Lung cancer mortality in nickel/chromium platers, 1946-95.

OBJECTIVES: To investigate mortality from lung cancer in nickel/chromium platers. METHODS: The mortality experience of a cohort of 1762 chrome workers (812 men, 950 women) from a large electroplating and light engineering plant in the Midlands, United Kingdom, was investigated for the period 1946-95. All subjects were first employed in chrome work at the plant during the period 1946-75, and had at least six months employment in jobs associated with exposure to chromic acid mist (hexavalent chromium). Detailed job histories were abstracted from original company personnel records and individual cumulative durations of employment in three types of chrome work were derived as time dependent variables (chrome bath work, other chrome work, any chrome work). Two analytical approaches were used--indirect standardisation and Poisson regression. RESULTS: Based on mortalities for the general population of England and Wales, male workers with some period of chrome bath work had higher lung cancer mortalities (observed deaths 40, expected deaths 25.41, standardised mortality ratio (SMR) 157, 95% confidence interval (95% CI) 113 to 214, p < 0.01) than did other male chrome workers (observed 9, expected 13.70, SMR 66, 95% CI 30 to 125). Similar findings were shown for female workers (chrome bath workers: observed 15, expected 8.57, SMR 175, 95% CI 98 to 289, p = 0.06; other chrome workers: observed 1, expected 4.37, SMR 23, 95% CI 1 to 127). Poisson regression was used to investigate risks of lung cancer relative to four categories of cumulative duration of chrome bath work and four categories of cumulative duration of other chrome work (none, < 1 y, 1-4 y, > or = 5 y). After adjusting for sex, age, calendar period, year of starting chrome work, period from first chrome work, and employment status (still employed v left employment), there was a significant positive trend (p < 0.05) between duration of chrome bath work and risks of mortality for lung cancer. Relative to a risk of unity for those chrome workers without any period of chrome bath work, risks were 2.83 (95% CI 1.47 to 5.45), 1.61 (95% CI 0.75 to 3.44), and 4.25 (95% CI 1.83 to 9.87) for the second, third, and fourth exposure categories, respectively. Duration of other chrome work was not a useful predictor of risks of lung cancer. Similar findings for both variables were obtained when adjustment was made for sex and age only. Similar findings for both variables were obtained relative to risk of chrome nasal ulceration. CONCLUSIONS: The findings are consistent with the hypothesis that soluble hexavalent chromium compounds are potent human lung carcinogens.

Mortality study of nickel platers with special reference to cancers of the stomach and lung, 1945-93.

OBJECTIVES: To re-examine mortality patterns in a cohort of nickel platers with no history of chromium plating. METHODS: All 284 men first employed by the company in 1945-75 with a minimum employment of three months in the nickel plating department were identified. Workers who had worked in the chromium plating or nickel/chromium plating departments were excluded. Standardised mortality ratios (SMRs), P values, and 95% confidence intervals were calculated. Poisson regression was used to carry out statistical modelling of mortalities within the cohort (internal standard). Four variables were considered to have the potential to influence mortality within the cohort: attained age (age at follow up or age at death), year of starting nickel work, period of follow up (measured from the first period of work with nickel exposure), and duration of exposure to nickel. RESULTS: The only significant difference between observed and expected numbers, when investigated by site of cancer and by broad non-cancer groupings, was that for stomach cancer (observed eight, expected 2.49, SMR 322). CONCLUSIONS: The study provides only weak evidence that nickel plating is associated with an excess risk of stomach cancer. This cohort of nickel platers does not seem to have experienced any discernible risk of occupational lung cancer. Other studies of nickel platers rather than nickel/chromium platers would be useful.

A mortality study of nickel/chromium platers.

The mortality experienced by a cohort of 2689 nickel/chromium platers between 1946 and 1983 has been investigated. All members of the study cohort had some period of chrome exposed employment. Overall, compared with the general population of England and Wales, statistically significant differences relating to cancer were found for cancer of the stomach (E = 16.2, O = 25), primary cancer of the liver (E = 0.8, O = 4), cancer of the nose and nasal cavities (E = 0.3, O = 3), cancers of the lung and bronchus (E = 48.1, O = 72), and all cancers (E = 164.2, O = 213). Chrome bath workers are the more heavily exposed workers, and a striking difference in SMRs was found for lung cancer among men first employed as chrome bath workers (SMR = 199) and men first employed as other chrome workers (SMR = 101). The method of regression models in life tables (RMLT) was used to compare the durations of chrome exposed employment of those dying from causes of interest with those of all matching survivors in the same year of follow up, while controlling for sex, and for year and age of starting employment. Significant positive associations were found only for cancers of the lung and bronchus and duration of chrome bath work. In this study exposure to nickel was shown not to be an important confounding exposure.