ABSTRACT
Fine particulate matter (PM2.5) air pollution exposure is associated with short and long-term health effects. Several studies found differences in PM2.5 exposure associated with neighborhood racial and socioeconomic composition. However, most focused on total PM2.5 mass rather than its chemical components and their sources. In this study, we describe the ZIP code characteristics that drive the disparities in exposure to PM2.5 chemical components attributed to source categories both nationally and regionally. We obtained annual mean predictions of PM2.5 and fourteen of its chemical components from spatiotemporal models and socioeconomic and racial predictor variables from the 2010 US Census, and the American Community Survey 5-year estimates. We used non-negative matrix factorization to attribute the chemical components to five source categories. We fit generalized nonlinear models to assess the associations between the neighborhood predictors and each PM2.5 source category in urban areas in the United States in 2010 (n=25,790 zip codes). We observed higher PM2.5 levels in ZIP codes with higher proportions of Black individuals and lower socioeconomic status. Racial exposure disparities were mainly attributed to Heavy Fuel, Oil and Industrial, Metal Processing Industry and Agricultural, and Motor Vehicle sources. Economic disparities were mainly attributed to Soil and Crustal Dust, Heavy Fuel Oil and Industrial, Metal Processing Industry and Agricultural, and Motor Vehicle sources. Upon further analysis through stratifying by regions within the United States, we found that the associations between ZIP code characteristics and source-attributed PM2.5 levels were generally greater in Western states. In conclusion, racial, socioeconomic, and geographic inequalities in exposure to PM2.5 and its components are driven by systematic differences in component sources that can inform air quality improvement strategies.
ABSTRACT
BACKGROUND: Bortezomib has significant activity in treating multiple myeloma (MM). The risk of herpes zoster (HZ) has been reported to increase significantly with bortezomib treatment, but the predisposing factors for HZ are not clear. This study is a retrospective analysis of the relevant risk factors for HZ in Korean MM patients treated with bortezomib. METHODS: Sixty-six patients with refractory or relapsed MM who underwent chemotherapy with bortezomib were included in the study. Prophylactic antiviral drugs were not used for treatment. The following parameters were reviewed: age, gender, stage and type of MM, extent of previous treatment, history of HZ, duration from the time of diagnosis to the time of bortezomib treatment initiation, and absolute lymphocyte counts (ALC) at the time of bortezomib treatment initiation. RESULTS: The incidence of HZ was 16.7%. There were no intergroup differences between the HZ-positive and the HZ-negative groups with regard to a history of HZ, number of previous treatments, and exposure to steroids before bortezomib treatment. The median duration from the time of MM diagnosis to the time of bortezomib treatment initiation in the HZ-positive group was significantly shorter than that in the HZ-negative group. The median ALC at the time of bortezomib initiation in the HZ-positive group was significantly lower than that in the HZ-negative group. CONCLUSION: Bortezomib itself might act as a risk factor for HZ by inhibiting cell-mediated immunity, and patients with low ALC at the time of bortezomib treatment initiation were at greater risk of HZ during bortezomib treatment.
