Asbestos-related disease among sheet metal workers 1986-2004: radiographic changes over time.

BACKGROUND In 1985, the Sheet Metal Workers International Association and the Sheet Metal and Air Conditioning National Association formed The Sheet Metal Occupational Health Institute Trust (SMOHIT) to examine the health hazards of the sheet metal industry. Between 1986 and 2004 18,211 individuals were examined. At the time of the first examination 9.6% of all participants (1,745) had findings consistent with parenchymal disease (ILO > 1/0), and 21% (3,827) had pleural scarring. METHODS 2181-Two thousand hundred eighty-one who had no radiographic evidence of pneumoconiosis on baseline examination underwent a second examination. RESULTS By the second examination, 5.3% had developed parenchymal disease on chest radiograph; an additional 12.4% had developed pleural scarring without parenchymal disease. Factors that predicted new cases of pneumoconiosis on radiograph were the calendar year the worker entered the sheet metal trade, smoking, and shipyard work. Forty-seven percent of those smoking at the time of initial exam reported having quit smoking by the second examination. CONCLUSIONS Asbestosis is still occurring 50 years after first exposure. Exposed workers benefit from medical screening programs that incorporate smoking cessation.