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2017
2017
2017
2017
BACKGROUND
Ambient air pollution and tuberculosis (TB) have an impact on public health worldwide, yet associations between the two remain uncertain.
OBJECTIVE
We determined the impact of residential traffic on mortality during treatment of active TB.
METHODS
From 2000-2012, we enrolled 32,875 patients in California with active TB and followed them throughout treatment. We obtained patient data from the California Tuberculosis Registry and calculated traffic volumes and traffic densities in 100- to 400-m radius buffers around residential addresses. We used Cox models to determine mortality hazard ratios, controlling for demographic, socioeconomic, and clinical potential confounders. We categorized traffic exposures as quintiles and determined trends using Wald tests.
RESULTS
Participants contributed 22,576 person-years at risk. There were 2,305 deaths during treatment for a crude mortality rate of 1,021 deaths per 10,000 person-years. Traffic volumes and traffic densities in all buffers around patient residences were associated with increased mortality during TB treatment, although the findings were not statistically significant in all buffers. As the buffer size decreased, fifth-quintile mortality hazards increased, and trends across quintiles of traffic exposure became more statistically significant. Increasing quintiles of nearest-road traffic volumes in the 100-m buffer were associated with 3%, 14%, 19%, and 28% increased risk of death during TB treatment [first quintile, referent; second quintile hazard ratio (HR)=1.03 [95% confidence interval (CI): 0.86, 1.25]; third quintile HR=1.14 (95% CI: 0.95, 1.37); fourth quintile HR=1.19 (95% CI: 0.99, 1.43); fifth quintile HR=1.28 (95% CI: 1.07, 1.53), respectively; p-trend=0.002].
CONCLUSIONS
Residential proximity to road traffic volumes and traffic density were associated with increased all-cause mortality in patients undergoing treatment for active tuberculosis even after adjusting for multiple demographic, socioeconomic, and clinical factors, suggesting that TB patients are susceptible to the adverse health effects of traffic-related air pollution. https://doi.org/10.1289/EHP1699.
View on PubMed2017
2017
2017
OBJECTIVE
Hepatic steatosis is common in HIV-infected individuals. Magnetic resonance spectroscopy (MRS) is the preferred noninvasive method for hepatic steatosis measurement but is expensive. Controlled attenuation parameter (CAP) also assesses hepatic steatosis and is conveniently performed concomitantly with transient elastography. We aimed to assess the accuracy of CAP in the setting of HIV infection.
DESIGN
Cross-sectional study.
METHODS
CAP and MRS were performed in 82 study participants (39 HIV monoinfected; seven hepatitis C virus (HCV) monoinfected; 21 HIV/HCV coinfected; 15 with neither infection). We used concordance correlation coefficients to compare log-transformed and standardized CAP and MRS values and linear regression to examine factors associated with CAP and MRS-measured hepatic steatosis (MRS-HS). The accuracy of CAP to detect at least mild hepatic steatosis, defined as MRS-liver fat fraction more than 0.05, and the factors associated with discordance between CAP and MRS were evaluated.
RESULTS
Overall, CAP-measured hepatic steatosis and MRS-HS correlated moderately well (rc = 0.63; P < 0.001), and correlation was strongest in the HIV-monoinfected group (rc = 0.67; P < 0.001). Body composition factors (higher BMI, waist circumference, visceral and abdominal subcutaneous adipose tissue) and insulin resistance were significantly associated with both greater CAP-measured hepatic steatosis and MRS-HS. Using a validated CAP cut-off of at least 238 dB/m, sensitivity and specificity for at least mild hepatic steatosis were 84% and 75% in the entire cohort; 89% and 80% in the HIV-monoinfected group. Participants with higher body composition parameters were more likely to be misclassified as having hepatic steatosis by CAP.
CONCLUSION
Our findings suggest CAP is an acceptable noninvasive surrogate for hepatic steatosis in HIV-infected individuals but may overestimate hepatic steatosis prevalence, especially in individuals with high BMI. Evaluation of factors that improve CAP accuracy and determination of optimal cut-offs are warranted.
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