Research Links Hypothyroidism with Obstructive Sleep Apnea in São Paulo Study

The research, part of the São Paulo Epidemiological Sleep Study (EPISONO 2018), involved 761 participants from São Paulo who underwent laboratory tests and polysomnography. Hypothyroidism was identified in 12.6% of participants, with nearly half (49.5%) also suffering from OSA. The study, published in May in the journal Sleep, was backed by FAPESP (projects 20/13467-8 and 21/13004-0).

Ellen Maria Sampaio Xerfan, the study’s lead author, noted that while the team expected a significant prevalence of sleep apnea among those with hypothyroidism, the results surpassed expectations. Typical literature reports a prevalence of 30% to 40%, while this study found nearly 50% among participants.

Hypothyroidism, characterized by inadequate thyroid hormone production, commonly results from Hashimoto’s thyroiditis, an autoimmune disorder. Symptoms include fatigue, weight gain, hair loss, and difficulty concentrating, with estimates suggesting that 4% to 8% of the population is affected.

OSA occurs due to repeated interruptions in breathing during sleep, leading to fragmented sleep and a higher risk of cardiovascular and metabolic diseases. Xerfan explained the interplay between thyroid function and sleep, noting both are vital for maintaining bodily homeostasis.

The study revealed that those with hypothyroidism experienced more disrupted sleep and a clearer correlation with OSA severity. The analysis also indicated that poorer sleep quality may increase the risk of developing hypothyroidism, suggesting a complex interaction between the two conditions.

Professor Monica Levy Andersen, the study advisor, emphasized the importance of addressing sleep issues in clinical practice, as they often go unexamined despite their potential impact on overall health.

In addition, the study assessed the effect of hormone replacement therapy, finding that treated participants averaged 49 more minutes of sleep per night and spent 22 additional minutes in deep sleep. Xerfan noted this indicates a positive impact on sleep architecture due to treatment.

Andersen pointed out that while treating hypothyroidism may improve certain sleep metrics, it does not eliminate the necessity for evaluating and treating sleep apnea, as both conditions can independently elevate cardiovascular risks.

Looking forward, the researchers plan to analyze additional data from the EPISONO study to further understand the relationship between sleep apnea interventions and thyroid function. They advocate for early diagnosis and treatment of both conditions to enhance quality of life and mitigate health risks.

The study, titled "1040 sleep traits and obstructive sleep apnea in hypothyroidism: Findings from the EPISONO database," can be accessed at academic.oup.com/sleep/article/49/Supplement_1/A463/8674319.