HEALTH STATUS OF GASOLINE STATION WORKERS IN PATHUMWAN AREA, BANGKOK, THAILAND, IN 2004 AND 2009

This research characterized and compared health status of male gasoline station workers in Pathumwan District, Bangkok, in 2004 and 2009. Between these years, use of methyl tert-butyl ether (MTBE) in gasoline was banned in Thailand, and use of gasohol increased. Cross-sectional studies were conducted in each year. Each study included an interview for symptom prevalences, hematological tests and blood biochemical tests for kidney and liver function. Data were analyzed with multiple logistic regression for dichotomous outcomes and multiple linear regression for continuous outcomes. Independent variables included year of study, demographic characteristics, smoking, alcohol drinking, and duration of working at the gas station. Adjusted prevalence of abnormal red blood cell morphology decreased statistically significantly from 2004 to 2009 (modeled odds ratio for 2009 vs. 2004 = 0,34, p=0.04). Adjusted blood alkaline phosphatase level also decreased significantly (modeled decrease = -29.3 units/liter, p<0.001). These findings could plausibly be linked to removal of MTBE. Other health-related metrics did not differ significantly between 2004 and 2009. On balance, there was a limited tendency toward improvement of workers' health from 2004 to 2009. This could be attributable in part to removal of MTBE in gasoline. Further research, perhaps employing additional health metrics, is needed to fully characterize human health effects of MTBE exposure.