Dataset Information

The Use of Carbonaceous Particle Exposure Metrics in Health Impact Calculations.

ABSTRACT: Combustion-related carbonaceous particles seem to be a better indicator of adverse health effects compared to PM2.5 and PM10. Historical studies are based on black smoke (BS), but more recent studies use absorbance (Abs), black carbon (BC) or elemental carbon (EC) as exposure indicators. To estimate health risks based on BS, we review the literature regarding the relationship between Abs, BS, BC and EC. We also discuss the uncertainties associated with the comparison of relative risks (RRs) based on these conversions. EC is reported to represent a proportion between 5.2% and 27% of BS with a mean value of 12%. Correlations of different metrics at one particular site are higher than when different sites are compared. Comparing all traffic, urban and rural sites, there is no systematic site dependence, indicating that other properties of the particles or errors affect the measurements and obscure the results. It is shown that the estimated daily mortality associated with short-term levels of EC is in the same range as PM10, but this is highly dependent on the EC to BS relationship that is used. RRs for all-cause mortality associated with short-term exposure to PM10 seem to be higher at sites with higher EC concentrations, but more data are needed to verify this.

SUBMITTER: Olstrup H

PROVIDER: S-EPMC4808912 | biostudies-literature | 2016 Feb

REPOSITORIES: biostudies-literature

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The Use of Carbonaceous Particle Exposure Metrics in Health Impact Calculations.

Olstrup Henrik H Johansson Christer C Forsberg Bertil B

International journal of environmental research and public health 20160224 3

Combustion-related carbonaceous particles seem to be a better indicator of adverse health effects compared to PM2.5 and PM10. Historical studies are based on black smoke (BS), but more recent studies use absorbance (Abs), black carbon (BC) or elemental carbon (EC) as exposure indicators. To estimate health risks based on BS, we review the literature regarding the relationship between Abs, BS, BC and EC. We also discuss the uncertainties associated with the comparison of relative risks (RRs) base ...[more]

PMID: 26927139

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Project description:Exposure-response (ER) analyses are routinely performed as part of model-informed drug development to evaluate the risk-to-benefit ratio for dose selection, justification, and confirmation. For logistic regression analyses with binary endpoints, several exposure metrics are investigated, based on pharmacological plausibility, including time-averaged concentration to event (CavTE). CavTE is informative because it accounts for dose interruptions, modifications, and reductions and is therefore often compared against ER relationships identified using steady-state exposures. However, its derivation requires consideration in a logistic regression framework for time-invariant ER analysis because it has the potential to introduce bias. This study evaluated different approaches to derive CavTE for subjects whom did not have an event by the end of treatment (EoT) and assessed their impact on the ER relationship. Here we used a modified model based on a real data example for simulating exposures and events (safety) in different virtual population sizes (n = 50, 100, or 200) and drug effect magnitudes (0.5, 0.75, or 1). Events were generated using a proportional odds model with Markov components. For subjects whom did not experience an event, CavTE was derived at EoT, EoT+7 days, +14 days, +21 days, +28 days. The derivation of CavTE at different time points demonstrated significant impact on trends detected in logistic ER relationships that could bias subsequent event projection, dose selection and Go/No-Go decisions. CavTE in censored subjects must therefore be carefully derived to avoid potentially making false positive or negative conclusions. Overall, CavTE can be a useful exposure metrics in an ER analysis, when considered along with physiological or biological plausibility, the drug's pharmacokinetic, and mechanism of action. Biological plausibility and different analysis factors (e.g., the time of the events with respect to observational period, the level of dose reduction/interruption) should be considered in the choice of the exposure metric. It is recognized that although time-invariant logistic regression is relatively fast and efficient, it overlooks recurring events and does not take into account the exposure and response time course with the potential drawback of ignoring important elements of the analysis like onset or duration of the effect. Care should be taken when ER relationships with other exposure metrics do not identify any statistically significant trends.

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Project description:ImportancePublishing in health professions education (HPE) journals is an integral component of academic discourse and career progression. Research in this field is shifting to an open access (OA) publishing model.ObjectiveTo identify the characteristics and publishing models of HPE journals and explore potential associations between publication costs and journal metrics.Design, setting, and participantsThis cross-sectional study was conducted between September 20, 2023, and February 14, 2024, using the World Bank purchasing power parity (PPP) index to analyze relative costs of article processing charges (APCs). Data on journal characteristics, impact metrics, APCs, and waiver or discount were extracted from the National Library of Medicine, Scimago, Scopus, journal websites, and email correspondence with editorial staff of journals. All HPE journals indexed in PubMed, written in or translated into English, and with HPE as a core component of their mission were included in the analysis.Main outcomes and measuresTwo-year impact factor, H-index, cite score, Scientific Journal Ranking, and APC.ResultsAmong the 51 journals included, 27 (53%) adopted OA-only and 24 (47%) adopted hybrid publishing models. The median (IQR) APC for all journals was $2820.00 ($928.00-$3300.00). Associations were observed between impact factor and APC (β coefficient, $386.84; 95% CI, $226.84-$546.84; P < .001) and between cite score and APC (β coefficient, $282.40; 95% CI, $148.12-$416.61; P < .001). Of 20 journal websites with information regarding fee waivers or discounts, 7 journals (35%) confirmed fee waiver or discount. The PPP index analysis of the top 39 countries publishing HPE research showed that the financial burden of meeting the median APC for publication was 1.94 to 10.26 times higher for authors from lower-income countries than for authors from the US.Conclusions and relevanceResults of this cross-sectional study suggest that adoption by HPE journals of an OA publishing model was high but access to APC waivers or discounts was limited. These factors create barriers to equitable OA practices, necessitating concerted efforts, such as increasing transparency of publishing costs, implementing economic impact analysis, expanding waivers to eligible authors, and applying holistic impact factor scoring.

Dataset Information

The Use of Carbonaceous Particle Exposure Metrics in Health Impact Calculations.

Publications

The Use of Carbonaceous Particle Exposure Metrics in Health Impact Calculations.

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