Optimizing BeLPT criteria for beryllium sensitization.

BACKGROUND: The beryllium lymphocyte proliferation test (BeLPT) is used to identify persons sensitized to beryllium. ATSDR convened an expert panel of physicians and scientists in April 2006 to discuss this test and to consider what BeLPT test results actually establish beryllium sensitization. The three criteria proposed by panel members were (1)one abnormal result, (2)one abnormal and one borderline result, and (3)two abnormal results. METHODS: Complete algorithms were developed for each of the three proposed criteria. Using single-test outcome probabilities developed by Stange et al. [2004. Am J Ind Med 46:453-462], we calculated and compared the sensitivity, specificity, and positive predictive values (PPVs) for each set of criteria. RESULTS: The overall sensitivity and specificity of the three criteria were similar. When the criteria required confirmation of an abnormal result the PPV was higher--whether the requirement was satisfied by a borderline result, or only by another abnormal result. Confirmation also reduced the likelihood of false positives. The differences between the three criteria decreased as the prevalence of sensitization increased. CONCLUSIONS: A single unconfirmed abnormal is usually insufficient to establish sensitization for an apparently healthy person. When the prevalence of beryllium sensitization in a group is high, however, even a single abnormal BeLPT can be a strong predictor.

Urinary mercury concentrations associated with dental restorations in adult women aged 16-49 years: United States, 1999-2000.

BACKGROUND: Mercury amalgam dental restorations have been used by dentists since the mid 19th century and issues on safety continue to be periodically debated within the scientific and public health communities. Previous studies have reported a positive association between urine mercury levels and the number of dental amalgams, but this relation has never been described in a nationally representative sample in the United States. AIMS AND METHODS: Using household interview, dietary interview, dental examination, and laboratory data from the 1999-2000 National Health and Nutrition Examination Survey (NHANES), the association between mercury concentrations and dental restorations was examined in US women of reproductive age. RESULTS: In women of childbearing age, approximately 13% of all posterior dental surfaces were restored with amalgams and the average urinary mercury level in women was low (1.34 microg/l). It is estimated that an increase of 1.8 microg/l in the log transformed values for mercury in urine would occur for each 10 dental surfaces restored with amalgam. CONCLUSIONS: Although the findings do not address the important issues of adverse health effects at low thresholds of mercury exposure, they do provide important reference data that should contribute significantly to the ongoing scientific and public health policy debate on the use of dental amalgams in the USA.

Copper in drinking water, Nebraska, 1994.

In 1993, the levels of copper (Cu) in much of Nebraska's drinking water exceeded the U.S. Environmental Protection Agency's (EPA) action level of 1.3 mg/L. To determine the association of copper with gastrointestinal (GI) illness in August 1994 the authors interviewed persons living in households with 1993 Cu levels > 3 mg/L (51 households), 2-3 mg/L (54 households), and < 1.3 mg/L (43 households). Cases were defined as persons who had experienced the rapid onset of vomiting or nausea with abdominal pain during the preceding two weeks. To validate their exposure index, the authors immediately resampled drinking water in the households of 25 cases and 27 controls matched for age. Reassessment in December 1994 of the exposure and case status of the original cohort showed no association between copper in drinking water in 1993 and case status in 1994. The risk of GI illness seemed no greater with Cu > 3 mg/L (RR = 1.03; 95% CI = 0.43, 2.49) or 2-3 mg/L (RR = 0.50; 95% CI = 0.18, 1.41) than with Cu < 1.3 mg/L. The 1993 Cu concentrations could not be reproduced in August 1994; resampling in December 1994 again showed no association between GI illness and Cu exposure (RR > 1.3-2.9 mg/L, < or = 1.3 mg/L = 0.25, 95% CI = 0.10, 0.64, and RR > or = 3.0 mg/L, < or = 1.3 mg/L = 0.36, 95% CI = 0.09, 1.49).

Cardiovascular mortality--the hidden peril of heat waves.

OBJECTIVE: Define the mortality associated with extremely hot weather during the 04 July through 14 July, 1993 heat wave that struck the northeastern United States. METHODS: DESIGN--A rapid field assessment was used to compare mortality occurring during the heat wave to mortality occurring during a period in which there was no heat wave using copies of death certificates. The findings of the rapid field assessment were validated, and it was determined whether increases in mortality occurred in other metropolitan east-coast counties also affected by the heat wave, by reviewing computerized mortality files. SETTING--Information was collected on all deaths occurring in Baltimore City, Maryland; Baltimore County, Maryland; Essex County, New Jersey; Newcastle County, Delaware; and Philadelphia County, Pennsylvania; during these specified study periods: 08-18 June (comparison period) and 06-16 July (heat wave study period), 1993. MAIN OUTCOME MEASURES--Ratios for total mortality, cause-specific mortality, and variables such as age, sex, race, residence, and day and place of death, that were available from death certificates were calculated. RESULTS: From the rapid field assessment, the following were observed: a 26% increase in total mortality and a 98% increase in cardiovascular mortality associated with the heat wave in Philadelphia. Data from the computerized mortality files showed an increase in total mortality in four of five counties examined and an increase in cardiovascular mortality in all five counties. The risk for death for those dying from cardiovascular disease increased significantly for people older than 64 years, for both sexes, and all races. CONCLUSION: As initially indicated by the Philadelphia Medical Examiner, there was excess mortality associated with a heat wave in Philadelphia. All other nearby counties examined also experienced excess mortality associated with the heat wave, although this excess was not recognized by the local health officials. The true impact of a heat wave that causes excess preventable mortality must be appropriately and rapidly ascertained. Using a national standard to certify a death as heat-related will provide the needed information rapidly so that public health resources can be more effectively allocated and mobilized to prevent further heat-related illnesses and death.

Changing sex ratio in the United States, 1969-1995.

OBJECTIVE: To determine if the sex ratio of live births in the United States has changed during the 27 years from 1969 through 1995. DESIGN: Regression analysis of secular trends in sex ratios. SETTING: Population-based data. PATIENT(S): Liveborn infants in the United States 1969-1995. MAIN OUTCOME MEASURE(S): Sex of liveborn infant. RESULT(S): The sex ratio (number of male births divided by number of female births) declined significantly among whites during the 27 years under study. Among black newborns, the sex ratio significantly increased during the same time period. CONCLUSION(S): These secular trends could not be explained by changing maternal or paternal age, or by changing proportions of specific birth orders. Possible explanations for the observed changes in sex ratio include random fluctuations in sex ratio over time, changes in demographic characteristics of the population (other than the characteristics controlled for in this analysis), and changes in frequency or timing of intercourse. Environmental exposures are unlikely to account for the observed trends.

The U.S. federal framework for research on endocrine disruptors and an analysis of research programs supported during fiscal year 1996.

The potential health and ecological effects of endocrine disrupting chemicals has become a high visibility environmental issue. The 1990s have witnessed a growing concern, both on the part of the scientific community and the public, that environmental chemicals may be causing widespread effects in humans and in a variety of fish and wildlife species. This growing concern led the Committee on the Environment and Natural Resources (CENR) of the National Science and Technology Council to identify the endocrine disruptor issue as a major research initiative in early 1995 and subsequently establish an ad hoc Working Group on Endocrine Disruptors. The objectives of the working group are to 1) develop a planning framework for federal research related to human and ecological health effects of endocrine disrupting chemicals; 2) conduct an inventory of ongoing federal research programs; and 3) identify research gaps and develop a coordinated interagency plan to address priority research needs. This communication summarizes the activities of the federal government in defining a common framework for planning an endocrine disruptor research program and in assessing the status of the current effort. After developing the research framework and compiling an inventory of active research projects supported by the federal government in fiscal year 1996, the CENR working group evaluated the current federal effort by comparing the ongoing activities with the research needs identified in the framework. The analysis showed that the federal government supports considerable research on human health effects, ecological effects, and exposure assessment, with a predominance of activity occurring under human health effects. The analysis also indicates that studies on reproductive development and carcinogenesis are more prevalent than studies on neurotoxicity and immunotoxicity, that mammals (mostly laboratory animals) are the main species under study, and that chlorinated dibenzodioxins and polychlorinated biphenyls are the most commonly studied chemical classes. Comparison of the inventory with the research needs should allow identification of underrepresented research areas in need of attention.

Public health surveillance after a volcanic eruption: lessons from Cerro Negro, Nicaragua, 1992.

The eruption of the Cerro Negro volcano near León, Nicaragua, on 9 April 1992 distributed an estimated 1.7 million tons of ash over a 200 square kilometer area. An assessment was conducted to evaluate the health effects on approximately 300,000 residents, using routine data obtained by the national epidemiologic surveillance system. It was found that rates of visits to health care facilities for acute diarrheal and respiratory illnesses increased in two study communities, one within and one near the disaster zone. Specifically, visits for acute diarrhea were nearly 6 times more numerous than before the eruption in both communities, while visits for acute respiratory diseases were 3.6 times more frequent in Malpaisillo (the community near the disaster zone) and 6.0 times more frequent in Telica (the community within it). Most of the visits were for infants and children less than 5 years old. Increased diarrheal disease morbidity, which commonly occurs after volcanic eruptions, demands detailed investigation of the type and quality of water supplies following heavy ashfall. Ash-related respiratory problems should be further examined to determine the spectrum of such diseases and the timing of illness onsets among infants and other special population subgroups. Data collected on health conditions before and after an eruption by passive surveillance can be used to detect eruption-related morbidity. Systems already in place, such as Nicaragua's national epidemiologic surveillance system, can be modified or extended so as to increase their sensitivity to new cases and hence their ability to provide appropriate notification to medical relief agencies.

Research needs for the risk assessment of health and environmental effects of endocrine disruptors: a report of the U.S. EPA-sponsored workshop.

The hypothesis has been put forward that humans and wildlife species adverse suffered adverse health effects after exposure to endocrine-disrupting chemicals. Reported adverse effects include declines in populations, increases in cancers, and reduced reproductive function. The U.S. Environmental Protection Agency sponsored a workshop in April 1995 to bring together interested parties in an effort to identify research gaps related to this hypothesis and to establish priorities for future research activities. Approximately 90 invited participants were organized into work groups developed around the principal reported health effects-carcinogenesis, reproductive toxicity, neurotoxicity, and immunotoxicity-as well as along the risk assessment paradigm-hazard identification, dose-response assessment, exposure assessment, and risk characterization. Attention focused on both ecological and human health effects. In general, group felt that the hypothesis warranted a concerted research effort to evaluate its validity and that research should focus primarily on effects on development of reproductive capability, on improved exposure assessment, and on the effects of mixtures. This report summarizes the discussions of the work groups and details the recommendations for additional research.

Environmental Exposure to Organic Mercury among the Makuxi in the Amazon Basin.

Gold mining in the savannah region of northern Brazil (Roraima) has increased dramatically since 1989. Elemental mercury is used to extract gold from sediment. Mercury released into the Amazon aquatic ecosystem may convert into the organic form and bioconcentrate in the food chain, posing a hazard for fish-eating peoples such as some of the Makuxi. This survey compared blood organic mercury levels among Makuxi villagers along mined (Rio Cotingo) and unmined (Rio Surumu) rivers. Seventy-five blood samples were obtained from villagers who did not participate in gold mining or processing procedures in three Makuxi villages: Maravilha (heavily exposed), Limão (limitedly exposed), and Matarucca (minimally exposed). Blood was analyzed for total and inorganic mercury content by cold vapor spectrophotometry. Mean blood organic mercury levels among the villagers of Maravilha, Limão, and Matarucca were 31.3 mg/L, 9.3 mg/L, and 2.0 mg/L, respectively (p = 0.001). The authors conclude the gold mining process is contaminating the environment of Roraima and may pose a health hazard to its fish-eating populations, such as the Makuxi people.

An Economic Analysis of Water and Sanitation Infrastructure Improvements in the Colonias of El Paso County, Texas.

The authors conducted a cost-benefit analysis of a project to improve water supply and sanitation infrastructure in a rural community (colonia) along the United States-Mexico border. The present value of total costs in the scenario without improvements was $42,937,507, compared with net costs with improvements of $34,600,800. It is estimated that improved access to safe drinking water and solid waste sanitation prevented 155 cases of hepatitis A and 5,165 cases of gastrointestinal illness over 26 years and saved $846,541 in associated health care costs, approximately 10% of the total estimated savings. The majority of benefits was in the form of time savings and increased land values. The authors did not consider the value of improving environmental conditions for future generations and preventing communicable disease epidemics associated with poor sanitation. Accurate value estimates for these benefits might strengthen the argument for undertaking similar infrastructure-improvement projects in the colonias and in other underdeveloped rural areas of the United States. cost-benefit analysis; water supply and sanitation; health care costs; disease-prevention effectiveness Hanley & Belfus, Inc. Int J Occup Environ Health 1077-3525 2 3 1996 July/September Decreases in Subpopulations of T Lymphocytes and Natural Killer Cells in the Blood of Retired Chromate Workers 222 225 EN Takeshi Tanigawa Shunichi Araki Department of Public Health, Faculty of Medicine, University of Tokyo 7-3-1 Hongo, Bunkyo-ku, Tokyo 113, Japan. Akinori Nakata Takaharu Araki Susumu Sakurai To examine the effects of past exposure to chromates on lymphocyte subpopulations in man, the authors measured subpopulations of T lymphocytes and natural killer (NK) cells by flow cytometry together with B lymphocytes in blood samples from 27 male workers and 22 healthy controls. All subjects were nonsmokers. The numbers of CD4+CD45RA+ (suppressor-inducer), CD8+ (suppressor/cytotoxic) and total T lymphocytes, CD16+CD57+ NK cells, and total lymphocytes in the blood of chromate workers were significantly smaller than those in the blood of healthy controls (analysis of covariance with age as a covariate). It is suggested that suppressor-inducer and suppressor/cytotoxic T lymphocytes and NK cells with intermediate NK cell activity are most susceptible to the effects of past exposure to chromates as compared with other lymphocyte subpopulations such as B and CD4+CD29+ T lymphocytes.

The World Trade Center bombing: injury prevention strategies for high-rise building fires.

The WTC disaster provided an opportunity to look for ways to prevent morbidity among occupants of high-rise buildings during fires. This paper first describes the overall morbidity resulting from the explosion and fire, and second, presents the results of a case-control study carried out to identify risk factors for smoke-related morbidity. The main ones include: increased age, presence of a pre-existing cardio-pulmonary condition, entrapment in a lift and prolonged evacuation time. Study results point to the importance of the following safety systems during high-rise building fires: smoke-control systems with separate emergency power sources; lift-cars, lift-car position-monitoring systems, and lift-car communication systems with separate emergency power sources; two-way emergency communication systems on all floors and in stairwells; stairwells with emergency lighting and designed for the rapid egress of crowds; evacuation systems/equipment to assist in the evacuation of vulnerable people (elderly, infirm). Also important are evacuation plans that include regularly scheduled safety training and evacuation drills.

The natural history of eosinophilia-myalgia syndrome in a tryptophan-exposed cohort in South Carolina.

BACKGROUND: In a previous study, we did follow-up on 418 patients who were exposed to tryptophan in 1989, of whom 47 (11%) had definite and 63 (9%) possible eosinophilia-myalgia syndrome (EMS). METHODS: We assessed mortality and clinical spectrum of illness since 1989 for 242 (58%) of the 418 tryptophan-exposed patients from the original study. To assess outcomes, we used hospital and death records, interviewer-administered questionnaires, physical examinations, and laboratory tests. RESULTS: During the follow-up interval, mortality from all causes was 19% in those with definite EMS, 7% in possible EMS, and 3% in those who were not ill. The age- and sex-adjusted mortality in those with definite EMS was more than 3 times that of the general population or of tryptophan users in the practice who were not ill. Six deaths (66%) among the definite EMS case patients occurred during the 18 months immediately after symptom onset. Compared with the tryptophan users who were not ill, survivors with definite EMS continued to report excess morbidity for 6 major EMS symptoms (myalgia, arthralgia, weakness, rash, alopecia, and sclerodermiform skin changes), but they also reported that the symptom number and severity diminished with time. None of the tryptophan users who were not ill in 1989 developed a symptom complex suggesting new EMS during the follow-up interval. CONCLUSIONS: This study assessing a tryptophan-exposed population found those persons who developed EMS during the 1989 epidemic were at increased risk for death, particularly early after disease onset. Survivors reported improvement or resolution of major symptoms, suggesting that the severity of EMS diminishes with time. We found no evidence of delayed onset of EMS in tryptophan users who were not ill in 1989, regardless of the brand used.

Assessment of a severe-weather warning system and disaster preparedness, Calhoun County, Alabama, 1994.

Tornado preparedness warning system effectiveness, and shelter-seeking behavior were examined in two Alabama areas after tornado warnings. In the area without sirens, only 28.9% of 194 respondents heard a tornado warning of these, 73.2% first received the warning from radios or television. In the area with sirens, 88.1% of 193 respondents heard a warning, and 61.8% first received the warning from a siren. Knowledge of warnings, access to shelter, and education were key predictors for seeking shelter. Our findings indicate that installing sirens, providing access to shelter, and teaching appropriate responses to warnings are important elements of an effective disaster prevention system.

Subclinical health effects in a population exposed to excess vitamin D in milk.

To evaluate subclinical health effects of excess vitamin D, a cross-sectional study was conducted of persons consuming milk from a dairy that had overfortified milk for at least 4 years. Milk consumption, sunlight exposure, medical symptoms, serum 25-hydroxyvitamin D (25[OH]D), serum and urinary calcium, and indicators of renal function were measured. Increased milk consumption was associated with increased serum 25(OH)D and urinary calcium. However, the prevalences of elevated serum 25(OH)D and calcium were no greater than expected, and data indicated normal renal function. It was concluded that most persons exposed to excess vitamin D exhibited no measurable adverse subclinical effects.

Breast cancer among women exposed to polybrominated biphenyls.

We conducted a nested case-control study with 1,925 women enrolled in a polybrominated biphenyl (PBB) registry to examine the association between breast cancer and serum PBBs. Twenty women who developed breast cancer were matched to 290 control subjects on sex, race, and age. Women with serum PBB levels of 2.0-3.0 parts per billion (ppb) [odds ratio (OR) = 3.5; 95% confidence interval (CI) = 0.9-13] or 4.0 ppb or greater (OR = 3.1; 95% CI = 0.8-12) had a higher estimated risk for breast cancer than women with less than 2.0 ppb. The odds ratios were unchanged when available breast cancer risk factors were included in the analysis.

An outbreak of hypervitaminosis D associated with the overfortification of milk from a home-delivery dairy.

OBJECTIVES: The purpose of the study was to identify cases of hypervitaminosis D caused by the inadvertent overfortification of milk from a home-delivery dairy and to identify risk factors for this illness. METHODS: Hospital discharge, laboratory, and state health department data were used to define, identify, and describe cases of hypervitaminosis D diagnosed in the exposed communities between January 1, 1985, and June 30, 1991. To identify disease risk factors, community-based sex- and age-matched controls were used in a case-control study. RESULTS: Of the 56 case patients identified, at least 41 were hospitalized; 2 died. The study included 33 case patients and 93 control subjects. Nineteen of the 33 case patients had been customers of the implicated dairy. Risk of illness rose with increasing consumption of the dairy's milk and was also associated with vitamin D supplement use, sunburn susceptibility, and cancer history. Accounting for these factors did not alter the association between drinking the dairy's milk and developing hypervitaminosis D. CONCLUSIONS: Overfortification of milk with vitamin D can lead to hypervitaminosis D, manifested by severe illness and death. The episode highlights the need for monitoring the fortification process and enforcing the upper limit for vitamin D addition to milk.

Half-life of polybrominated biphenyl in human sera.

Polybrominated biphenyl (PBB), a flame-retardant material, was introduced into the food chain in Michigan in 1973 due to a manufacturing and distribution mistake. Following public concern about the long-term health effects of PBB in humans, a cohort of PBB-exposed Michigan residents was assembled in 1975. We initiated this study to determine the half-life of PBB in human sera and to understand how continued body burden relates to the possible adverse health consequences of PBB exposure. To determine the half-life, eligible persons were selected from the cohort if they had at least two PBB measurements 1 year apart and had an initial level > or = 20 pbb. There were 163 persons who met the criteria with a median PBB level of 45.5 ppb. The estimated half-life is 10.8 years (95% CI, 9.2-14.7 years). The body burden of PBB in exposed persons will decrease only gradually over time. For persons with an initial level of 45.5 ppb of PBB, it will take more than 60 years for their PBB levels to fall below the current level of detection of 1 ppb.

Exposure to biogenic silica fibers and respiratory health in Hawaii sugarcane workers.

We conducted a cross-sectional environmental and medical survey of 355 male sugarcane workers in Hawaii to determine whether exposure to biogenic silica fibers (BSF) affected their respiratory health. Exposures to BSF ranged from nondetectable to more than 0.700 BSF/mL and varied by job and department. Respiratory symptoms, chest radiograph findings, and pulmonary function were not associated with BSF exposures. Cigarette smoking was associated with respiratory symptoms and pulmonary obstruction. Fifteen workers had pleural thickening or pleural plaques and 3 of these workers were exposed to BSF for more than 10 years. BSF exposure does not appear to influence the respiratory health of sugarcane workers; however, further study is warranted.

A case-control study of mesothelioma and employment in the Hawaii sugarcane industry.

We conducted a case-control study of 93 mesothelioma cases and 281 cancer controls to determine whether sugarcane workers exposed to biogenic silica fibers were at increased risk of mesothelioma. We found no important excess risk of mesothelioma in sugarcane workers [odds ratio (OR) = 1.3; 95% confidence interval (CI) = 0.4-3.8] when we excluded all control subjects with cancer of sites suspected of being associated with asbestos exposure. We could not identify any sugarcane workers who developed mesothelioma and worked in jobs where high exposure levels of biogenic silica fibers have been measured. We did confirm that mesothelioma risk in Hawaii is associated with probable occupational asbestos exposure. Work at the Pearl Harbor Naval Shipyard was associated with a 10-fold increase in mesothelioma when we excluded controls with cancer of sites related to asbestos exposure (OR = 10.1; 95% CI = 2.6-56.6). Work in the medical industry was also associated with an unexpected increased risk for mesothelioma (OR = 4.2; 95% CI = 1.2-15.5).