Recent geographic patterns of lung cancer and mesothelioma mortality rates in 49 shipyard counties in the United States, 1970-94

BACKGROUND

Lung cancer mortality rates among white males in the United States were observed to be elevated during 1950-69 in counties with shipbuilding industries during World War II; risk was found to be associated with asbestos exposure. We evaluated the geographic patterns in more recent years, 1970-94, for whites and compared them with the 1950-69 patterns.

METHODS

We calculated age-adjusted rates and estimated rate ratios between comparison groups.

RESULTS

Rates generally were higher in shipyard counties than in all nonshipyard counties and in coastal nonshipyard counties for both sexes and time periods. Rates increased markedly from 1950-69 to 1970-94 in all groups, with the changes more pronounced in females than males. Pleural mesothelioma mortality rates were also significantly higher in shipyard counties than coastal nonshipyard counties in all regions among males but not among females.

CONCLUSIONS

The more pronounced changes in lung cancer mortality rates among females in shipyard counties may be attributed to the combined effects of low asbestos exposures and changes in smoking behavior. Am. J. Ind. Med. 37:512-521, 2000. Published 2000 Wiley-Liss, Inc.

Analysis of DNA adduct, S-[2-(N7-guanyl)ethyl]glutathione, by liquid chromatography/mass spectrometry and liquid chromatography/tandem mass spectrometry

Sensitive and specific isotope dilution liquid chromatography/mass spectrometry (LC/MS) and liquid chromatography/tandem mass spectrometry (LC/MS/MS) methods were developed for the detection and quantitative analysis of S-[2-(N7-guanyl)ethyl]glutathione as a DNA adduct formed upon exposure of animals to carcinogenic 1,2-dihaloethanes. Separation and analysis were performed using microbore HPLC coupled in-line to an electrospray ionization triple quadrupole mass spectrometer. S-[2-(N7-guanyl)[2H4]-ethyl] glutathione was synthesized and used as internal standard. These methods provide structural confirmation of the adduct as well as quantitative analysis with the accuracy and precision necessary to measure biologically relevant levels in small tissue sample sizes (< 1 g). The sample detection limits in in vivo tissue extracts were 100 pg and 5 pg on-column for LC/MS and LC/MS/MS methods, respectively. Selected-ion monitoring mode was used to monitor the product ions of the doubly charged molecular ion. The application of these methods was demonstrated by measuring the DNA adduct levels in rat and fish samples after exposure to 1,2-dihaloethanes. The method has application in studies of DNA adduct formation as a biological marker of exposure to carcinogens and for environmental monitoring of 1,2-dihaloethanes.

The estimated long-term impact of tsetse control on the size of the population of cattle in the Didessa Valley, western Ethiopia

The long-term impact of tsetse control on cattle population size in the Didessa Valley, western Ethiopia, was analysed using an age-structured population model. A prior analytical assessment revealed that the risk of cattle dying in the tsetse-unprotected villages ranged from 4 to 9 times higher than in the tsetse-protected village. Model results show that during a period of 10 years the cattle population in the tsetse-protected village of Meti is likely to increase from 167 to 583 animals, while that in the adjacent tsetse-unprotected village of Gale remains almost constant. Model simulations also predict that improving the survival rate of calves in the tsetse-unprotected villages of Taikiltu and Temoloko (which presently have calf mortality rates of up to 35% would bring a substantial increase in their cattle population.