Conscientiousness personality is associated with increased thyroid nodule risk and sleep quality plays a masking role in this association.

This study aimed to investigate the correlation between the Big Five Personality Traits and the occurrence of thyroid nodules (TNs), so as to provide evidence for individualized treatment from the perspective of personality and raise public awareness about thyroid health. A total of 331 participants who underwent physical examinations and thyroid ultrasound at the Health Management Center of the First Affiliated Hospital of Jinzhou Medical University were included in this survey and completed a panel of questionnaires including a general demographic questionnaire, the NEO Five-Factor Inventory (NEO-FFI), and the Pittsburgh Sleep Quality Index (PSQI). Among the 331 subjects, 42.9% (142/331) had TNs, 72.51% (240/331) were female, and 70.69% (234/331) were younger than 45 years old. There were statistically significant differences between the TNs group and the non-TNs group in terms of gender, age, age group, education, occupation, conscientiousness, smoking status, sleep disturbances, daytime dysfunction, total PSQI score, hyperlipidemia, hypertension and blood glucose (all Ps < 0.05). Logistic regression showed that conscientiousness was positively correlated with the occurrence of TNs in people under 45 years old (P < 0.05). Mediating effect analysis indicated that sleep quality had a masking effect between conscientiousness and the occurrence of TNs. Conscientiousness increases the risk of TNs, and sleep quality plays a masking role in the influence of conscientiousness on the occurrence of TNs among adults aged < 45 years old.