153 research outputs found
A scalable two-stage Bayesian approach accounting for exposure measurement error in environmental epidemiology
Accounting for exposure measurement errors has been recognized as a crucial
problem in environmental epidemiology for over two decades. Bayesian
hierarchical models offer a coherent probabilistic framework for evaluating
associations between environmental exposures and health effects, which take
into account exposure measurement errors introduced by uncertainty in the
estimated exposure as well as spatial misalignment between the exposure and
health outcome data. While two-stage Bayesian analyses are often regarded as a
good alternative to fully Bayesian analyses when joint estimation is not
feasible, there has been minimal research on how to properly propagate
uncertainty from the first-stage exposure model to the second-stage health
model, especially in the case of a large number of participant locations along
with spatially correlated exposures. We propose a scalable two-stage Bayesian
approach, called a sparse multivariate normal (sparse MVN) prior approach,
based on the Vecchia approximation for assessing associations between exposure
and health outcomes in environmental epidemiology. We compare its performance
with existing approaches through simulation. Our sparse MVN prior approach
shows comparable performance with the fully Bayesian approach, which is a gold
standard but is impossible to implement in some cases. We investigate the
association between source-specific exposures and pollutant (nitrogen dioxide
(NO))-specific exposures and birth outcomes for 2012 in Harris County,
Texas, using several approaches, including the newly developed method.Comment: 34 pages, 8 figure
‘It’s better than daytime television’: questioning the socio-spatial impacts of massage parlours on residential communities
It has been shown that street sex work is problematic for some communities, but there is less evidence of the effects of brothels. Emerging research also suggests that impact discourses outlined by residential communities and in regulatory policies should be critiqued, because they are often based on minority community voices, and limited tangible evidence is used to masquerade wider moral viewpoints about the place of sex work. Using a study of residents living in close proximity to brothels in Blackpool, this paper argues that impact is socially and spatially fluid. Impact needs to be evaluated in a more nuanced manner, which is considerate of the heterogeneity of (even one type of) sex work, and the community in question. Brothels in Blackpool had a variety of roles in the everyday socio-spatial fabric; thus also questioning the common assumption that sex work only impacts negatively on residential communities
Identifying Sensitive Windows of Exposure to NO2 and Fetal Growth Trajectories in a Spanish Birth Cohort
Background: We previously identified associations between trimester-specific NO2 exposures and reduced fetal growth in the Spanish INfancia y Medio Ambiente (INMA) project. Here, we use temporally refined exposure estimates to explore the impact of narrow (weekly) windows of exposure on fetal growth. Methods: We included 1,685 women from INMA with serial ultrasounds at 12, 20, and 34 gestational weeks. We measured biparietal diameter (BPD), femur length, and abdominal circumference (AC) and from them calculated estimated fetal weight (EFW). We calculated z-scores describing trajectories of each parameter during early (0-12 weeks), mid (12-20 weeks), and late (20-34 weeks) pregnancy, based on longitudinal growth curves from mixed-effects models. We estimated weekly NO2 exposures at each woman's residence using land-use regression models. We applied distributed lag nonlinear models to identify sensitive windows of exposure. We present effect estimates as the percentage change in fetal growth per 10 mu g/m(3) increase in NO2 exposure, and we calculated cumulative effect estimates by aggregating estimates across adjacent lags. Results: We identified weeks 5-12 as a sensitive window for NO2 exposure on late EFW (cumulative beta = -3.0%; 95% CI = -4.1%, -1.9%). We identified weeks 6-19 as a sensitive window for late growth in BPD (cumulative beta = -2.0%; 95% CI = -2.7%, -1.4%) and weeks 8-13 for AC (cumulative beta = -0.68%; 95% CI = -0.97%, -0.40%). We found suggestive evidence that third trimester NO2 exposure is associated with increased AC, BPD, and EFW growth in late pregnancy. Conclusions: Our findings are consistent with the hypothesis that NO2 exposure is associated with alterations in growth of EFW, BPD, and AC dependent on the specific timing of exposure during gestation.K.W.W. and E.S. were partially supported by the P30 Environmental Health Sciences Core Center grant P30ES030285 from the National Institute
Occupational cancer in Britain: Exposure assessment methodology
To estimate the current occupational cancer burden due to past exposures in Britain, estimates of the number of exposed workers at different levels are required, as well as risk estimates of cancer due to the exposures. This paper describes the methods and results for estimating the historical exposures. All occupational carcinogens or exposure circumstances classified by the International Agency for Research on Cancer as definite or probable human carcinogens and potentially to be found in British workplaces over the past 20–40 years were included in this study. Estimates of the number of people exposed by industrial sector were based predominantly on two sources of data, the CARcinogen EXposure (CAREX) database and the UK Labour Force Survey. Where possible, multiple and overlapping exposures were taken into account. Dose–response risk estimates were generally not available in the epidemiological literature for the cancer–exposure pairs in this study, and none of the sources available for obtaining the numbers exposed provided data by different levels of exposure. Industrial sectors were therefore assigned using expert judgement to ‘higher'- and ‘lower'-exposure groups based on the similarity of exposure to the population in the key epidemiological studies from which risk estimates had been selected. Estimates of historical exposure prevalence were obtained for 41 carcinogens or occupational circumstances. These include exposures to chemicals and metals, combustion products, other mixtures or groups of chemicals, mineral and biological dusts, physical agents and work patterns, as well as occupations and industries that have been associated with increased risk of cancer, but for which the causative agents are unknown. There were more than half a million workers exposed to each of six carcinogens (radon, solar radiation, crystalline silica, mineral oils, non-arsenical insecticides and 2,3,7,8-tetrachlorodibenzo-p-dioxin); other agents to which a large number of workers are exposed included benzene, diesel engine exhaust and environmental tobacco smoke. The study has highlighted several industrial sectors with large proportions of workers potentially exposed to multiple carcinogens. The relevant available data have been used to generate estimates of the prevalence of past exposure to occupational carcinogens to enable the occupational cancer burden in Britain to be estimated. These data are considered adequate for the present purpose, but new data on the prevalence and intensity of current occupational exposure to carcinogens should be collected to ensure that future policy decisions be based on reliable evidence
Susceptible windows of exposure to fine particulate matter and fetal growth trajectories in the Spanish INMA (INfancia y Medio Ambiente) birth cohort
While prior studies report associations between fine particulate matter (PM2.5) exposure and fetal growth, few have explored temporally refined susceptible windows of exposure.We included 2328 women from the Spanish INMA Project from 2003 to 2008. Longitudinal growth curves were constructed for each fetus using ultrasounds from 12, 20, and 34 gestational weeks. Z-scores representing growth trajectories of biparietal diameter, femur length, abdominal circumference (AC), and estimated fetal weight (EFW) during early (0-12 weeks), mid-(12-20 weeks), and late (20-34 weeks) pregnancy were calcu-lated. A spatio-temporal random forest model with back-extrapolation provided weekly PM2.5 exposure estimates for each woman during her pregnancy. Distributed lag non-linear models were implemented within the Bayesian hierarchical framework to identify susceptible windows of exposure for each outcome and cumulative effects [13cum, 95% credible interval (CrI)] were aggregated across adjacent weeks. For comparison, general linear models evaluated associations between PM2.5 averaged across multi-week periods (i.e., weeks 1-11, 12-19, and 20-33) and fetal growth, mutually adjusted for exposure during each period. Results are presented as %change in z-scores per 5 mu g/m3 in PM2.5, adjusted for covariates.Weeks 1-6 [13cum =-0.77%, 95%CrI (-1.07%,-0.47%)] were identified as a susceptible window of exposure for reduced late pregnancy EFW while weeks 29-33 were positively associated with this outcome [13cum = 0.42%, 95%CrI (0.20%, 0.64%)]. A similar pattern was observed for AC in late pregnancy. In linear regression models, PM2.5 exposure averaged across weeks 1-11 was associated with reduced late pregnancy EFW and AC; but, positive associations between PM2.5 and EFW or AC trajectories in late pregnancy were not observed.PM2.5 exposures during specific weeks may affect fetal growth differentially across pregnancy and such as-sociations may be missed by averaging exposure across multi-week periods, highlighting the importance of temporally refined exposure estimates when studying the associations of air pollution with fetal growth
“A Cathartic Moment in a Man’s Life”: Homosociality and Gendered Fun on the Puttan Tour
Rarely addressed in academic scholarship, the puttan tour is a well-known form of entertainment in Italy where young men drive around in small groups with the aim of spotting street sex workers. On some occasions, the participants will approach the sex workers to strike up a conversation. On others, they will shout out insults from their car then drive away. This article aims to advance a detailed analysis of this underexplored cultural practice drawing on a diverse body of scholarship exploring the intersection of masculinity, leisure, and homosociality. By analyzing stories of puttan tours gathered mostly online, including written accounts and YouTube videos, our aim is to explore the appeal of the puttan tour through an analysis of how homosociality, humor, and laughter operate in this example of gendered fun. To this end, we look at the multiple and often equivocal meanings of this homosocial male-bonding ritual, its emotional and affective dynamics, and the ways in which it reproduces structures of inequality while normalizing violence against sex workers
Maternal Occupational Exposure to Polycyclic Aromatic Hydrocarbons: Effects on Gastroschisis among Offspring in the National Birth Defects Prevention Study
Background: Exposure to polycyclic aromatic hydrocarbons (PAHs) occurs in many occupational settings. There is evidence in animal models that maternal exposure to PAHs during pregnancy is associated with gastroschisis in offspring; however, to our knowledge, no human studies examining this association have been conducted
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