Magnetic field exposure and long-term survival among children with leukaemia.

We examined the association between magnetic field (MF) exposure and survival among children with acute lymphoblastic leukaemia (ALL) treated at 51 Pediatric Oncology Group centres between 1996 and 2001. Of 1672 potentially eligible children under treatment, 482 (29%) participated and personal 24-h MF measurements were obtained from 412 participants. A total of 386 children with ALL and 361 with B-precursor ALL were included in the analysis of event-free survival (time from diagnosis to first treatment failure, relapse, secondary malignancy, or death) and overall survival. After adjustment for risk group and socioeconomic status, the event-free survival hazard ratio (HR) for children with measurements >/=0.3 muT was 1.9 (95% confidence interval (CI) 0.8, 4.9), compared to <0.1 muT. For survival, elevated HRs were found for children exposed to >/=0.3 muT (multivariate HR=4.5, 95% CI 1.5-13.8) but based on only four deaths among 19 children. While risk was increased among children with exposures above 0.3 muT, the small numbers limited inferences for this finding.

Alternative magnetic field exposure metrics: relationship to TWA, appliance use, and demographic characteristics of children in a leukemia survival study.

The ongoing Childhood Leukemia Survival Study is examining the possible association between magnetic field exposure and survival of children with newly diagnosed acute lymphocytic leukemia (ALL). We report the results of the first year 24 h personal magnetic field monitoring for 356 US and Canadian children by time weighted average TWA and alternative exposure metrics. The mean TWA of 0.12 microT was similar to earlier personal exposure studies involving children. A high correlation was found between 24 h TWA and alternative metrics: 12 h day TWA, 12 night TWA, geometric mean, 95th percentile value, percentage time over 0.2 and 0.3 microT, and an estimate of field stability (Constant Field Metric). Two measures of field intermittency, rate of change metric (RCM) and standardized rate of change metric (RCMS), were not highly correlated with TWA. The strongest predictor of TWA was location of residence, with highest TWAs associated with urban areas. Residence in an apartment, lower paternal educational level, and residential mobility were also associated with higher TWAs. There were no significant differences in the appliance use patterns of children with higher TWA values. Children with the highest field intermittency (high RCM) were more likely to sit within 3 feet of a video game attached to the TV. Our results suggest that 24 h TWA is a representative metric for certain patterns of exposure, but is not highly correlated with two metrics that estimate field intermittency.

Bereavement practices among California hospices: results of a statewide survey.

During 1999-2000, the California Hospice and Palliative Care Association (CHAPCA) surveyed its 160 member hospices regarding bereavement support services. Over 80% of hospices participated, providing information about program content, staff training, and costs incurred by participants. Results revealed that a greater percentage of larger hospices and non-profit hospices offer support groups and workshops than do smaller hospices and for-profit hospices. Volunteers account for almost one quarter of bereavement staff. The professional background of paid staff is varied, with social workers and clergy being most common overall but nurses more common in small hospices. Almost 90% of hospices provide all bereavement support at no charge to the bereaved. Services most likely to be associated with a fee include special support groups, children's programs, and professional counseling to individuals and families.

Swanson silicone finger joint implants: a review of the literature regarding long-term complications.

A review of the English-language literature pertaining to complications associated with Swanson Silastic (Dow Corning, Midland, MI) finger implants was performed. The review focused on seven broad categories of complications: synovitis, lymphadenopathy, bone change, implant fracture, implant loosening, infection, and implant removal. Outcome data on 15,556 small joint implants were identified in 70 pertinent articles. The prevalence rates of complications associated with finger implants were all very low. Implant fracture and bone changes occurred in 2% and 4% (respectively) of finger implants. Each of the other complications developed in 1% or less of implants, including particulate synovitis (0.06% of implants). Particle-wear lymphadenopathy was reported in 0.08% of implants. The literature review identified no reports of immunologic reactions, connective tissue disease, or other systemic effects associated with the use of Swanson finger implants.

Epidemiological factors of cancer in Louisiana.

Certain Louisiana cancer rates are higher than the national averages. This review evaluates the existing epidemiologic literature pertaining to risk factors for cancer in Louisiana. Population-based case-control studies have identified smoking as the most important contributor to lung cancer in Louisiana. Nutritional factors have been found to impart a modest increase in lung, pancreas, and stomach cancer risk. Occupational epidemiologic studies have revealed exposure to asbestos in the cement, shipbuilding, and related industries as a significant risk factor for mesothelioma and lung cancer. Sugarcane farming has been found to increase the risk of lung cancer among sugarcane farmers who smoke, and the risk of mesothelioma among sugarcane farmers in general. Occupations with exposure to microwave and radio frequency electromagnetic radiation have been associated with an increased risk of brain cancer. An increased risk of laryngeal cancer has been observed among workers exposed to sulfuric acid at a Baton Rouge isopropyl alcohol plant. Except for the laryngeal cancer finding, data from occupational cohort studies of refinery/chemical workers revealed no significant excess in cancer of all sites, cancer of the lung, or any other cancer. Relevant epidemiologic data also revealed no increased cancer risk associated with potential exposures to industrial emissions among residents in communities adjacent to petrochemical facilities.

An ecologic study of skin cancer and environmental arsenic exposure.

We conducted an epidemiologic study of skin cancer incidence rates for four counties in Montana. The two counties considered to be exposed to arsenic were Deer Lodge, containing the former Anaconda copper smelter, and Silver Bow, containing an open pit copper mine. Residents in these counties had potential exposure to arsenic and other heavy metals. Gallatin and Park counties served as controls. All histologically proven skin cancer cases during the period January 1980 through June 1986 were collected from pathology services and dermatologists in these four counties. In addition, all skin cancer cases from four dermatologists practicing in urban referral areas outside the counties were reviewed. Results were analyzed by individual as well as by two different definitions of anatomically distinct lesions: the National Cancer Institute (NCI) definition and the study definition. There were 1616 individuals with skin cancer in the four counties during the period under consideration, yielding 2252 (NCI definition) and 2451 (study definition) cases. The clinical features of the skin cancers in the exposed counties were not similar to those described for arsenic-related skin cancer. The age-adjusted annual skin cancer rates were higher for the two control counties as compared to either the county with the former smelter, Deer Lodge, or the county with the mine, Silver Bow. Our results cannot be explained by differences in ascertainment, latitude, or altitude. They can be partially explained by differences in both outdoor employment and medical practice. The overall skin cancer incidence rates for the exposed counties were well within the range of skin cancer rates observed for other locations in the United States.

A case-control study of lung cancer in a cohort of workers potentially exposed to slag wool fibres.

A cohort of 4841 men were identified as having worked for more than a year at nine slag wool plants. Some of these men were potentially exposed to man made vitreous fibres (MMVF). The vital status of the entire cohort was ascertained to the end of 1989. Of the 504 deaths that occurred between 1970 and 1989, 61 were attributed to lung cancer (cases). Individually matched controls were randomly selected from the remaining deaths. Attempts were made to locate and interview the surviving families of the cases and controls. The families of three lung cancer cases could not be located and no matched controls were found for another three cases. Included in the final analysis were 55 cases and 98 controls. Estimates of individual exposure to MMVF were based on employment records and industrial hygiene surveys. Data on smoking and histories of employment outside the MMVF industry were obtained from telephone interviews and employment records. Relative risks were calculated for cigarette smoking and exposure to MMVF. No increased risk of lung cancer was found associated with exposure to MMVF, and analysis by cumulative fibre exposure did not indicate any trend. As expected, cigarette smoking was found to be responsible for the observed increase in mortality from lung cancer in this group of MMVF workers, and the risk increased with increasing pack-years of cigarette smoking.

An industry-wide epidemiologic study of vinyl chloride workers, 1942-1982.

The cohort consisted of 10,173 men who had worked for at least one year in jobs involving exposure to vinyl chloride prior to 1 January 1973. These men were employed at 37 plants in the U.S., belonging to 17 companies. Observation of the mortality experience of the cohort was updated from 31 December 1972 to 31 December 1982 (the study now covering 1942-1982). A total of 1,536 cohort members were identified as having died. The observed mortality, by cause, was compared with the expected based on U.S. mortality rates, standardized for age, race, and calendar time. Analyses by length of exposure, latency, age at first exposure, calendar year of first exposure, and type of products were performed. The study confirmed that the vinyl chloride workers experience a significant mortality excesses in angiosarcoma (15 deaths), cancer of the liver and biliary tract (SMR = 641), and cancer of the brain and other central nervous system (SMR = 180). In addition, the study also found a significant mortality excess in emphysema/chronic obstructive pulmonary disease (COPD) (SMR = 179). On the other hand, the study did not find any excess in either respiratory cancer or lymphatic and hematopoietic cancer. This study also found an increase in biliary tract cancers, independent from liver cancer.

Asbestos and gastrointestinal cancer. A review of the literature.

Exposure to asbestos is among several factors cited as possible causes of esophageal, gastric and colorectal cancer. More than 45 published studies have presented mortality data on asbestos-exposed workers. For each cohort, we listed the observed and expected rates of deaths from types of gastrointestinal cancer based on the latest published follow-up. Summary standardized mortality ratios (SMRs) were then derived. Finally, we calculated summary SMRs for total gastrointestinal tract cancer for three occupational groups: asbestos factory workers, insulators/shipyard workers and asbestos miners. Statistically significant elevations in summary SMRs were found for esophageal, stomach and total gastrointestinal tract cancer in all asbestos-exposed workers. Esophageal cancer summary SMRs remained significantly elevated when data were reanalyzed to include only those cohorts with death certificate diagnoses for cause of observed deaths. However, summary SMRs were not statistically significant for stomach and total gastrointestinal tract cancer after reanalysis. Summary SMRs by occupational group showed a significant elevation for total gastrointestinal cancer in insulators/shipyard workers. The elevation was not significant after reanalysis. Based on the results after reanalysis, the elevations in summary SMRs for stomach and total gastrointestinal tract cancer are of a magnitude that could result from diagnostic and investigator error. We conclude that more studies are required before stomach and colorectal cancers are documented as asbestos-related diseases.

Fetal loss and work in a waste water treatment plant.

We investigated pregnancy outcomes in 101 wives of workers employed in a waste water treatment plant (WWTP), and verified fetal losses by hospital records. Paternal work histories were compiled and each of the 210 pregnancies was assigned a paternal exposure category. The relative risk of fetal loss was increased when paternal exposure to the WWTP occurred around the time of conception.

Mutagenicity, carcinogenicity and reproductive effects of dibromochloropropane (DBCP).

Dibromochloropropane (DBCP), a brominated organochlorine nematocide, has been used since the mid-1950s. Its primary value was its effectiveness on perennial crops without damaging the plants. DBCP also had less acute toxicity than earlier soil fumigants such as ethylene dibromide. DBCP became widely used on citrus, grapes, peaches, pineapple, soybeans and tomatoes. In Central America and Israel, banana trees were treated with DBCP. By 1975, 25 million pounds were being produced in the U.S. per year. The majority of U.S. production was applied in the Pacific Coast states, particularly California's San Joaquin Valley, and the Southern Atlantic Coast states. Animal studies in the early 1960s revealed hepatic and renal effects and testicular atrophy in DBCP-treated rates. Testicular atrophy was noted at the lowest exposure level tested (5 ppm). In 1973, DBCP was found to cause gastric carcinoma in mice and rats, and mammary adenocarcinoma in rats. A later study linked DBCP to nasal cavity tumors in rats. DBCP is an in vitro mutagen after activation with microsomal enzymes. A dominant lethal effect has been observed in rats. DBCP also induces increases in sister-chromatid exchanges and chromosomal aberrations. Mean fetal weight and maternal weight gain is decreased in pregnant rats exposed to DBCP. In mid-1977, employees in a California pesticide formulation plant were discovered to be infertile. Further investigations documented azoospermia and oligospermia among many of the workers handling DBCP. These findings were duplicated in other DBCP production plants. In the United States, the Occupational Safety and Health Administration (OSHA) and the Environmental Protection Agency (EPA) rapidly restricted the use of DBCP. The application of DBCP to all but pineapples in Hawaii was banned by the EPA in 1979. In 1982, the EPA exempted the peach crop in the Southern Atlantic coast states from the ban on DBCP use. Prior to the 1977 events, no such agent in workplace concentrations had been shown to produce infertility and sterility in otherwise healthy men. Subsequently, the interest in DBCP had led to many other studies, and has contributed to a heightened awareness about workplace hazards to both the male and female reproductive systems. This article will review the current state of knowledge of the in vitro, animal, and human toxicology of DBCP.

A model poison control system.

Responding to the need for a poison information, education, data collection and research resource in California's Bay Area and North Coast counties, the San Francisco Bay Area Regional Poison Control Center has become an integral part of the region's emergency medical services. In the first 33 months after it opened, more than 54,000 calls for assistance were received, nearly a third from medical professionals. Through the cooperation and collaboration of public, private and university resources and interests, a cost-effective, comprehensive and accessible system has evolved for public and professional use. Through our experience a system has developed that can serve as a model for poison information services throughout the western states. Emerging public concern for toxicology issues will continue to refine this model.