Nazanin Pourseyedi
, Sara Arefhosseini, Helda Tutunchi
, Saeed Ostadrahimi, Mehrangiz Ebrahimi-Mameghani
*
Abstract
Background: While evidence suggests a link between serum vitamin D levels and hypothyroidism, this relationship remains unclear, particularly within non-autoimmune hypothyroid conditions. This study aimed to investigate the association between vitamin D deficiency (VDD) and non-autoimmune hypothyroidism in overweight/obese patients with non-alcoholic fatty liver disease (NAFLD). Methods: This case-control study included 154 overweight or obese (body mass index [BMI]≥25 kg/m2) female adults diagnosed with NAFLD based on ultrasonography findings. Seventy-seven patients with NAFLD and VDD (serum 25(OH)D concentration ≤30 nmol/L) as the “Case” group and Seventy-seven age, and BMI-matched patients with NAFLD without VDD as the “Control” group were enrolled. Anthropometric parameters and serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), free triiodothyronine (FT3), free thyroxine (FT4) and thyroid stimulating hormone (TSH) were measured. Results: The baseline characteristics of the study showed no significant differences in age, anthropometric measures, or physical activity levels between the two groups. Analysis of weekly frequency consumption of vitamin D-rich foods revealed no notable differences between VDD cases and controls, except for a statistically significant difference in the consumption of low-fat cheese (p=0.024). Additionally, no significant association was identified between TSH levels and VDD in either crude or adjusted models, after accounting for potential confounders, including sun exposure duration, BMI, and serum ALT and AST levels. However, participants with low sun exposure (≤1 hour/day) were significantly more likely to have VDD (OR=3.62; 95% CI=1.52-8.60). Conclusion: Our results did not show association between serum vitamin D levels and non-autoimmune hypothyroidism in patients with NAFLD.