Role of BMI in the relationship between dietary inflammatory index and non-alcoholic fatty liver disease: an intermediary analysis

Abstract

Objective

Previous studies have indicated that a pro-inflammatory diet is associated with non-alcoholic fatty liver disease (NAFLD), but the role of BMI remains ambiguous. We aim to study the intermediary effect of BMI on the relationship between dietary inflammatory properties and NAFLD.

Methods

A total of 19536 adult participants from the National Health and Nutrition Examination Surveys (NHANES) were included. Dietary inflammatory index (DII) was used to evaluate the dietary inflammatory properties and NAFLD was diagnosed by non-invasive biomarkers. Weighted multivariable logistic regression models estimated ORs and 95% CIs between DII and incidence of NAFLD. Interaction effect between DII and BMI on NAFLD was tested and the mediation analysis of BMI was performed.

Results

Higher DII scores, representing higher inflammatory potential of diet, were positively associated with a higher risk of NAFLD. Compared with the first quartile of DII, people from the second quartile (OR: 1.23 [95% CI: 1.04, 1.46]) to the fourth quartile (OR: 1.59 [95% CI: 1.31, 1.94]) have a higher risk of NAFLD before adjustment for BMI. The overall association was completely mediated by BMI (89.19%).

Conclusions

Our findings suggested that a higher pro-inflammatory potential diet was associated with a higher prevalence of NAFLD, and this association might be mediated by BMI.

Keywords:

• Dietary inflammatory index
• body mass index
• mediation analysis
• non-alcoholic fatty liver disease
• nutrition

Author contributions

S.H.Y. conceived the study. F.L.Q.N and Z.S.F. designed the study. F.L.Q.N. and Z.S.F. contributed to data collection and data analysis. F.L.Q.N. and Z.S.F. wrote the manuscript. S.H.Y. and Z.S.T. edited and reviewed the manuscript. All authors read and approved the final manuscript.

Disclosure statement

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Data availability statement

Data availability statement Publicly available datasets were analyzed in this study. This data can be found here: https://www.cdc.gov/nchs/nhanes/index.htm.

Additional information

Funding

This research received no external funding. This research was funded by National Natural Science Foundation of China grant number 81970496; Beijing Nova Program grant number Z201100006820147; Beijing Municipal Science and Technology Commission, grant number Z181100001718221.