Background

There are few large human population studies that examine how gut microbiota is associated with body mass, controlling for a wide variety of lifestyle factors.

Methods

We used a well-characterized sample of 2,833 adults (18-80 years, 51% women) who had not taken antibiotics in the past 6 months; and had no bowel disorder, bowel surgery, or diarrhea from the population-based 2015 China Health and Nutrition Survey. We compared microbial composition (16S rRNA) with respect to body mass index (BMI) using measures of β–diversity (principal coordinate analysis, PCoA), α-diversity (richness & Shannon Index), and taxa abundance. PCoA differences were tested with permutational multivariate analysis of variance (PERMANOVA) and other measures were compared using linear regression. Taxa-specific analyses were at genus (or lowest assigned) level and adjusted for multiple comparisons (false-discovery rate q-value<0.05). All analyses were adjusted for age, sex, province or megacity, batch effect, occupation, urbanization, education, income, Western diet, physical activity, smoking, alcohol consumption, and use of probiotics, non-steroid anti-inflammatory drugs, and proton-pump inhibitors.

Results

Microbial composition varied by BMI (PERMANOVA p-value=0.001). Eight taxa were significantly associated with BMI (q-value<0.05): genera Haemophilus, Weissella, and a genus from the Erysipelotrichaceae family were positively associated with BMI, while genera Ruminococcus, Corynebacterium, Akkermansia, a genus from Coriobacteriaceae family, and a genus from RF39 order were inversely associated with BMI. We found no evidence for the association between α-diversity measures and BMI.

Conclusions

We found a strong association between the gut microbial community and BMI in Chinese adults. Genera associated with BMI are involved in pathways related to amino acid, lipid, and glucose metabolism, and have been linked to intestinal immunity. These data support the potential of gut microbiota as therapeutic targets for obesity.