Dietary inflammatory index and its impact on severity and recurrence of Tourette syndrome in children

BACKGROUND Tourette syndrome (TS) is a neurodevelopmental disorder characterized by the presence of motor and vocal tics, typically beginning in childhood. Despite significant research efforts, the exact pathophysiology of TS remains incompletely understood. Recent studies suggest that inflammation may play a role in the severity and progression of TS, pointing to the potential influence of dietary and lifestyle factors on the condition. Currently, research on the specific connection between dietary inflammatory index (DII) and TS is still in its early stages, requiring additional clinical and epidemiological studies to validate the strength and specific mechanisms of this connection. AIM To investigate the association between DII and the severity, recurrence, and inflammatory levels of TS in children. METHODS A total of 207 children diagnosed with TS in the pediatric department of Qingdao Chengyang People’s Hospital from January 2022 to January 2023 were selected. They were divided into stable and unstable groups based on follow-up conditions. Before enrollment, general information of the children [age, gender, body mass index (BMI), guardian’s education level, DII score, medical history, family history, academic stress, electronic device usage, medication, and disease progression] was assessed, and serum inflammatory levels were measured during follow-up visits. DII scores and Yale Global Tic Severity Scale (YGTSS) scores were calculated. Furthermore, based on YGTSS scores, the children were classified into mild, moderate, and severe groups. The DII, interleukin-6 (IL-6), C-reactive protein (CRP), and tumor necrosis factor-alpha (TNF-α) levels in each group were compared. RESULTS Follow-up surveys were completed by 207 children and their guardians. Among them, 117 children were in the stable group, and 90 were in the recurrent group. We found no statistically significant differences in age, gender, comorbidities, BMI, and disease duration between the two groups (P > 0.05). However, academic stress, electronic device usage, medication, guardian’s education level, and DII scores showed statistically significant differences between the groups (P < 0.05). Multifactorial regression analysis revealed that guardian’s anxiety level, DII score, medication, academic stress, and family history were statistically significant factors (P < 0.05) affecting the recurrence of TS in children. Therefore, anxiety level, DII score, medication status, electronic device usage, and academic stress were identified as factors influencing the recurrence of TS in children. Among them, DII score, academic stress, and family history had odds ratios (OR) greater than 1, indicating risk factors, whereas medication status and guardian’s education level had OR values less than 1, indicating protective factors. According to the YGTSS scores, children were categorized into mild, moderate, and severe groups. Comparative analysis of DII and inflammatory levels in children with different degrees of tic disorders revealed that the severe group had the highest DII and inflammatory levels, followed by the moderate group, and the mild group had the lowest levels. The trend of TS progression was consistent with the DII results. Receiver operating characteristic curves were plotted to predict disease progression in patients with TS via inflammatory markers. The areas under the curve for IL-6, CRP, and TNF-α were 0.894 (95%CI: 0.817-0.969), 0.793 (95%CI: 0.694-0.893), and 0.728 (95%CI: 0.614-0.843) respectively, with statistically significant differences (P < 0.05). According to the Youden index, the optimal cutoff values were IL-6 = 3.775 ng/L (sensitivity 68.1% and specificity 68.4%), CRP = 6.650 mg/L (sensitivity 60.6% and specificity 68.4%), and TNF-α = 0.666 (sensitivity 60.6% and specificity 71.1%). CONCLUSION We found a certain correlation between DII and the severity, recurrence, and inflammatory levels of TS in children. Reasonable reduction in the intake of pro-inflammatory foods may be beneficial in reducing the risk of disease progression in children with TS.