Stroke among male professional drivers in Denmark, 1994–2003

Abstract

Objectives: (1) To estimate the relative risk of stroke among various groups of professional drivers; (2) to determine if any excess risk should be attributed to infarction or haemorrhage; (3) to estimate the relative risk ratio for stroke among professional drivers living in Greater Copenhagen compared to those living outside the metropolis.

Methods: A cohort of 6285 bus drivers, 4204 car, taxi, and van drivers, and 25 879 heavy truck and lorry drivers were followed up for hospital admission due to stroke and sub-diagnoses in the period 1994–2003. Using hospital admission for all economically active men as the standard, the standardised hospitalisation ratios (SHR) were calculated, taking age and county into consideration.

Results: There was a high SHR for stroke among all groups of professional drivers (SHR = 132; 95% CI 121–141). Among car, taxi, and van drivers the SHR was 157 (95% CI 132–189), among bus drivers it was 139 (95% CI 119–163), and among heavy truck and lorry drivers it was 124 (95% CI 113–136). The excess risk for all groups of professional drivers was highest for cerebrovascular infarction (SHR = 139; 95% CI 124–155) and lowest for non-traumatic intracranial haemorrhage (SHR = 113; 95% CI 96–133). The excess risks for all groups were significantly higher for cerebrovascular infarction than for non-traumatic intracranial haemorrhage (relative risk ratio (RRR) 1.23; 95% CI 1.01–1.51). The RRR of stroke among drivers in the metropolitan area compared to rural areas was 1.13 (95% CI 0.94–1.36). The RRR for stroke among car, taxi, and van drivers compared to drivers of heavy trucks and of lorries was 1.28 (95% CI 1.03–1.57).

Conclusion: All groups of professional drivers are at increased risk of stroke. The excess risk is more due to cerebral infarctions than to non-traumatic intracranial haemorrhage. The risk of stroke is higher among drivers carrying passengers than among drivers carrying goods.