Streptococcaceae (P = 0.047). Lower bacterial α-diversity was strongly associated with higher testosterone concentrations. Several individual taxa correlated with testosterone and metabolic measures within PCOS and across the entire cohort. Receiver operative curve analysis showed 6 taxa for which the %RA related to PCOS status and lower Bacteroidaceae conferred a 4.4-fold likelihood ratio for PCOS.

Conclusion: Alterations in the gut microbiota exist in obese adolescents with PCOS versus obese adolescents without PCOS and these changes relate to markers of metabolic disease and testosterone. Further work is needed to determine if microbiota changes are reflective of, or influencing, hormonal metabolism.

Keywords: PCOS; adolescence; metabolic syndrome; obesity.