Cardiac Damage Secondary to Occupational Exposure to Tin Vapor

Abstract

Tin is commonly used as a coating on copper kitchen appliances, and “tinsmithing” as a trade is common in many non-Western countries, where cooking utensils are re-tinned when the cooking surface wears thin. Tinsmiths, or “tinkers,” are commonly exposed to the following fumes during their work: stannic [tin(IV)] oxide, ammonium chloride, and hydrochloric acid. In this study we assessed workers from tinsmith workshops of our province for signs, symptoms, and laboratory evidence of cardiac end-organ damage. Between June 2002 and March 2003, researchers went to the main tinsmith workshop area of our province to interview tinsmiths in their workplaces and to gather addresses of their “traveling tinker” colleagues, who work with portable equipment. All workers were interviewed and underwent a complete physical examination, blood testing for lipid parameters, and echocardiography. Twenty-six tin workers (mean age 49± 10 y) and 25 control patients (convenience sample of hospital employees) were included in the study. Tobacco use, incidence of hypertension, and serum lipid parameters were not significantly different between the two groups (p < .05). The differences in myocardial performance index, systolic function, and mitral flow A velocity were also nonsignificant. However, the mitral inflow E velocity in the tinsmiths was significantly less than in controls (0.71± 0.1 vs. 0.95± 0.1 m/s, p < .001). The mitral deceleration time was also much longer in the tinsmith group (216± 71 ms vs. 143± 14 ms, p < .001). Eleven of the tinkers (23%) were found to have aortic valve sclerosis (severe in one, moderate in another, mild in the other nine), but aortic valve sclerosis was found in none of the control subjects. One tinsmith was found to have three-vessel coronary disease on angiogram. Another tinker with “myocarditis” in the past, and slow flow on angiography, had normalization of his cardiac tests after refraining from tin exposure for 6 mo. Thus, occupational exposure to heavy tin fumes is associated with left ventricle diastolic dysfunction and sclerosis of the aortic valve. Tin workers should minimize their exposure to tin fumes, and physicians should monitor tinsmiths closely for signs of heart disease.