Mining, handling, processing, and personal or commercial use of asbestos-contaminated vermiculite have led to widespread contamination of the Libby, Montana, area. We initiated a medical testing program in response to reports of respiratory illness in the community. The purpose of this analysis was to identify and quantify asbestos-related radiographic abnormalities among persons exposed to vermiculite in Libby and to examine associations between these outcomes and participants' self-reported exposures. A cross-sectional interview and medical testing were conducted in Libby from July through November 2000 and from July through September 2001. A total of 7,307 persons who had lived, worked, or played in Libby for at least 6 months before 31 December 1990 completed the interview. Of those, 6,668 participants ≥ 18 years of age received chest radiographs to assess the prevalence of pleural and interstitial abnormalities. We observed pleural abnormalities in 17.8% of participants and interstitial abnormalities in < 1% of participants undergoing chest radiography. We examined 29 occupational, recreational, household, and other exposure pathways in the analysis. The prevalence of pleural abnormalities increased with increasing number of exposure pathways, ranging from 6.7% for those who reported no apparent exposures to 34.6% for those who reported ≥ 12 pathways. The factors most strongly associated with pleural abnormalities were being a former W.R. Grace worker, being older, having been a household contact of a W.R. Grace worker, and being a male. In addition to being a former W.R. Grace worker, environmental exposures and other nonoccupational risk factors were also important predictors of asbestos-related radiographic abnormalities.

No abstract

Background: Individuals with monoclonal B-cell lymphocytosis (MBL) have been identified in clinic outpatients, in unaffected relatives of patients with chronic lymphocytic leukemia (CLL), and in general populations. MBL and its relationship with CLL have been actively investigated over the last decade. This report systematically reviews the prevalence of MBL in the context of the populations studied and the evolution of laboratory methods used to define MBL. Methods: To identify published studies that have assessed the prevalence of MBL, we systematically searched the MEDLINE V R databases and consulted with members of the International MBL Study Group. We reviewed the 10 articles that were identified by this process. We abstracted information on study populations, laboratory tests, criteria for designating MBL, and the reported frequencies.Results

Importance Multiple myeloma has been classified as exhibiting “limited or suggestive evidence” of an association with exposure to herbicides in Vietnam Veterans. Occupational studies have shown that other pesticides (i.e., insecticides, herbicides, fungicides) are associated with excess risk of multiple myeloma (MM) and its precursor state, monoclonal gammopathy of undetermined significance (MGUS); however no studies have uncovered such an association in Vietnam Veterans. Objective To examine the relationship between MGUS and exposure to Agent Orange, including its contaminant 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), in Vietnam Veterans. Design Our study is a prospective cohort study, testing for MGUS in serum specimens collected and stored in 2002 by the Air Force Health Study (AFHS). The relevant exposure data collected by the AFHS was also used. We tested all specimens in 2013 without knowledge of the exposure status. The AFHS included former US Air Force personnel who participated in Operation Ranch Hand (Ranch Hand Veterans) and other US Air Force personnel who had similar duties in Southeast Asia during the same time period but were not involved in herbicide spray missions (comparison Veterans). Setting Agent Orange was used by the US Air Force personnel who conducted aerial spray missions of herbicides (Operation Ranch Hand) in Vietnam from 1962–1971. Participants We included 479 Ranch Hand Veterans and 479 comparison Veterans who participated in the 2002 follow-up examination of AFHS. Exposure Agent Orange and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD, a contaminant of Agent Orange). Serum TCDD levels were measured in 1987, 1992, 1997, and 2002. Main Outcomes and Measures Risk of MGUS measured by prevalence, odds ratios (OR), and 95% confidence intervals (CI). Results The prevalence of MGUS in Ranch Hand Veterans (7.1%) was higher than in comparison Veterans (3.1%) (adjusted OR=2.37, 95% CI, 1.27–4.44; P=0.007). The cohort status was significantly (P=0.0001) associated with TCDD levels: 47% of Ranch Hand Veterans had serum TCDD levels >10.92 ppt compared to 2.5% of comparison Veterans. Conclusions and Relevance Ranch Hand Veterans have a significantly increased risk of MGUS, supporting an association between Agent Orange exposure and multiple myeloma.

This analysis examined associations between total reduced sulfur (TRS) and hydrogen sulfide (H 2 S) levels, and hospital visits for respiratory disease among residents of Dakota City and South Sioux City, Nebraska, from January 1998 to May 2000. For reference, the association between TRS, H 2 S, and digestive diseases was also examined. Time-series analyses of daily hospital visits in the selected outcome categories and measures of TRS and H 2 S were performed using generalized additive models with a Poisson link. TRS and H 2 S levels were categorized as high if at least one of the daily 30-min rolling averages was Z30 ppb and as low if every rolling average was o30 ppb. Loess smoothers allowed for flexible modeling of the time effect and the effect of temperature and relative humidity. The measure of association used was the mean percent change in the average number of hospital visits recorded following a day with a high exposure versus a day with a low exposure. For children less than 18 years of age, a positive association was found between asthma hospital visits and 1-day lagged TRS levels. For adults, a positive association was found between asthma hospital visits and H 2 S levels on the previous day. A positive association also was found between hospital visits for all respiratory diseases, and H 2 S and TRS levels on the previous day for children but not for adults. No association was found between contaminant levels and hospital visits for all digestive diseases. These findings suggest that TRS or H 2 S levels may be associated with exacerbations of asthma or other respiratory diseases among the residents of Dakota City and South Sioux City.

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.

A priori characterization of the testing algorithm under consideration can enhance public health decision-making.

SummaryThe first studies of monoclonal B-cell lymphocytosis (MBL) in the general population were conducted as part of environmental health investigations that began in 1991. MBL was observed as an unexpected finding when blood samples were immunophenotyped by two-colour flow cytometric methods in common use at that time. The initial observations led to a workshop in 1995, at which case definitions were considered and medical follow-up investigations were recommended. Medical follow-ups were conducted in 1997 and 2003. A total of eight cases of confirmed MBL and three cases of presumptive MBL were identified. This review summarizes the findings from those investigations and discusses the issues related to using MBL as a biomarker in environmental health research and population-based studies.