Greater exposure to metalworking fluids (MWF), which are used to cool and lubricate metal in occupational settings, may increase the risk of renal cell carcinoma (RCC), especially among white men, researchers found.
A team led by Katie M. Applebaum, ScD, of George Washington University in Washington, DC, studied a prospective cohort of 33,421 Michigan autoworkers (27,148 white, 6273 black, 28,908 men, 4513 women) who were followed up from 1985 to 2009. During the follow-up period, 135 RCC cases occurred: 114 among whites and 21 among blacks.
White men with a mean and median cumulative MWF exposure of 18.80 and 9.60 mg/m3 per year had a significant 11% and 6% increased risk of RCC, respectively, according to a paper published online in Occupational and Environmental Medicine. The small number of exposed cases among black men and among women provided limited statistical power for estimating RCC risk associated with MWF exposure, the investigators noted.
The individuals in the study were part of the United Autoworkers-General Motors cohort, which is unique because it is a large cohort followed for decades with quantitative exposure estimates for each of the 3 main types of MWF, Dr Applebaum and her colleagues stated. These types are straight (mineral oils), soluble (a mixture of mineral oil and water), and synthetic (water-based, no oil).
The investigators noted that the International Agency for Research on Cancer classified mineral oils as a human carcinogen in 1984, based on previous research showing a link to cancers of the skin, stomach, rectum, bladder, larynx, and pancreas.