Gender Differences in the Clinical and Polysomnographic Characteristics Among Australian Aboriginal Patients with Obstructive Sleep Apnea

Abstract

Background

In this study, we assessed the clinical and polysomnographic (PSG) characteristics according to gender among Australian Aboriginal men and woman diagnosed to have obstructive sleep apnea (OSA).

Methods

In this retrospective study, all adult Aboriginal patients over 18 years of age diagnosed to have OSA with an apnea hypopnea index (AHI) > 5/hour over a 5 year period were included.

Results

Of the 337 patients (168 females and 169 males), who underwent a diagnostic PSG, 297 (88%) were diagnosed to have OSA (AHI) >5/hour), 154/297 males (52%) and 143/297 females (48%). Amongst male and female patients with OSA, 63% and 37% were in the severe spectrum (AHI>30/hour). The male cohort had higher stage N1 NREM sleep (P<0.001), reduced N3 NREM sleep (P<0.001), higher AHI severity (P<0.001), higher NREM AHI (P<0.001), and high arousal index (P<0.005). REM sleep-related AHI was higher among female patients with all severity of OSA, along with severe oxygen desaturation during REM sleep. Among patients with severe OSA, the female cohort were younger (age 46 years vs 49 years, P=0.030) and had higher BMI with all severity of OSA, while males had larger neck circumference compared to females. Hypertension increased the odds of severe OSA versus the combined odds of mild and moderate OSA for both genders.

Conclusion

This study highlights some important differences in the way sleep apnea manifests in Australian Aboriginal males and females and further studies are warranted to explore avenues to look for a physiological basis for these observations and targeted interventions.

Keywords:

• aboriginal
• ethnic
• female
• gender
• male
• obstructive sleep apnea

Abbreviations

AF, atrial fibrillation; AHI, apnea hypopnea index; AI, arousal index; TSI, Torres Strait Islander; ATSI, Aboriginal and/or Torres Strait Islander; ASA, Australasian Sleep Association; Avg SpO₂, average oxygen saturation; BMI, body mass index; COPD, chronic obstructive pulmonary disease; CPAP, continuous positive airway pressure; CKD, chronic kidney disease; Circ, circumference; ESS, Epworth sleepiness score; HREC, Human Research Ethics Committees; /h, per hour; NREM, non rapid eye movement; N1, N2, N3, non-rapid eye movement sleep stage; NT, Northern Territory; NATA, National Association of Testing Authorities, Australia; OSA, obstructive sleep apnea; OR, odds ratio; PSG, polysomnography; REM, rapid eye movement; SpO₂, oxygen saturation; TEHS, Top End Health Service; Mins, minutes.

Acknowledgments

We thank the sleep technologist at Darwin Respiratory and Sleep Health for the invaluable contribution towards this study. Institutions where work was performed: Department of Respiratory and Sleep Medicine, Royal Darwin Hospital, Darwin, Northern Territory, Australia and Darwin Respiratory and Sleep Health, Darwin, Northern Territory, Australia, 0810.

Disclosure

Robert Adams reports grants from ResMed Foundation, outside the submitted work. The authors report no other potential conflicts of interest for this work.