The study subjects consisted of 365 bus drivers and 1214 taxi drivers in Hanoi, Vietnam. Face-to-face interviews were …The 365 bus drivers were all male and recruited from five bus companies in Hanoi. Three quarters of the bus drivers … were less than 45 years old. The mean age of the bus drivers was 39.2 (SD: 7.2) years old. The mean working years as bus …