Production of silicon metal and alloys is associated with accelerated decline in lung function: a 5-year prospective study among 3924 employees in norwegian smelters.

Objectives: To investigate the association between decline in lung function and production of alloys in the Norwegian smelting industry.

Methods: All employees (N = 3924) were examined annually for 5 years (16,570 examinations). The employees were classified into three categories: 1) line operators (employed full time in the production line), 2) nonexposed (no exposure last year), and 3) non-line operators (remaining subjects). The outcome variable was expressed as forced expiratory volume in 1 second per squared height (FEV1/height(2)).

Results: In the subcohorts of the ferrosilicon/silicon metal and silicon carbide industries, the differences between line operators and nonexposed workers were -2.3 (-4.3 to -0.3) (CI = 95%) and -5.6 (-10.4 to -0.7) mL/(m(2) x year), respectively.

Conclusion: Line operators in the ferrosilicon/silicon metal and silicon carbide industries had a steeper annual decline in FEV1/height compared with nonexposed workers.