Causal relationship between gut microbiota and insulin-like growth factor 1: a bidirectional two-sample Mendelian...

Area of Science:

• Microbiome research
• Endocrinology
• Human genetics

Background:

• The interplay between gut microbiota and insulin-like growth factor 1 (IGF-1) is not well understood.
• Investigating this relationship is crucial for understanding metabolic and growth regulation.

Purpose of the Study:

• To explore the bidirectional causal relationship between gut microbiota composition and IGF-1 levels in men and women.
• To identify specific bacterial taxa influencing IGF-1 and vice versa.

Main Methods:

• Utilized Mendelian randomization (MR) analysis with single-nucleotide polymorphisms (SNPs) from large genome-wide association studies (GWASs).
• Employed the inverse variance weighted (IVW) method and performed sensitivity analyses for heterogeneity and pleiotropy.
• Derived gut microbiota data from the MiBioGen consortium and IGF-1 data from a separate GWAS.

Main Results:

• Forward MR analysis identified 11 bacterial taxa causally affecting IGF-1 in men and 14 in women (P < 0.05), though not significant after FDR correction.
• Reverse MR analysis showed IGF-1 causally affecting 9 bacterial taxa in men and 2 in women (P < 0.05).
• Post-FDR correction, IGF-1's causal effect on Actinomycetales order remained significant in men (P = 0.049).

Conclusions:

• Established a bidirectional causal relationship between gut microbiota and IGF-1 in both sexes.
• Suggests complex interactions between the gut microbiome and the IGF-1 axis influencing human health.