Prevalence and risk factors for obstructive sleep apnoea in Dar es Salaam, Tanzania

Background: Obstructive sleep apnoea (OSA) is a common cause of daytime sleepiness, a condition associated with accidents, antisocial behaviour, mood disturbances, cognitive dysfunctions and inefficiency at work. This study was carried out to determine the prevalence and risk factors for obstructive sleep apnoea in Dar es Salaam, Tanzania.
Methods: Multistage random sampling of households was done. Eligible members were interviewed and underwent anthropometric measurements. Epworth sleepiness scale was used to asses one’s likelihood of daytime sleepiness. OSA was defined as the presence of 2 of the following: symptoms of obstructive sleep apnoea, a Body Mass Index (BMI) ≥ 28 kg/ m² and a total Epworth score≥ 15.
Results: A total of 1249 people were involved in the study. Of these, 65.2% were females. Night snoring was reported by 9.3% of the respondents. The prevalence of OSA was 11.5% (144/1249). OSA was significantly more common among females (12.9%) (p = 0.038) than males. OSA prevalence increased significantly with increasing age (p <0.001) and increasing BMI (p- value < 0.001). Respondents with hypertension, central obesity and those who snored at night significantly presented with high prevalence of OSA, being 26.5%, 34% and 29.3%, respectively (p- value <0.001 for each). OSA was found in 26.3% of diabetics (p= 0.042). The odds of OSA were significantly higher among females, OR (95% CI) = 2.0 (1.2-3.2), among age group 45-54 years, OR (95% CI) = 2.2 (1.1-4.3), among those with central obesity OR (95% CI) = 3.4 (2.1- 5.4) and among night snorers OR (95% CI) = 2.8(1.7-4.6). Socio-economic status, cigarette smoking, alcohol consumption, hypertension and diabetes mellitus could not predict OSA.
Conclusions: OSA is prevalent among residents of Dar es Salaam and significantly associated with age 45 years or older, female gender, high socioeconomic status, obesity and overweight and night snoring. Predictors of OSA were female gender, age above 45 years, central obesity, and night snoring. Clinicians should therefore actively look for OSA in patients with these characteristics.

Keywords
sleep apnoea; obstructive; risk factors; prevalence; polysomnography; Tanzania