Abstract
The association between obstructive sleep apnea (OSA) and increased cardiometabolic risk (CMR) has been well documented in higher-income countries. However, OSA and its association with CMR have not yet been investigated, based on objective measures, in Southern Africa. We measured polysomnography (PSG)-derived sleep characteristics, OSA prevalence and its association with cardiometabolic diseases in a rural, low-income, aging African-ancestry sample in South Africa.
Seventy-five participants were recruited. BMI, hypertension, diabetes, dyslipidaemia, and HIV status were determined. A continuous CMR score was calculated using waist circumference (WC), random glucose, HDL-cholesterol, triglycerides, and mean arterial blood pressure. Sleep architecture, arousal index, and apnea-hypopnea index (AHI) for detection of OSA (AHI≥15) were assessed by home-based PSG. Associations between CMR score and age, sex, socio-economic status (SES), AHI and TST were investigated by multivariable analysis.
In our sample (53 women, 66.1±10.7y, 12 HIV+), 60.7% were overweight/obese, 61.3% hypertensive and 29.3% had undiagnosed OSA. Being older (p=0.02), having a greater BMI (p=0.02) and higher WC (p<0.01) were associated with OSA. AHI severity (ß=0.011p=0.01) and being a woman (ß=0.369, p=0.01) were independently associated with a greater CMR score in SES- and age-adjusted analyses.
In this aging South African community with obesity and hypertension, OSA prevalence is alarming and associated with CMR. We demonstrate feasibility of detecting OSA in a rural setting using PSG. Our results highlight the necessity for actively promoting health education and systematic screening and treatment of OSA in this population, to prevent future cardiovascular morbidity, especially among women.