Level of injury is an independent determining factor of gut dysbiosis in people with chronic spinal cord injury: a cross-sectional study

Study design
A cross-sectional study.

Objective
To investigate the correlations between gut microbiota and metabolic parameters in people with different levels of chronic spinal cord injury (SCI).

Setting
An SCI-specialized rehabilitation facility in a university hospital.

Methods
Forty-three participants with chronic SCI were recruited. Blood samples of each participant were collected for analysis of metabolic parameters. Feces were collected after the bowel opening method the patient routinely uses to evaluate fecal bacterial microbiota using quantitative RT-PCR. Body composition was examined using dual-energy x-ray absorptiometry (DEXA). Data were analyzed to evaluate the correlations between gut microbiota and other parameters.

Results
Of the 43 participants, 31 people (72.1%) were paraplegic and 12 people (27.9%) tetraplegic. Thirty-two people (74.4%) were diagnosed with obesity using the percentage of body fat (% body fat) criteria. The mean (SD) ratio of Firmicutes:Bacteroides (F/B), which represents the degree of gut dysbiosis, was 18.3 (2.45). Using stepwise multivariable linear regression analysis, both having tetraplegia and being diagnosed with obesity from % body fat evaluated by DEXA were independent positively-correlating factors of F/B (p < 0.001 and p = 0.001, respectively), indicating more severe gut dysbiosis in people with tetraplegia than paraplegia.

Conclusion
In people with chronic SCI, having tetraplegia and being diagnosed with obesity from % body fat evaluated by DEXA are independent positive-correlating factors of gut dysbiosis. These results indicate a significant association between gut microbiota and the characteristics of SCI as well as metabolic parameters.