Obstructive sleep apnea (OSA) among public-transportation drivers becomes a social concern in a certain number of traffic accidents. Major risk factors of OSA were reportedly obesity and ageing; however, age stratified relationship between OSA and risk factors have yet to be evaluated. This study aimed to evaluate the association between OSA and obesity stratified by age-groups.Methods
One hundred and fifty-five bus drivers were screened by the flow sensor method, to detect subject with a respiratory disturbance index (RDI) more than 15. Then, portable polysomnography (PSG) tests were performed to measure an apnea hypopnea Index (AHI): subjects with AHI≥40 were diagnosed as OSA; for those with 20≤AHI<40 full PSG tests were performed. Portable PSG AHI≥20 was diagnosed as OSA. Relationship between OSA and BMI were statistically compared in three age-groups; younger than 40, 40 to 49, and 50 and older by the logistic regression analysis and unpaired t-test.Result
Of the 152 subjects (45.2±9.3 year-old, BMI 24.5±4.5) after excluding 4 subjects (unexamined by PSG), 55 subjects showed RDI>15 by the screening test and underwent PSG. 25 subjects were diagnosed as a definite OSA. BMI was significantly associated with OSA with OR of 1.17 (95% CI: 1.06 to 1.29). ORs for OSA become greater as the age increased showing greatest OR in 50 and older (OR 5.15, 95% CI: 1.17 to 22.8). Mean BMI of OSA subjects with younger than 40 was greater than that of non-OSA (BMI 34.8±9.3 and 23.1±5.2, respectively, p=0.0012), however, no difference was found in those with 40–49 and 50 and older.Discussion
The result suggests weight reduction may more effective for younger drivers. Obesity of the drivers is highly associated with OSA for younger than 40, while ageing is more correlated with OSA than obesity for 50 and older.