Associations between unsaturated fatty acids intake and Hashimoto's thyroiditis, Results from NHANES 2007-2012

Purpose Hashimoto's thyroiditis (HT), a prevalent autoimmune disorder, primarily targets the thyroid gland. The influence of dietary factors, particularly unsaturated fatty acids, on HT remains underexplored. This study investigates the association between unsaturated fatty acids and HT prevalence using data from the National Health and Nutrition Examination Survey (NHANES) 2007-2012. Methods A cross-sectional study involving 6944 participants (mean age 49.73 ± 17.71 years) was conducted. Demographic, lifestyle, dietary, and urinary characteristics were assessed. Logistic regression models were employed to control for potential confounders and to estimate odds ratios (ORs) with 95% confidence intervals (CIs) for the association between unsaturated fatty acids and HT. Results The overall prevalence of HT was 11.82%. Individuals with HT were more likely to be older, female, married, non-smokers, drinkers, and have higher income. Dietary intakes of carbohydrates, sodium, energy, protein, polyunsaturated fatty acids (PUFAs), and monounsaturated fatty acids (MUFAs) were significantly lower in the HT group. Additionally, urinary cadmium concentrations were reduced in this group. After adjustments, higher intakes of PUFAs (OR 0.62, 95% CI 0.42-0.89) and a higher ratio of MUFAs to total fatty acids (OR 0.67, 95% CI 0.50-0.90) were associated with a lower risk of HT. Subgroup analyses indicated that these associations were particularly evident among females, individuals under 40 years of age, non-smokers, and alcohol consumers. A restricted cubic spline (RCS) model revealed a nonlinear relationship between PUFAs and HT (P-overall < 0.001, P-non-linear = 0.0127). Sensitivity analyses confirmed the robustness of these findings. Conclusion This study demonstrates that higher intake of unsaturated fatty acids, especially PUFAs and MUFAs, is associated with a reduced risk of HT. The identified nonlinear relationship between PUFAs and HT highlights the complex interplay of dietary factors in autoimmune thyroid diseases. Further research is warranted to elucidate the underlying mechanisms of these associations.