Subtype-specific causal effects of hypothyroidism on obstructive sleep apnea: A bidirectional Mendelian randomization...

Area of Science:

• Endocrinology
• Sleep Medicine
• Genetics

Background:

• Hypothyroidism (HT) and obstructive sleep apnea (OSA) are common conditions with potential shared underlying factors.
• Previous research suggests a link between HT and OSA, but causal relationships and subtype-specific effects remain unclear.

Purpose of the Study:

• To investigate the bidirectional, subtype-specific causal relationships between various forms of hypothyroidism and obstructive sleep apnea.
• To utilize a robust Mendelian randomization design to infer causality from observational data.

Main Methods:

• A two-sample Mendelian randomization (MR) design was employed using genome-wide association study (GWAS) summary statistics from European populations.
• Primary analysis used the inverse variance weighted (IVW) method, with MR-Egger, weighted median, and sensitivity analyses to assess robustness and pleiotropy.
• Bidirectional MR analyses were conducted to examine causal effects in both directions between hypothyroidism subtypes and OSA.

Main Results:

• Specific hypothyroidism subtypes, including autoimmune and congenital iodine deficiency syndromes, were causally associated with an increased risk of OSA.
• Thyroglobulin showed a protective causal effect against OSA.
• Genetically predicted OSA causally increased the risk of certain hypothyroidism types, indicating a bidirectional relationship.

Conclusions:

• This study establishes subtype-specific and bidirectional causal associations between hypothyroidism and obstructive sleep apnea.
• Findings underscore the importance of considering thyroid dysfunction in OSA management and vice versa.
• Personalized screening and management strategies are recommended for patients with diverse forms of thyroid dysfunction and OSA.