Dietary and lifestyle correlates of symptom burden in Hashimoto’s thyroiditis

Introduction: Hashimoto’s thyroiditis (HT) is a chronic autoimmune condition associated with a wide range of physical and psychological symptoms that may negatively affect patients’ well-being. Although lifestyle and dietary factors are believed to influence symptom burden, their role remains unclear. Materials and methods: A cross-sectional study was conducted in 234 Greek adults with HT. All data were collected using an anonymous online survey. HT-related symptoms were assessed using a researcher-developed exploratory symptom checklist, while psychopathological symptoms were evaluated using the Symptom Checklist-90-Revised. Dietary habits were evaluated via a food frequency questionnaire. Self-reported height and weight were used to calculate body mass index (BMI). Results: Mean HT-related symptom score was significantly correlated with the Global Severity Index (GSI), depression, and anxiety (all p < 0.01). Higher BMI was associated with increased mean HT-related symptom score, GSI, and anxiety (all p ≤ 0.01). Regarding dietary factors, potato consumption was associated with higher mean HT-related symptom score, GSI, depression, and anxiety, whereas fruit intake was associated with lower mean HT-related symptom score and alcohol consumption with greater depressive symptoms. In multivariable analysis, mean HT-related symptom score remained independently associated with higher GSI (β = 0.434, p < 0.001) after adjustment for BMI, smoking status, and disease duration. BMI and disease duration emerged as independent positive and negative correlates of GSI, respectively, while smokers had higher GSI than non-smokers. Conclusions: The study identified BMI, smoking, and dietary factors as modifiable correlates of patient-reported outcomes, encouraging future research to explore the causality of these relationships.