Interplay between colorectal cancer-related lifestyles and the gut microbiome: an exploratory analysis of metagenomic data.

CRC-related lifestyle patterns explained a small but statistically significant proportion of variation in gut microbial composition.

• The CRC lifestyle index explained 0.2% of the variation in microbial composition between participants (p < 0.05).
• Associations were assessed using permutational multivariate ANOVA adjusted for relevant confounders.
• The study included 1,228 Finnish adults aged 25–64 years from the National FINRISK/FINDIET 2002 Study.

Higher-risk lifestyles for CRC were associated with lower microbial diversity.

• The association between higher-risk CRC lifestyles and lower microbial diversity was statistically significant (β 0.037, p 0.009).
• Diversity was assessed using shallow shotgun metagenome sequencing.
• Linear regression was used to assess associations between the lifestyle index and microbial diversity, adjusted for relevant confounders.

Higher-risk CRC lifestyles were associated with greater relative abundance of species in the family Lachnospiraceae and related genera.

• Species primarily representing the family Lachnospiraceae were more abundant in individuals with higher-risk lifestyles.
• Specific genera associated with higher-risk lifestyles included Dorea and Mediterraneibacter.
• The association was statistically significant (p < 0.0001).

Higher-risk CRC lifestyles were associated with lower relative abundance of species within the genus Bifidobacterium.

• Lower relative abundance of Bifidobacterium species was observed in participants with higher-risk CRC lifestyles.
• The association was statistically significant (p < 0.0001).
• Bifidobacterium species are generally considered potentially beneficial microbial features.

The CRC lifestyle index was constructed from nine major risk factors for colorectal cancer, with lower index scores reflecting higher-risk lifestyles.

• The index was based on nine major CRC risk factors.
• Lower index points reflected higher-risk lifestyles for CRC.
• Lifestyle and background factor information was obtained through self-administered questionnaires, and dietary data were gathered using a 48-h dietary recall.