Obstructive Sleep Apnea Heritable but Daytime Sleepiness Influenced by Environment

Obstructive sleep apnea (OSA) and the indices of OSA severity, such as apnea hypopnea index (AHI), respiratory disturbance index, and oxygen desaturation index are heritable whereas daytime sleepiness is mostly influenced by environmental factors, according to study results published in Respiratory Research.¹

OSA is a common disorder that is associated with excessive daily sleepiness, cognitive dysfunction, and increased cardiovascular morbidity and mortality.¹ Previous studies have suggested a possible genetic influence,^2-4 however, the results have not been confirmed. Therefore, researchers evaluated 71 Hungarian twin pairs who were involved in the Hungarian Twin registry (48 monozygotic and 23 dizygotic pairs; mean age, 51 years) and who underwent overnight polysomnography.¹

In this study population, the prevalence of OSA was 41%, and the heritability of AHI, oxygen desaturation index, and respiratory disturbance index ranged between 69% and 83%. They also found that OSA, defined by an AHI ≥5 events/h, was itself 73% heritable. The rest of the variance between 17% and 31% was explained by the unshared environmental component. Daytime sleepiness was mostly influenced by environmental factors, and the variance was influenced 34% by additive genetic factors.

The researchers noted that their study was the first to investigate the heritability of OSA using objective polysomnography. “These observations provide important insights into the pathogenesis and potential treatment of OSA and stimulate further epigenetic studies to understand interconnections between pathophysiology of sleep and metabolic diseases, including obesity,” they concluded.

Future studies are needed to further determine whether close relatives of patients with OSA should receive early family risk-based screening.

References

1. Szily M, Tarnoki AD, Tarnoki DL, et al. Genetic influences on the onset of obstructive sleep apnoea and daytime sleepiness: a twin study. Respir Res. 2019;20:125.
2. Patel SR, Frame JM, Larkin EK, Redline S. Heritability of upper airway dimensions derived using acoustic pharyngometry. Eur Respir J. 2008;32:1304-1308.
3. Patel SR, Larkin EK, Redline S. Shared genetic basis for obstructive sleep apnea and adiposity measures. Int J Obes (Lond). 2008;32:795-800.
4. Desai AV, Cherkas LF, Spector TD, Williams AJ. Genetic influences in self-reported symptoms of obstructive sleep apnoea and restless legs: a twin study. Twin Res. 2004;7:589-595.