Abstract: Objective To explore the combined therapeutic effects of vitamin D and probiotics on nonalcoholic fatty liver disease (NAFLD) in pediatric obesity.Methods 105 obese children diagnosed with NAFLD were enrolled from our hospital and were randomized into three groups (35 cases each) using a stratified random number table. The control group underwent nutritional and lifestyle interventions. In addition to the control goup`s interventions, Group A was administered probiotics, while Group B was given both vitamin D and probiotics. The changes of body mass index (BMI), liver function metrics, glucose and lipid metabolismmarkers, insulin resistance index (HOMA-IR), and inflammatory cytokines levels amont the three groups before and after the intervention were compared.Results After the intervention, there was a notable reduction in the levels of BMI, AST, and ALT across all three groups compared to their pre-intervention levels (P<0.05). On comparing between groups, BMI measurements in Group A and B were statistically comparable (P>0.05), yet both displayed significantly reductions when contrasted with the control group (P<0.05); The levels of AST and ALT in Group B were reduced compared to both Group A and the control group (P<0.05). Post-intevention levels of HOMA-IR, TC, and TG in the three groups also significantly decreased compared to their initial values(P<0.05). An intergroup analysis revealved that the levels of HOMA-IR, TC, and TG in Group B were substantially lower than in Group A, with the difference being statistically significant (P<0.05). In group B, post-intervetion 25 (OH) D3 levels significantly surged, while TNF- α and IL-6 levels saw a considerable decline(P<0.05). Conversly, in both Group A and the control group, no significant fluctuations were obderved in the levels of 25 (OH) D3, TNF- α and IL-6 before and after the intervention(P>0.05). After the intervention, the rates of intestinal microbiota dysbiosis in Group A and B reduced to 45.71% and 37.14% respectively, showing a significant decline from their pre-intervention values of 85.71% and 80.00% (P<0.05). In conreast, the control group′s dysbiosis rate showed no significant alteration, remaining relatively stable at 74.29% pre-intervention and 71.43% post-intervention(P>0.05). The post-intervention imbalance rates of intestinal microbiota were conparable between Group A and Group B(45.71% vs 37.14%, P>0.05). When evaluating the overall treatment efficacy, Group B exhibited the highest rate at 94.29%, followed by Group A at 80.00%, and the Control Group lagging behing at 60.00%. The differences in effective rates between the groups were statistically significant(P<0.05).Conclusion Incorporating probiotics and vitamin D into lifestyle interventions for obese children with NAFLD has been shown to effectively improve their glucose and lipid metabolism, diminish insulin resistance, lower inflammatory cytokine levels, and ameliorate liver function.

Key words: Non-alcoholic fatty liver disease, Obesity, Children, Vitamin D, probiotics, insulin resistance