Biomedical subjects
T Schnorr
Publications and source records attributed to T Schnorr.
A dose-response analysis and quantitative assessment of lung cancer risk and occupational cadmium exposure.
We performed a quantitative assessment of the risk of lung cancer from exposure to cadmium based on a retrospective cohort mortality study of cadmium-exposed workers. The study population consisted of white male workers who were employed for at least 6 months at a cadmium smelter between January 1, 1940, and December 31, 1969, and who were first employed at the facility on or after January 1, 1926. The study findings were analyzed using a modified life-table analysis to estimate standardized mortality ratios (SMRs), and various functional forms (i.e., exponential, power, additive relative rate, and linear) of Poisson and Cox proportional hazards models to examine the dose-response relationship. Estimates of working lifetime risk (45 years) were developed using an approach that corrects for competing causes of death. An excess in mortality from lung cancer was observed for the entire cohort (SMR = 149, 95% confidence interval (CI) = 95, 222). Mortality from lung cancer was greatest among non-Hispanic workers (SMR = 211, 95% CI = 131, 323), among workers in the highest cadmium exposure group (SMR = 272, 95% CI = 123, 513), and among workers with 20 or more years since the first exposure (SMR = 161, 95% CI = 100, 248). A statistically significant dose-response relationship was evident in nearly all of the regression models evaluated. Based on our analyses, the lifetime excess lung cancer risk at the current Occupational Safety and Health Administration standard for cadmium fumes of 100 micrograms/m3 is approximately 50 to 111 lung cancer deaths per 1000 workers exposed to cadmium for 45 years.
A quantitative assessment of lung cancer risk and occupational cadmium exposure.
We have performed a quantitative assessment of the risk of lung cancer from exposure to cadmium based on a retrospective cohort mortality study of cadmium-exposed workers. The findings were analysed using a life-table analysis to estimate standardized mortality ratios (SMRs), and various functional forms of Poisson and Cox proportionate hazards models to examine dose-response relationships. An excess mortality from lung cancer was observed for the entire cohort (SMR = 149,95% CI = 95-222). Lung cancer mortality was significantly elevated among non-hispanic workers, among those in the highest cadmium-exposure group, and among workers with 20 or more years since first exposure. A statistically significant dose-response relationship was evident in nearly all of the regression analyses. Based on our analyses, the lifetime excess lung cancer risk at the current OSHA standard for cadmium fumes of 100 micrograms/m3 is approximately 50-111 lung cancer deaths per 1000 workers exposed to cadmium for 45 years.
Incidence of laryngeal cancer and exposure to acid mists.
To determine the relation between exposure to acid mist and laryngeal cancer, the smoking habits, drinking habits, and incidence of laryngeal cancer of 879 male steelworkers exposed to acid mists during pickling operations was ascertained. Sulphuric acid mist was the primary exposure for most men in this cohort. These men had all worked in a pickling operation for a minimum of six months before 1965, with an average duration of exposure of 9.5 years. Exposures to sulphuric acid in the 1970s averaged about 0.2 mg/m3, and earlier exposures were probably similar. Interviews were conducted with all cohort members or their next of kin in 1986 and medical records of decedents were reviewed. Nine workers were identified who had been diagnosed as having laryngeal cancer, using a conservative case definition that required medical record confirmation for any case among decedents and confirmation by a physician for any case among live individuals. Using data from national surveys of cancer incidence as referent rates, 3.44 laryngeal cancers would have been expected. Excess smoking by the exposed cohort compared with the United States population resulted in an upward adjustment of the expected number of cases of laryngeal cancer to 3.92. The standardised incidence rate ratio for laryngeal cancer was 2.30 (9/3.92), with a one sided p value of 0.01 (assuming a Poisson distribution). The finding of excess laryngeal cancer in this cohort is consistent with four other studies published since 1981.
Availability and accuracy of cancer and smoking data obtained from next of kin for decedents in a retrospective cohort study.
We report on the availability and accuracy of next-of-kin data on 372 decedents gathered in the conduct of a retrospective cancer incidence study. Two mailed questionnaires were followed by phone calls for nonrespondents. The overall response rate for the next of kin of decedents was 59%, markedly less than the 79% response rate for living cohort members. Validity of data provided by next of kin regarding cancer incidence and smoking habits of the decedents was assessed via a comparison with medical records, which were considered accurate for the purposes of this comparison. For the 117 men for whom we had both types of records, next of kin were generally able to report accurately both whether the decedent ever had cancer (91% agreement) and the cancer type (84% agreement). Next-of-kin data generally agreed with medical record data for number of years smoked or for number of years since quitting, whereas next of kin underreported the amount smoked by decedents. The difficulty in contacting next of kin and their frequent inability to provide detailed and accurate information on smoking may make it difficult to adjust for confounding by smoking in nested case-control studies.