Effect of serum vitamin D on metabolic associated fatty liver disease: a large population-based study

Abstract

Background

Several studies have revealed that serum vitamin D is an important factor for metabolic associated fatty liver disease (MAFLD), but there had been no consistent conclusion.

Methods

Of 427,507 subjects who underwent health examination, 83,625 who met the inclusion criteria were included in a cross-sectional analysis. Clinical and laboratory data were collected for analysis. MAFLD was diagnosed by abdominal imaging.

Results

Multivariate linear regression models discovered a negative association between serum vitamin D and MAFLD (OR: 0.92, 95% CI: 0.90 to 0.94, p = .001), after adjusting for other well-identified risk factors. The same result was found when serum vitamin D was handled as a categorical variable (quartile, Q1–Q4) (Q4 vs. Q1, OR: 0.82, 95% CI: 0.77 to 0.87, p < .001), and a significant linear trend was observed (p for trend <.001). After analysis, a nonlinear relationship was detected between serum vitamin D and MAFLD, with an inflection point of 2.23 (44.6 nmol/L or 17.84 ng/mL). The effect sizes and the confidence intervals on the left and right sides of the inflection point were 1.16 (1.06 to 1.28) and 0.89 (0.86 to 0.91), respectively. All interactions with MAFLD were not significant for age, sex, diabetes, hypertension, smoking and body mass index (p for interaction = .110, .558, .335, .195, .616 and .401, respectively).

Conclusions

There was a nonlinear relationship between serum vitamin D and MAFLD. When the serum vitamin D level was ≥44.6 nmol/L (17.84 ng/mL), a negative correlation between serum vitamin D and MAFLD was detected. Below this level, serum vitamin D might promote the progression of MAFLD.

Keywords:

• Serum vitamin D
• MAFLD
• association
• nonlinear correlation
• retrospective

Ethics approval and consent of participate

This population-based study complies with ethical guidelines of the Declaration of Helsinki (1975) and was approved by the Ethics Committee of the First Affiliated Hospital of Wenzhou Medical University (ethical code: KY2020-200). The data were anonymous, so the requirement for informed consent was waived (the application for non-informed consent has been approved by the ethics committee).

Acknowledgment

The authors thank the assistance of the First Affiliated Hospital of Wenzhou Medical University in this study.

Author contributions

YQG, YLX and TTW conceptualized this study. YLX, YQG, HS, XCS, YXL, and TTW collected the data. YLX and YQG managed the statistical analysis. YLX, YQG, and TTW analyzed the data. YQG, YLX, and TTW reviewed the results and wrote the original draft. YQG, YLX, TTW, HS, YXL, and XCS revised the manuscript. YQG and YLX contributed to this article equally.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

The datasets generated and/or analysed during the current study are not publicly available due this study is still in progress but are available from the corresponding author on reasonable request.

Additional information

Funding

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.