Low serum 25 hydroxyvitamin D Is associated with severe metabolic dysfunction-associated steatotic liver disease in individuals with overweight/obesity: A cross-sectional study

The role of vitamin D status in metabolic dysfunction-associated steatotic liver disease (MASLD) remains controversial. Furthermore, research evaluating the relationship between vitamin D status and abdominal fat distribution is limited. Therefore, we hypothesized that serum vitamin D is inversely associated with the severity of liver fat content (LFC) in populations with overweight/obesity. A total of 201 subjects with body mass index ≥23 kg/m² were classified by 25 hydroxyvitamin D (25 (OH) D) concentration as either vitamin D deficiency (<20 ng/mL) or vitamin D normal (≥20 ng/mL). Magnetic resonance imaging-proton density fat fraction was used to measure fat accumulation in the liver, pancreas, and abdomen subcutaneous and visceral. The LFC and subcutaneous adipose tissue (SAT) were significantly higher in the vitamin D deficient group compared to the normal vitamin D group (P < .05). However, there were no significant differences in visceral adipose tissue or pancreatic fat content between the 2 groups. Additionally, as the severity of LFC and SAT increases in individuals with overweight/obesity, serum 25 (OH) D concentration significantly decreases (P < .05). Further multivariate-adjusted logistic regression analysis revealed that individuals in the highest tertile of 25 (OH) D exposure exhibited lower risks of severe hepatic steatosis compared to those in the lowest tertile (T3 vs. T1, OR 0.26, 95% CI 0.10-0.67, P = .01). Our results identify a significant inverse association between serum 25 (OH) D concentration and severe MASLD in individuals with overweight/obesity. Further research is needed to explore the metabolic mechanisms underlying this association and their implications for liver protection.