The beryllium bronchoalveolar lavage lymphocyte proliferation test: indicator of beryllium sensitization, inflammation or both?

CONTEXT

We had available records on over 300 workers evaluated with the beryllium bronchoalveolar lavage lymphocyte proliferation test (BeBALLPT) at three expert chronic beryllium disease (CBD) diagnostic centers.

OBJECTIVE

The objective was to describe the contribution of the BeBALLPT to classification of workers with respect to beryllium sensitization (BeS) and beryllium-induced lung inflammation.

METHODS

Company records were used to identify beryllium workers who had undergone diagnostic bronchoscopy with BeBALLPT. Clinical, work and smoking information was abstracted from electronic and paper databases. We analyzed factors influencing BeBALLPT outcome, and its relation to blood-determined BeS and granulomatous inflammation.

RESULTS

Positive BeBALLPTs contributed evidence of BeS in subjects without prior positive beryllium blood lymphocyte proliferation tests (BeBLPTs) and of pulmonary inflammation in persons without granulomata evident on lung biopsy. Positive BeBALLPTs were associated with positive BeBLPTs and more strongly with granulomata. The rate of both positive BeBALLPT and granulomata increased with time worked through 4 years and were lower in smoking subjects. The false negative rate of the BeBALLPT was 20%.

CONCLUSION

A positive BeBALLPT is closely linked to the presence of granulomata on lung biopsy and can be considered as an indicator of lung inflammation in addition to BeS. The ability to use BeBALLPT as a substitute for the more risky lung biopsy is limited by the BeBALLPT false negative rate and lack of information on the false positive rate. It is not recommended that a positive BeBALLPT be considered sufficient evidence for both lung inflammation and BeS.

Occupational Cohort Time Scales

PURPOSE

This study explores how highly correlated time variables (occupational cohort time scales) contribute to confounding and ambiguity of interpretation.

METHODS

Occupational cohort time scales were identified and organized through simple equations of three time scales (relational triads) and the connections between these triads (time scale web). The behavior of the time scales was examined when constraints were imposed on variable ranges and interrelationships.

RESULTS

Constraints on a time scale in a triad create high correlations between the other two time scales. These correlations combine with the connections between relational triads to produce association paths. High correlation between time scales leads to ambiguity of interpretation.

CONCLUSIONS

Understanding the properties of occupational cohort time scales, their relational triads, and the time scale web is helpful in understanding the origins of otherwise obscure confounding bias and ambiguity of interpretation.

Implications of common and special variation for occupational health: examples from beryllium manufacturing

OBJECTIVE

Common variation is a statistical process-control term for variability associated with usual operating conditions. Special variation occurs when usual operating conditions are disrupted. The objective was to explore the implications for preventive occupational medicine practice of common and special variation in air-level exposure.

METHODS

Illustrations are derived from US and UK beryllium facility databases.

RESULTS

Special variation may be missed in finite sampling sets, giving a very inaccurate indication of the highest air levels experienced on the job. Depending on the toxicologic model, failure to assess special variation influences the meaningfulness of aspects of occupational prevention, from medical surveillance through risk management.

CONCLUSIONS

Jobs and tasks should be characterized for special variation in addition to traditional air sampling. Both special variation and common variation should be considered in occupational medicine preventive practice.

Migration of Beryllium via Multiple Exposure Pathways among Work Processes in Four Different Facilities

Inhalation of beryllium is associated with the development of sensitization; however, dermal exposure may also be important. The primary aim of this study was to elucidate relationships among exposure pathways in four different manufacturing and finishing facilities. Secondary aims were to identify jobs with increased levels of beryllium in air, on skin, and on surfaces; identify potential discrepancies in exposure pathways, and determine if these are related to jobs with previously identified risk. Beryllium was measured in air, on cotton gloves, and on work surfaces. Summary statistics were calculated and correlations among all three measurement types were examined at the facility and job level. Exposure ranking strategies were used to identify jobs with higher exposures. The highest air, glove, and surface measurements were observed in beryllium metal production and beryllium oxide ceramics manufacturing jobs that involved hot processes and handling powders. Two finishing and distribution facilities that handle solid alloy products had lower exposures than the primary production facilities, and there were differences observed among jobs. For all facilities combined, strong correlations were found between air-surface (rp ≥ 0.77), glove-surface (rp ≥ 0.76), and air-glove measurements (rp ≥ 0.69). In jobs where higher risk of beryllium sensitization or disease has been reported, exposure levels for all three measurement types were higher than in jobs with lower risk, though they were not the highest. Some jobs with low air concentrations had higher levels of beryllium on glove and surface wipe samples, suggesting a need to further evaluate the causes of the discrepant levels. Although such correlations provide insight on where beryllium is located throughout the workplace, they cannot identify the direction of the pathways between air, surface, or skin. Ranking strategies helped to identify jobs with the highest combined air, glove, and/or surface exposures. All previously identified high-risk jobs had high air concentrations, dermal mass loading, or both, and none had low dermal and air. We have found that both pathways are relevant. [Supplementary materials are available for this article. Go to the publisher's online edition of Journal of Occupational and Environmental Hygiene for the following free supplemental resource: a file describing the forms of beryllium materials encountered during production and characteristics of the aerosols by process areas.].

Long-term efficacy of a program to prevent beryllium disease

BACKGROUND

In 2000, a manufacturer of beryllium materials and products introduced a comprehensive program to prevent beryllium sensitization and chronic beryllium disease (CBD). We assessed the program's efficacy in preventing sensitization 9 years after implementation.

METHODS

Current and former workers hired since program implementation completed questionnaires and provided blood samples for the beryllium lymphocyte proliferation test (BeLPT). Using these data, as well as company medical surveillance data, we estimated beryllium sensitization prevalence.

RESULTS

Cross-sectional prevalence of sensitization was 0.7% (2/298). Combining survey results with surveillance results, a total of seven were identified as sensitized (2.3%). Early Program workers were more likely to be sensitized than Late Program workers; one of the latter was newly identified. All sensitization was identified while participants were employed. One worker was diagnosed with CBD during employment.

CONCLUSIONS

The combination of increased respiratory and dermal protection, enclosure and improved ventilation of high-risk processes, dust migration control, improved housekeeping, and worker and management education showed utility in reducing sensitization in the program's first 9 years. The low rate (0.6%, 1/175) among Late Program workers suggests that continuing refinements have provided additional protection against sensitization compared to the program's early years.

Long-term follow-up of beryllium sensitized workers from a single employer

Background

Up to 12% of beryllium-exposed American workers would test positive on beryllium lymphocyte proliferation test (BeLPT) screening, but the implications of sensitization remain uncertain.

Methods

Seventy two current and former employees of a beryllium manufacturer, including 22 with pathologic changes of chronic beryllium disease (CBD), and 50 without, with a confirmed positive test were followed-up for 7.4 +/-3.1 years.

Results

Beyond predicted effects of aging, flow rates and lung volumes changed little from baseline, while D_LCO dropped 17.4% of predicted on average. Despite this group decline, only 8 subjects (11.1%) demonstrated physiologic or radiologic abnormalities typical of CBD. Other than baseline status, no clinical or laboratory feature distinguished those who clinically manifested CBD at follow-up from those who did not.

Conclusions

The clinical outlook remains favorable for beryllium-sensitized individuals over the first 5-12 years. However, declines in D_LCO may presage further and more serious clinical manifestations in the future. These conclusions are tempered by the possibility of selection bias and other study limitations.

Efficacy of a program to prevent beryllium sensitization among new employees at a copper-beryllium alloy processing facility

OBJECTIVES

In 2000, 7% of workers at a copper-beryllium facility were beryllium sensitized. Risk was associated with work near a wire annealing/pickling process. The facility then implemented a preventive program including particle migration control, respiratory and dermal protection, and process enclosure. We assessed the program's efficacy in preventing beryllium sensitization.

METHODS

In 2000, the facility began testing new hires (program workers) with beryllium lymphocyte proliferation tests (BeLPTs) at hire and at intervals during employment. We compared sensitization incidence rates (IRs) and prevalence rates for workers hired before the program (legacy workers) with rates for program workers, including program worker subgroups. We also examined trends in BeLPTs from a single laboratory.

RESULTS

In all, five of 43 legacy workers (IR = 3.8/1,000 person-months) and three of 82 program workers (IR = 1.9/1,000 person-months) were beryllium sensitized, for an incidence rate ratio (IRR) of 2.0 (95% confidence interval [CI] 0.5, 10.1). Two of 37 pre-enclosure program workers (IR = 2.4/1,000 person-months) and one of 45 post-enclosure program workers (IR = 1.4/1,000 person-months) were beryllium sensitized, for IRRs of 1.6 (95% CI 0.3, 11.9) and 2.8 (95% CI 0.4, 66.2), respectively, compared with legacy workers. Test for trend in prevalence rates was significant. Among 2,159 first-draw BeLPTs during 95 months, we identified seven months when high numbers of redraws were required, with one possible misclassification in this facility.

CONCLUSIONS

Fewer workers became sensitized after implementation of the preventive program. However, low statistical power due to the facility's small workforce prevents a definitive conclusion about the program's efficacy. These findings have implications for other copper-beryllium facilities, where program components may merit application.

Assessment of the Beryllium Lymphocyte Proliferation Test Using Statistical Process Control

Despite more than 20 years of surveillance and epidemiologic studies using the beryllium blood lymphocyte proliferation test (BeBLPT) as a measure of beryllium sensitization (BeS) and as an aid for diagnosing subclinical chronic beryllium disease (CBD), improvements in specific understanding of the inhalation toxicology of CBD have been limited. Although epidemiologic data suggest that BeS and CBD risks vary by process/work activity, it has proven difficult to reach specific conclusions regarding the dose-response relationship between workplace beryllium exposure and BeS or subclinical CBD. One possible reason for this uncertainty could be misclassification of BeS resulting from variation in BeBLPT testing performance. The reliability of the BeBLPT, a biological assay that measures beryllium sensitization, is unknown. To assess the performance of four laboratories that conducted this test, we used data from a medical surveillance program that offered testing for beryllium sensitization with the BeBLPT. The study population was workers exposed to beryllium at various facilities over a 10-year period (1992-2001). Workers with abnormal results were offered diagnostic workups for CBD. Our analyses used a standard statistical technique, statistical process control (SPC), to evaluate test reliability. The study design involved a repeated measures analysis of BeBLPT results generated from the company-wide, longitudinal testing. Analytical methods included use of (1) statistical process control charts that examined temporal patterns of variation for the stimulation index, a measure of cell reactivity to beryllium; (2) correlation analysis that compared prior perceptions of BeBLPT instability to the statistical measures of test variation; and (3) assessment of the variation in the proportion of missing test results and how time periods with more missing data influenced SPC findings. During the period of this study, all laboratories displayed variation in test results that were beyond what would be expected due to chance alone. Patterns of test results suggested that variations were systematic. We conclude that laboratories performing the BeBLPT or other similar biological assays of immunological response could benefit from a statistical approach such as SPC to improve quality management.

Empirical evaluation of complex epidemiologic study designs: workplace exposure and cancer

OBJECTIVE

To test whether a frequently used cohort-nested case-control study design exaggerated exposure-response relationships because of unrecognized study design bias. Our aim was to evaluate empirically the performance of this complex study design.

METHODS

We applied the design from one such study to a closely related cohort using randomly selected probands as cases. Values for average exposures were assigned to probands equal to, greater than, and less than those assigned to controls (matches).

RESULTS

Under certain lag scenarios, the nested study design produced higher average exposure in probands compared with their matches, even when this was clearly not the case.

CONCLUSIONS

Empirical evaluation demonstrated that the study design produced a biased case-control lagged exposure difference under the null hypothesis and could not distinguish qualitatively between null and alternate hypotheses. Empirical evaluation provided a useful check on results generated from a complex study design. It gave useful insight into the behavior of the index study design that was not otherwise readily deducible.

Exposure to beryllium and occurrence of lung cancer: a reexamination of findings from a nested case-control study

OBJECTIVE

Our aim was to reanalyze a nested case-control study of beryllium and lung cancer because we identified analysis and study design issues that could have led to the elevated odds ratios obtained in the study.

METHODS

We reanalyzed the data using nontransformed exposure metrics instead of log-transformed metrics used in the publication. We identified and examined effects on estimated odds ratios of imbalances between cases and controls caused by the control selection method.

RESULTS

This reanalysis found no elevated odds ratios for any exposure variable.

CONCLUSION

: Our conclusions differ from the authors' interpretation that the findings are due to a causal relationship between beryllium exposure and lung cancer. Our alternative explanation is that they may be due to methodological problems that could have been controlled by closer matching of controls to cases.

CLINICAL SIGNIFICANCE

This study challenges conclusions made from a large case-control study concerning beryllium-lung cancer associations. Occupational medicine practitioners may want to integrate findings from this study into advice they give beryllium-exposed workers concerned about lung cancer.

Enhanced preventive programme at a beryllium oxide ceramics facility reduces beryllium sensitisation among new workers

BACKGROUND

A 1998 survey at a beryllium oxide ceramics manufacturing facility found that 10% of workers hired in the previous 6 years had beryllium sensitisation as determined by the beryllium lymphocyte proliferation test (BeLPT). In response, the facility implemented an enhanced preventive programme to reduce sensitisation, including increased respiratory and dermal protection and particle migration control.

AIM

To assess the programme's effectiveness in preventing sensitisation.

METHODS

In 2000, the facility began testing newly hired workers for beryllium sensitisation with the BeLPT at time of hire and during employment. The sensitisation rate and prevalence for workers hired from 2000 to 2004 were compared with that for workers hired from 1993 to 1998, who were tested in the 1998 survey. Facility environmental conditions for both time periods were evaluated.

RESULTS

Newly hired workers in both cohorts worked for a mean of 16 months. Of the 97 workers hired from 2000 to 2004 with at least one employment BeLPT result, four had abnormal results at time of hire and one became sensitised during employment. Of the 69 workers hired from 1993 to 1998 and tested in 1998, six were found to be sensitised. The sensitisation rate for the 2000-4 workers was 0.7-2.7/1000 person-months of employment, and that for the 1993-8 workers was 5.6/1000 person-months, at least 2.1 (95% confidence interval (CI) 0.6 to 8.4) and up to 8.2 (95% CI 1.2 to 188.8) times higher than that for the 2000-4 workers. The sensitisation prevalence for the 2000-4 workers was 1% and that for the 1993-8 workers was 8.7%, 8.4 (95% CI 1.04 to 68.49) times higher than that for the 2000-4 workers. Airborne beryllium levels for production workers for the two time periods were similar.

CONCLUSIONS

A comprehensive preventive programme reduced beryllium sensitisation in new workers during the first years of employment, despite airborne beryllium levels for production workers that were similar to pre-programme levels.

Exposure Pathway Assessment at a Copper–Beryllium Alloy Facility

Controlling beryllium inhalation exposures to comply with regulatory levels (2 micro g m(-3) of air) does not appear to prevent beryllium sensitization and chronic beryllium disease (CBD). Additionally, it has proven difficult to establish a clear inhalation exposure-response relationship for beryllium sensitization and CBD. Thus, skin may be an important route of exposure that leads to beryllium sensitization. A 2000 survey had identified prevalence of sensitization (7%) and CBD (4%) in a beryllium alloy facility. An improved particulate migration control program, including dermal protection in production areas, was completed in 2002 at the facility. The purpose of this study was to evaluate levels of beryllium in workplace air, on work surfaces, on cotton gloves worn by employees over nitrile gloves, and on necks and faces of employees subsequent to implementation of the program. Over a 6 day period, we collected general area air samples (n = 10), wipes from routinely handled work surfaces (n = 252), thin cotton glove samples (n = 113) worn by employees, and neck wipes (n = 109) and face wipes (n = 109) from the same employees. In production, production support and office areas geometric mean (GM) levels of beryllium were 0.95, 0.59 and 0.05 micro g per 100 cm(2) on work surfaces; 42.8, 73.8 and 0.07 micro g per sample on cotton gloves; 0.07, 0.09 and 0.003 micro g on necks; and 0.07, 0.12 and 0.003 micro g on faces, respectively. Correlations were strong between beryllium in air and on work surfaces (r = 0.79), and between beryllium on cotton gloves and on work surfaces (0.86), necks (0.87) and faces (0.86). This study demonstrates that, even with the implementation of control measures to reduce skin contact with beryllium as part of a comprehensive workplace protection program, measurable levels of beryllium continue to reach the skin of workers in production and production support areas. Based on our current understanding of the multiple exposure pathways that may lead to sensitization, we support prudent control practices such as use of protective gloves to minimize skin exposure to beryllium salts and fine particles.

Sensitization and Chronic Beryllium Disease Among Workers in Copper???Beryllium Distribution Centers

OBJECTIVE

Little is known about the risk of sensitization and chronic beryllium disease (CBD) among workers performing limited processing of copper-beryllium alloys downstream of the primary beryllium industry. In this study, we performed a cross-sectional survey of employees at three copper-beryllium alloy distribution centers.

METHODS

One hundred workers were invited to be tested for beryllium sensitization using the beryllium blood lymphocyte proliferation test (BeLPT); a sensitized worker was further evaluated for CBD. Available beryllium mass concentration air sampling data were obtained for characterization of airborne exposure.

RESULTS

One participant, who had exposure to other forms of beryllium, was found to be sensitized and to have CBD, resulting in a prevalence of sensitization/CBD of 1% for all tested.

CONCLUSIONS

The overall prevalence of beryllium sensitization and CBD for workers in these three copper-beryllium alloy distribution centers is lower than for workers in primary beryllium production facilities.

Process-related risk of beryllium sensitization and disease in a copper-beryllium alloy facility

BACKGROUND

Chronic beryllium disease (CBD), which primarily affects the lungs, occurs in sensitized beryllium-exposed individuals. At a copper-beryllium alloy strip and wire finishing facility we performed a cross-sectional survey to examine prevalences of beryllium sensitization and CBD, and relationships between sensitization and CBD and work areas/processes.

METHODS

Current employees (185) were offered beryllium lymphocyte proliferation testing (BeLPT) for sensitization, clinical evaluation for CBD (if sensitized), and questionnaires. We obtained historical airborne beryllium measurements.

RESULTS

Participation was 83%. Prevalences of sensitization and CBD were 7% (10/153) and 4% (6/153), respectively; this included employees with abnormal BeLPTs from two laboratories, four diagnosed with CBD during the survey, and one each diagnosed preceding and following the survey. Potential BeLPT laboratory problems were noted; one laboratory was twice as likely to have reported an abnormal result (P < 0.05, all tests), and five times as likely to have reported a borderline or uninterpretable result (P < 0.05, first blood draw and all tests). CBD risk was highest in rod and wire production (P < 0.05), where air levels were highest.

CONCLUSIONS

Sensitization and CBD were associated with an area in which beryllium air levels exceeded 0.2 microg/m3, and not with areas where this level was rarely exceeded. Employees at this copper-beryllium alloy facility had similar prevalences of sensitization and CBD as workers at facilities with higher beryllium air levels.

Major histocompatibility locus genetic markers of beryllium sensitization and disease

Hypersensitivity to beryllium (Be) is found in 1-16% of exposed workers undergoing immunological screening for beryllium disease using the beryllium lymphocyte proliferation test (BeLPT). However, only approximately 50% of BeLPT-positive workers present with lung granulomas (i.e. berylliosis). As berylliosis is associated with the human leukocyte antigen (HLA)-DP supratypic marker DPGlu69, the authors asked whether this marker is differentially associated with disease presentation. A population of 639 workers from a beryllium factory undergoing BeLPT screening was evaluated in a nested case-control study for the prevalence of HLA-DPGlu69, the HLA-DPB1, HLA-DQ and HLA-DR alleles and of the biallelic tumour necrosis factor (TNF)-alpha polymorphism TNF-alpha-308 in 23 individuals presenting as "sensitized" (i.e. BeLPT-positive without lung granulomas) and in 22 presenting as "diseased" (i.e. BeLPT-positive with granulomas in the lung biopsy). The HLA-DPGlu69 marker was associated with "disease" (odds ratio (OR) 3.7, p=0.016, 95% confidence interval (CI) 1.4-10.0), whilst the high TNF-alpha production-related TNF-alpha-308*2 marker was associated with both a positive BeLPT (OR 7.8, corrected p<0.0001, 95% CI 3.2-19.1) with no difference between "sensitization" and "disease". Furthermore, the HLA-DRArg74 marker was associated with "sensitization" without disease (OR 3.96, p=0.005, 95%, CI 1.5-10.1). The data indicate that tumour necrosis factor-alpha, human leukocyte antigen-DR and human leukocyte antigen-DP markers play different roles in beryllium sensitization and granuloma formation in beryllium-exposed workers.

Variability, Predictive Value, and Uses of the Beryllium Blood Lymphocyte Proliferation Test (BLPT): Preliminary Analysis of the Ongoing Workforce Survey

The beryllium blood lymphocyte proliferation test (BLPT) is used as a medical surveillance tool for assessment of persons at risk for developing clinical and subclinical chronic beryllium disease (CBD). Three laboratories, coded "A," "B," and "C," were used to perform the BLPTs, which involved two simultaneous tests on a split specimen. The intra-laboratory agreement analysis compared the first and the second test performed by the same laboratory. The interlaboratory agreement analysis compared test results performed by different laboratories on the same sample. The level of agreement was expressed as a kappa statistic. The positive predictive value (PPV) analysis compared BLPT results against the results of a bronchoscopy used to detect CBD. The data included 5483 records representing 3081 samples from 1510 persons. Intra-laboratory agreement was fair to moderate, with kappa values between 0.3 and 0.6. Inter-laboratory agreement was moderate (kappa = 0.5) for Labs A and B, moderate (kappa = 0.6) for Labs B and C, and poor (kappa = 0.2) for Labs A and C. A single unconfirmed abnormal test had a PPV for CBD of 39 percent, a confirmed (based on subsequent testing) abnormal test had a PPV for CBD of 45 percent, and a first-time double abnormal test had a PPV for CBD of 49 percent. Substantial inter- and intralaboratory disagreement exists between and within major laboratories that conduct this test.

Contribution of Incidental Exposure Pathways to Total Beryllium Exposures

Beryllium manufacturing processes are associated with the immune-mediated chronic beryllium disease (CBO). Recent workplace epidemiological studies have been relatively unsuccessful in correlating disease with workplace air concentrations of beryllium, thereby failing to support the hypothesis that dose by the respiratory route determines the risk of disease. This has led to consideration of the hypotheses that dermal or oral exposures to beryllium can influence disease risk, either as a cause of sensitization or to induced tolerance to beryllium. If so, the control of dermal and/or ingestion exposure to beryllium, which has heretofore been widely disregarded in the United States, would be of practical importance. Most of the literature of the past 50 years indicates that ingestion and dermal uptake of beryllium are unimportant routes of exposures. The toxicology data generally support this position. However, research is under way to determine whether sensitization to beryllium may occur following exposure via routes other than inhalation, raising the question of whether this sensitization from other routes of exposure makes the lungs more susceptible to inflammation when inhaled doses are encountered. Using published data on other metals, this article describes the likely range of doses that a worker might incur in the workplace due to incidental exposure pathways (i.e., exposures not directly related to inhalation of workplace air), such as hand-to-mouth exposure, dermal contact, and resuspension following deposition of beryllium onto clothing. This analysis indicates that these incidental routes of exposure could contribute to total absorbed doses of beryllium that exceed simple airborne inhalation exposures. Because the doses presented by these alternative exposure pathways could be appreciable compared with the airborne inhaled dose, and could continue even when respirators are worn, these pathways may represent the primary routes of entry of beryllium into the body. We believe that the potential for exposure from these incidental exposure pathways merits additional study.

Cigarette smoking, alcohol consumption, and breast cancer risk

The effects of cigarette smoking and alcohol consumption on breast cancer risk were investigated in 276 primary, histologically confirmed breast cancer patients and 1,519 community-based comparison subjects identified in 1977 and 1978 in North Carolina. Data on both behaviors and other pertinent personal and medical characteristics were obtained by interview. Analytic methods included stratification and logistic regression. Among current cigarette smokers of 1-20 cigarettes per day and over 20 per day, the odds ratios (ORs) adjusted for age, race, alcohol consumption, estrogen use, and oral contraceptive use for breast cancer were 0.75 [95% confidence interval (CI) 0.52-1.09] and 0.57 (95% CI 0.30-1.08), respectively. A decrease in risk was not seen in former smokers. With respect to alcohol consumption, the adjusted OR for those having one drink or more per week compared to those having less than one was 1.45 (95% CI 0.99-2.12). If the comparison was ever versus never drinkers, the adjusted OR was 1.47 (95% CI 1.10-1.97); for current drinkers versus nondrinkers, the adjusted OR was 1.89 (95% CI 1.40-2.56). The ORs were adjusted for age, race, cigarette smoking, estrogen use, an oral contraceptive use. These data supports those reports showing an inverse association of cigarette smoking and a positive association of alcohol consumption with breast cancer risk.

One-time screening to define the problem: Legionella exposure in an electric power company

An electric utility screened 1,455 production employees for job exposure to Legionella pneumophila sources, illness history, and antibodies to L pneumophila serotypes I-IV. L pneumophila-associated illness outbreaks had occurred in a neighboring electric utility district; bacteria serocompatible with L pneumophila had been detected in all four plants participating in an environmental survey, and the company was concerned about the implications of these findings for their employees and the public living near power plants with large cooling towers. The survey revealed a prevalence of antibodies in employees consistent with general population surveys. Within the employee group, antibody titer was not associated with either reports of recent illness or work exposure to potential L pneumophila sources. Inability to detect a relationship between exposure to potential L pneumophila sources and specific antibody results was used to define L pneumophila as a historic nonproblem for this company and to rationally advise against the need for an ongoing screening program.

Hormonal and personal effects on estrogen receptors in breast cancer

Since high estrogen receptor protein in breast cancer tissue has a favorable effect on patient prognosis, factors influencing estrogen receptor levels are the focus of this research. From April 1977 to December 1978, 246 histologically confirmed primary breast cancer patients from three North Carolina hospitals were interviewed and provided with photographic displays of hormonal products. Their tumor tissue was analyzed for estrogen receptor protein by the sucrose density gradient assay. Data were analyzed by multiple regression and logistic regression techniques. No statistically significant relationship was found between gonadal hormone usage and estrogen receptor levels, although recent users of either oral contraceptives or replacement estrogens had lower receptor levels. Users of progestogen-predominant and -intermediate types of oral contraceptives also had lower estrogen receptor protein. An effect of menopausal status, independent of age, was not evident. Statistically significant associations involved age and race among postmenopausal patients. With black breast cancer patients aged less than 70 years as the reference group, the relative odds of having high estrogen receptor protein (greater than 10 fmol/mg of cytosol protein) were 2.4 times greater among whites aged less than 70, 1.6 times greater in blacks aged greater than or equal to 70, and 12.8 times greater in whites greater than or equal to 70 years. These differences in estrogen receptor protein may contribute to the black-white differential in breast cancer survival.

Breast cancer and estrogen replacement therapy

Concern over the possible effect of estrogen replacement therapy on the subsequent development of breast cancer prompted us to compare 199 postmenopausal breast cancer patients with 451 hospital control subjects and 852 community control subjects on their prior use of estrogens. Estrogen use did not increase the breast cancer risk for women with a surgical menopause. Among women with a natural menopause, estrogens administered by all routes were associated with breast cancer risks of 1.7 of 1.8. There was no coherent pattern of changing risks with varying durations of use, different daily dosages, years since first use of estrogen, or years since most recent use. When women who usually received estrogen by injection were excluded, the risk estimates for oral estrogens were 1.3 (case subjects compared to community control subjects) and 1.2 (case subjects compared to hospital control subjects). These increases were not statistically significant. Use of injectable estrogens produced a fourfold increase in breast cancer risk among naturally postmenopausal women.

Logistic model estimation of death attributable to risk factors for cardiovascular disease in Evans County, Georgia

Linear logistic analysis of the relationship of cardiovascular disease risk factors to an overall measure of health effect, ten-year mortality, revealed significant associations of death with systolic blood pressure, age, sex, diabetes mellitus, smoking, cholesterol, obesity (Quetelet index), race and social index. Attributable risk and population attributable risk estimates were derived from the model by changing actual variable values to target values. The results confirmed systolic hypertension and smoking as major public health problems and diabetes mellitus as a powerful risk factor for death. The small detrimental effect of cholesterol on probability of death limits the potential for an overall beneficial effect of preventive intervention. In fact, drug intervention in two reported trials of cholesterol reduction had negative overall effects. Demonstration of the association of a characteristic with a specific disease state does not alone justify attempts to eliminate the high risk state from a population. An overall detrimental health effect must be documented by suitable studies before trials of preventive intervention are undertaken or recommendations made to the public.

Nonpneumonic, short-incubation-period Legionellosis (Pontiac fever) in men who cleaned a steam turbine condenser

Pontiac fever affected ten men who had cleaned a steam turbine condenser with compressed air. Previous epidemics of Pontiac fever and Legionnaires' disease--both caused by Legionella Pneumophila (proposed sp. nov.)--involved "airborne spread" from air-conditioning cooling towers or evaporative condensers. Aerosols of contaminated water in heat-rejection systems appear to be important sources of epidemic legionellosis.

Fever of undetermined etiology after cleaning of steam turbine condensers

Two outbreaks of a febrile syndrome marked by chills, headaches, myalgia, nausea, and malaise occurred in workers who had cleaned the steam condensers of electric power turbines. Mean incubation period was 38 hours. Twenty-two of twenty-three exposed men became ill. Clinical and environmental investigation failed to reveal the etiology of the outbreaks. The circumstances and clinical syndrome have points of similarity to fever following inhalation of metal fumes and low-grade, stained cotton dust, and to Pontiac fever.

Attributable risk, population attributable risk, and population attributable fraction of death associated with hypertension in a biracial population

In 1961, blood pressure was measured in the 40-69-year-old segment of the population of Evans County, Georgia. Mortality was monitored for up to ten years. The relationship found between hypertension and mortality is characterized in this report by four parameters: attributable risk, prevalence, population attributable risk, and population attributable fraction. Attributable risk of death, a measure of the over-all impact of hypertension on those in each race-sex group with hypertension, is high in white males, black males, and black females, and is lowest in white females. Population attributable risk, a measure of the impact of hypertension on each entire race-sex group, is highest in black males and females due to the high prevalence of hypertension in blacks. It is somewhat lower in white males and lowest in white females. The fraction of all deaths attributable to hypertension (population attributable fraction) is highest in black females and lower in the other three groups. The population attributable fraction (ranging from 0.26 to 0.54 for systolic hypertension) is of such magnitude that if the 50% reduction in mortality achieved in the Veteran Administration Cooperative Study could be repeated in the general population, life expectancy after 40 years of age could be substantially increased.