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Published: 31 July 2009

Authors: Mihaere, K., Harris, R., Gander, P., Reid, P., Purdie, G., Robson, B., et al.

Study Objectives: Examine the distribution of symptoms and risk factors, and estimate the prevalence of obstructive sleep apnea (OSA) among Māori and non-Māori New Zealanders.
Design: Mail-out survey to a stratified random sample from the electoral roll of 10,000 people aged 30-59 y, and overnight MESAM IV monitoring during sleep of a similarly aged stratified random sample of 364 people from the Wellington electoral roll.
Setting: Nationwide survey of OSA symptoms (71% response rate) and regional home-based measurement of respiratory disturbance index (RDI, 4% oxygen desaturations/h of sleep, plus bursts of snoring or ≥ 10/min increase in heart rate).
Participants: Sample designs aimed for equal numbers of Māori and non-Māori participants, men and women, and participants in each decade of age.
Interventions: N/A
Measurements and results: Māori were more likely than non-Māori to report OSAS risk factors and symptoms. After controlling for sex and age, Māoriwere 4.3 times more likely to have RDI ≥ 15 (95% CI = 1.3–13.9). Ethnicity was not an independent risk factor after controlling for body mass index (BMI) and neck circumference. The prevalence of OSAS (RDI ≥ 5 and ESS > 10) was conservatively estimated to be 4.4% for Māori men, 4.1% for non-Māori men, 2.0% for Māori women, and 0.7% for non-Māori women.
Conclusions: The national survey and the regional monitoring study indicate a higher prevalence of OSA among Māori and among men. The higher prevalence among Māori appears to be attributable to recognized risk factors, notably body habitus. In addition to increased prevention and treatment services, strategies are needed to reduce ethnic disparities in OSAS prevalence.