Elevated serum liver enzymes and fatty liver changes associated with long driving among taxi drivers.
Lippmann-SJ; Richardson-DB; Chen-J-C
Am J Ind Med 2011 Aug; 54(8):618-627
Background: Previous studies suggested increased morbidities and mortalities of liver diseases in drivers. Methods:To examine whether driving (monthly driving distance; tenure) is associated with elevated alanine aminotransferase (ALT), aspartate aminotransferase (AST), or chronic fatty liver (FL) changes, we performed a cross-sectional, secondary analysis of the Taxi Drivers' Health Study (n equals 1,355), adjusting for clinical, demographic, and lifestyle factors. Results: Prevalence of elevated ALT, elevated AST, and fatty liver changes were 22.0 percent, 5.1 percent, and 9.3 percent, respectively. Driving distance had a positive association with elevated ALT with a prevalence ratio of 1.35 (95 percent CI: 0.98, 1.89) comparing the highest versus lowest driving quartile. This association differed by alcohol use, with a corresponding prevalence ratio of 2.08 (95 percent CI: 1.30, 3.33) among ''past/current'' drinkers but no association among ''never'' drinkers. Similar patterns were found for AST, but estimates were less stable. We found a curvilinear response pattern for fatty liver changes; prevalence first increased with years as a taxi driver and then receded in the highest ranges of driving tenure, regardless of the alcohol history. Conclusions: Our results provide evidence that long driving is associated with both short-term and chronic liver insults, although alcohol use appears to modify this putative effect.
Service-industries; Drivers; Transportation; Transportation-industry; Transportation-workers; Liver-disorders; Enzyme-activity; Enzymes; Liver-enzymes; Fatty-acids; Amino-acids; Demographic-characteristics; Alcoholic-beverages; Work-intervals; Liver-damage;
Author Keywords: fatty liver disease; professional driving; occupational epidemiology; taxi drivers; alanine aminotransferase
Steven J. Lippmann, MSPH, Department of Epidemiology, CB#7435, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, NC 27599
American Journal of Industrial Medicine
University of North Carolina, Chapel Hill, North Carolina