Vasospastic tendency and Raynaud's phenomenon in smelter workers exposed to arsenic

The long-term drinking of water with a high content of inorganic arsenic can lead to Raynaud's phenomenon, acrocyanosis, and gangrene of the lower legs ("black foot disease"). We have measured the systolic blood pressure in the finger after local cooling in 47 workers from a copper smelter who were habitually exposed to moderate amounts of arsenic dust. The controls were 48 workers not exposed to arsenic. The concentration of inorganic arsenic including its metabolites in urine was determined. We found a difference between As-exposed workers and the controls in the finger systolic pressure at skin temperatures of 10 degrees C and/or 15 degrees C expressed as a percentage of the pressure at 30 degrees C (FSP%), P less than 0.01; and the prevalence of Raynaud's phenomenon, P less than 0.05. A low FSP% was taken to indicate vasospastic tendency. There was a covariation between the duration of exposure to arsenic and the decrease in finger systolic pressure between the measurements at 30 and 10 degrees C (P less than 0.05). The uptake of arsenic at the time of the study probably did not exceed 300 micrograms/day. This was confirmed by estimation of the urinary excretion. The average total arsenic uptake was estimated to be about 4 g over 23 years, which is less than the total uptake of 20 g of arsenic by subjects who developed black foot disease. Increased vasospastic reactivity in the fingers and Raynaud's phenomenon in smelter workers seems to be due to functional alterations in the vessels caused by inhalation of arsenic.