1019 From Hormones to the Bed: Does Thyroid Function Modulate Sexual and Sleep Health in Men from the Cross-Sectional EPISONO Cohort?

Abstract Introduction Erectile dysfunction (ED) and sleep disturbances are highly prevalent conditions that share neuroendocrine, metabolic, and autonomic pathways. Evidence suggests bidirectional interactions between thyroid function, sleep physiology, and sexual health. This study investigated whether thyroid hormones interact with ED status to influence objective sleep parameters in adult men. Methods This cross-sectional study used data from the 4th edition of the São Paulo Epidemiological Sleep Study (EPISONO), conducted in 2018, which included 769 adults (317 men). After excluding individuals who reported the use of sleep-related medications (benzodiazepines, Z-drugs, melatonin), thyroid medications, or tadalafil, as well as those without essential hormonal or sleep data, the final sample comprised 286 men (230 without ED; 56 with ED). ED status was defined by self-report. All participants underwent full-night polysomnography and morning fasting blood collection for hormonal assessment of thyroid-stimulating hormone (TSH), free thyroxine (FT4), total thyroxine (T4), and total triiodothyronine (T3). Generalized Linear Models adjusted for age and body mass index (BMI) compared hormonal and sleep outcomes between ED groups. Interaction effects between ED and thyroid hormones (TSH, FT4) on sleep outcomes were evaluated using moderation models. Results No significant differences were observed between groups for TSH, T4, FT4, or T3. Men with ED showed a markedly altered sleep architecture, with a lower percentage of N3 sleep. This reduction remained significant after adjusting for age, BMI, or both. Moderation models indicated that ED interacted with TSH to predict total sleep time, wake after sleep onset (WASO), N1%, N2%, N3%, and arousal index. Similar interactions were identified for FT4, influencing wake time, WASO, sleep efficiency, and N2%. Conclusion ED was associated with poorer objective sleep quality, particularly reduced N3%, independent of age and BMI. Thyroid hormones amplified the influence of ED on several sleep parameters, indicating a synergistic effect between ED status and thyroid function on sleep physiology. These findings support an integrated relationship between sexual health, thyroid regulation, and sleep architecture. Support (if any) Associação Fundo de Incentivo à Pesquisa (AFIP), Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), and Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP).