To evaluate the incidence and risks of developing small intestinal bacterial overgrowth (SIBO) in subjects with hypothyroidism or autoimmune thyroiditis, and to assess changes in small bowel microbial populations.
Key Findings:
SIBO prevalence was higher in the hypothyroid group (32.65%) compared to controls (15.17%).
10-year cumulative incidences of SIBO were higher in hypothyroidism (RR = 2.20) and autoimmune thyroiditis (RR = 2.40) subjects vs controls.
Levothyroxine treatment mitigated SIBO risk in hypothyroid (RR = 0.33) and autoimmune thyroiditis (RR = 0.78) subjects.
Genus Neisseria was part of the core microbiome in hypothyroid subjects, while Escherichia/Shigella was core in nonhypothyroid subjects.
Interpretation:
The findings suggest an increased risk of SIBO in individuals with hypothyroidism, potentially influenced by specific Gram-negative coliforms, which may be reduced with appropriate treatment. Further investigation into the mechanistic links is warranted.
Limitations:
The study's observational nature limits causal inferences, making it difficult to establish direct relationships.
Sample size for the hypothyroid group may restrict generalizability of the findings to broader populations.
Conclusion:
Hypothyroidism is associated with an increased risk of SIBO, which may be influenced by specific microbial populations and can be ameliorated by treatment.
by Margaret Wei, Sepideh Mehravar, Gabriela Leite, Parnian Naji, Gillian M Barlow, Ava Hosseini, Mohamad Rashid, Maritza Sanchez, Cristina M Fajardo, Mark Pimentel, Ruchi Mathur
