Sleep patterns, depression, and incident thyroid diseases: a large cohort study of 371,627 United Kingdom biobank participants

Sleep patterns and depression are increasingly linked to endocrine health, yet their associations with thyroid diseases remain underexplored. This study aimed to investigate the prospective relationships between sleep patterns, depressive symptoms, and incident thyroid diseases in a large cohort. Utilizing data from 371,627 United Kingdom Biobank participants, sleep patterns were categorized as healthy, moderate, or poor based on five behaviors: duration, chronotype, insomnia, snoring, and napping. Depressive symptoms were assessed using the PHQ-2 questionnaire. Thyroid diseases (hyperthyroidism, hypothyroidism, goiter, thyroiditis) were identified via ICD codes. Cox proportional hazards models evaluated associations, adjusting for demographics, lifestyle, and clinical covariates. Additive and multiplicative interactions between sleep patterns and depression were examined. Over a median 13.7-year follow-up, 15,609 participants developed thyroid diseases. Compared to the poor sleep patterns, moderate (HR = 0.84, 95% CI: 0.78–0.90) and healthy sleep patterns (HR = 0.77, 95% CI: 0.72–0.83) were associated with a significantly lower hazard of thyroid diseases. Healthier sleep patterns were linked to a reduced hazard of hypothyroidism and goiter, while associations with hyperthyroidism and thyroiditis were nonsignificant. Participants with depressive symptoms showed a higher hazard of thyroid diseases (HR = 0.74 for non-depressed, 95%CI: 0.69–0.78). Joint analysis revealed the lowest hazard in non-depressed participants with healthy sleep (HR = 0.59, 95%CI: 0.50–0.70). Sensitivity analyses confirmed robustness across subgroups. Healthier sleep patterns are independently associated with reduced thyroid diseases incidence, particularly hypothyroidism and goiter. Depression exacerbates risk and has a joint effect with sleep pattern on total thyroid diseases. Future longitudinal or interventional studies are needed to determine whether a causal link exits and explore potential preventive strategies.