A retrospective‐cohort study of occupational exposure to hexavalent chromium

Abstract

A retrospective cohort study was conducted to examine the risk of mortality, cancer, and other adverse health outcomes, at the United States' largest chromate chemicals manufacturing facility in Castle Hayne, North Carolina. This facility, built in 1971, was designed to reduce the high levels of chromium exposure found at most older facilities. Exposure assessment was based on analysis of more than 5,000 personal breathing zone samples collected over a 15-year period. A questionnaire was used to collect relevant occupational, medical, smoking, and other information from current and former employees. Analysis of the cohort's mortality experience found no substantial departures from that expected based on external comparisons, although evidence of a healthy worker effect was observed. Internal cohort analyses were limited by relatively small numbers; however, a subgroup of employees who transferred from older facilities was found to have higher risks of mortality (odds ratio = 1.27 for each 3 years of previous exposure; 90% confidence interval (CI) = 1.07-1.51) and cancer (odds ratio = 1.22 for each 3 years of previous exposure; 90% CI = 1.03-1.45). While this subgroup represented only 11% of the individuals in this study, they accounted for 46% (6/13) of all observed cancers (excluding skin cancers) and 60% (3/5) of lung cancers. There was no increased risk of mortality or cancer among employees who worked only at the newer facility. As an etiologic research study, the results are limited by the relatively small number of subjects and short follow-up; nevertheless, the findings can be used to design and implement a prospective surveillance system for monitoring the health of chromate production workers.

Environmental contaminants as etiologic factors for diabetes.

“…A study of tannery workers occupationally exposed to chromium found a lower prevalence of impaired glucose tolerance and of diabetes mellitus than in the control group, even though the exposed workers were more obese; the results, however, were statistically significant only among workers more than 48 years of age (86). In other studies of chromium-exposed tannery workers, investigators have generally not presented results for diabetes (87,88), although in one study exposed workers had an SMR of 130 (95% CI, 67-227) (89).…”

Chromium

“…121 An etiological research study of 398 chromate workers at a new facility, where Ͻ99% of the personal breathing zone samples were Ͻ50 µg Cr (VI)/m 3 , did not demonstrate increased mortality. 122 The number of subjects was small and the follow-up period was relatively short (15 years). The risk of cancer from dermal or oral exposures to hexavalent chromium compounds is not well documented.…”

Assessment of the mode of action underlying development of rodent small intestinal tumors following oral exposure to hexavalent chromium and relevance to humans

“…, 2005; Pastides et al . , 1994). Moreover, oral exposure to Cr(VI) is unlikely to pose a risk for lung cancer, as oral exposure to Cr(VI) has not been reported to increase chromium lung burdens (Coogan et al .…”