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1.
J Environ Manage ; 366: 121659, 2024 Jul 10.
Article in English | MEDLINE | ID: mdl-38991344

ABSTRACT

Mountain forests play an essential role in protecting people and infrastructure from natural hazards. However, forests are currently experiencing an increasing rate of natural disturbances (including windthrows, bark beetle outbreaks and forest fires) that may jeopardize their capacity to provide this ecosystem service in the future. Here, we mapped the risk to forests' protective service across the European Alps by integrating the risk components of hazard (in this case, the probability of a disturbance occurring), exposure (the proportion of forests that protect people or infrastructure), and vulnerability (the probability that the forests lose their protective structure after a disturbance). We combined satellite-based data on forest disturbances from 1986 to 2020 with data on key forest structural characteristics (cover and height) from spaceborne lidar (GEDI), and used ensemble models to predict disturbance probabilities and post-disturbance forest structure based on topographic and climatic predictors. Wind and bark beetles are dominant natural disturbance agents in the Alps, with a mean annual probability of occurrence of 0.05%, while forest fires were less likely (mean annual probability <0.01%), except in the south-western Alps. After a disturbance, over 40% of forests maintained their protective structure, highlighting the important role of residual living or dead trees. Within 30 years after wind and bark beetle disturbance, 61% of forests were likely to either maintain or recover their protective structure. Vulnerability to fires was higher, with 51% of forest still lacking sufficient protective structure 30 years after fire. Fire vulnerability was especially pronounced at dry sites, which also had a high fire hazard. Combining hazard and vulnerability with the exposure of protective forests we identified 186 Alpine municipalities with a high risk to protective forests due to wind and bark beetles, and 117 with a high fire risk. Mapping the disturbance risk to ecosystem services can help identify priority areas for increasing preparedness and managing forests towards lower susceptibility under an intensifying disturbance regime.

2.
Article in English | MEDLINE | ID: mdl-38991975

ABSTRACT

ISSUE ADDRESSED: This article presents a framework to identify hidden psychosocial hazards and emerging mental health risks in the workplace, thereby assisting Persons Conducting a Business or Undertaking. The framework adds value to the processes outlined in SafeWork NSW's Code of Practice for Managing Psychosocial Hazards At Work. Specifically, the article documents a framework to analyse microcultures and back stage sites of enactment where psychosocial hazards and risks may be hidden or obscured in workplace settings. BACKGROUND: The article's framework aims to bring to the surface both the intra and interpersonal tensions employees experience in the social reality they inhabit while they perform their work, thereby positively contributing to organisations and PCBUs by helping them create healthy workplace cultures and psychological safety. METHODS: Specifically, the article discusses partnering with an organisational ethnographer when a PCBU embarks upon psychosocial investigations to: gain access, select employee participants, start conversations, establish rapport, build trust, collect and analyse data. CONCLUSION: This article theoretically contributes to health promotion literatures by offering organisations a complementary way of extracting deeper insights and understandings of psychosocial hazards and emerging mental health risks which are not apparent with traditional methods of inquiry.

3.
Jamba ; 16(1): 1611, 2024.
Article in English | MEDLINE | ID: mdl-38962166

ABSTRACT

The main reason cited for the low participation rate in indexed insurance in Africa is the lack of farmers' involvement in the initial conception. The main aim of this article was, therefore, to design an improved participatory methodology that would help farmers in South Africa gather information on the value they place in new crop insurance initiatives based on weather indices. The main objective of this study was to determine their willingness to pay (WTP) crop insurance in the Eastern Cape. The study adopted a cross-sectional design, and the respondents were selected by using a probability sampling procedure. A sample of 150 respondents was selected. The results from descriptive statistics showed that 62% of the smallholder irrigation scheme farmers were between 52 and above years of age, male and female: 87% and 13%, respectively. The results from the probit model revealed that out of nine variables included in the model, only four namely, logAge square, gender, marital status and age were significantly influencing the WTP index-based crop insurance at 1%, 5% and 10%, respectively. However, age was found to reduce the chances of participating in crop-based insurance. A large proportion of those who were willing to pay insurance had not previously experienced losses because of natural hazards. Therefore, it recommended that the government should use existing extension officers to educate the farmers and promote the importance and benefits of insurance products. Contribution: The results are expected to contribute to the local government to improve disaster resilience through strengthening regional financial funding.

4.
Foodborne Pathog Dis ; 2024 Jul 04.
Article in English | MEDLINE | ID: mdl-38963777

ABSTRACT

Consumers can be exposed to many foodborne biological hazards that cause diseases with varying outcomes and incidence and, therefore, represent different levels of public health burden. To help the French risk managers to rank these hazards and to prioritize food safety actions, we have developed a three-step approach. The first step was to develop a list of foodborne hazards of health concern in mainland France. From an initial list of 335 human pathogenic biological agents, the final list of "retained hazards" consists of 24 hazards, including 12 bacteria (including bacterial toxins and metabolites), 3 viruses and 9 parasites. The second step was to collect data to estimate the disease burden (incidence, Disability Adjusted Life Years) associated with these hazards through food during two time periods: 2008-2013 and 2014-2019. The ranks of the different hazards changed slightly according to the considered period. The third step was the ranking of hazards according to a multicriteria decision support model using the ELECTRE III method. Three ranking criteria were used, where two reflect the severity of the effects (Years of life lost and Years lost due to disability) and one reflects the likelihood (incidence) of the disease. The multicriteria decision analysis approach takes into account the preferences of the risk managers through different sets of weights and the uncertainties associated with the data. The method and the data collected allowed to estimate the health burden of foodborne biological hazards in mainland France and to define a prioritization list for the health authorities.

5.
Am J Epidemiol ; 2024 Jul 05.
Article in English | MEDLINE | ID: mdl-38973755

ABSTRACT

Epidemiologic studies frequently use risk ratios to quantify associations between exposures and binary outcomes. When the data are physically stored at multiple data partners, it can be challenging to perform individual-level analysis if data cannot be pooled centrally due to privacy constraints. Existing methods either require multiple file transfers between each data partner and an analysis center (e.g., distributed regression) or only provide approximate estimation of the risk ratio (e.g., meta-analysis). Here we develop a practical method that requires a single transfer of eight summary-level quantities from each data partner. Our approach leverages an existing risk-set method and software originally developed for Cox regression. Sharing only summary-level information, the proposed method provides risk ratio estimates and confidence intervals identical to those that would be provided - if individual-level data were pooled - by the modified Poisson regression. We justify the method theoretically, confirm its performance using simulated data, and implement it in a distributed analysis of COVID-19 data from the U.S. Food and Drug Administration's Sentinel System.

6.
Arh Hig Rada Toksikol ; 75(2): 110-115, 2024 Jun 01.
Article in English | MEDLINE | ID: mdl-38963140

ABSTRACT

The aim of this study was to explore occupational safety in pregnant Croatian healthcare workers (HCWs) during the coronavirus disease 2019 (COVID-19) pandemic. To this end we composed an anonymous questionnaire that included pregnancy data, risk assessment and mitigation, and workplace intervention and distributed it to HCWs through social media of their groups and associations. The study includes a total of 173 respondents (71.1 % physicians, 19.7 % nurses, 9.2 % other HCWs) diagnosed with pregnancy in 2020 and 2021. Employers were notified about HCWs' pregnancy at the eighth (IQR 7.0-11.0) week of pregnancy, which delayed workplace risk assessment and mitigation beyond the first trimester. Only 19.6 % of the participants had the risk assessed and mitigated, mostly on their own initiative (76.5 %). After notifying employers about pregnancy, 37.0 % of participants opted for temporary work incapacity (TWI) due to "pregnancy complications" despite healthy pregnancy, 16.8 % were granted a pregnant worker's paid leave at the expense of the employer, while 5.8 % continued to work at the same workplace. Nurses used the TWI benefit more frequently than physicians (58.8 % vs 30.1 %, P=0.004). Our findings suggest that occupational safety of pregnant HCWs in Croatia lacks clear-cut and transparent strategies to protect pregnant HCWs, forcing them to misuse the healthcare system.


Subject(s)
COVID-19 , Health Personnel , Occupational Health , Sick Leave , Humans , Female , COVID-19/prevention & control , COVID-19/epidemiology , COVID-19/transmission , Croatia/epidemiology , Pregnancy , Health Personnel/statistics & numerical data , Adult , Occupational Health/statistics & numerical data , Sick Leave/statistics & numerical data , Pandemics/prevention & control , Surveys and Questionnaires , SARS-CoV-2
7.
Eur J Surg Oncol ; 50(9): 108513, 2024 Jun 27.
Article in English | MEDLINE | ID: mdl-38968854

ABSTRACT

INTRODUCTION: Comparative studies on surgical treatments with time-to-event endpoints have provided substantial evidence for clinical practice, but the accurate use of survival data analysis and the control of confounding bias remain big challenges. METHODS: This was a survey of surgical studies with survival outcomes published in four general medical journals and five general surgical journals in 2021. The two most concerned statistical issues were evaluated, including confounding control by propensity score analysis (PSA) or multivariable analysis and testing of proportional hazards (PH) assumption in Cox model. RESULTS: A total of 74 studies were included, comprising 63 observational studies and 11 randomized controlled trials. Among the observational studies, the proportion of studies utilizing PSA in surgical oncology and non-oncology studies was similar (40.9 % versus 36.8 %, P = 0.762). However, the former reported a significantly lower proportion of PH assumption assessments compared to the latter (13.6 % versus 42.1 %, P = 0.020). Twenty-five observational studies (25/63) used PSA methods, but two-thirds of them (17/25) showed unclear balance of baseline data after PSA. And the proportion of PH assumption testing after PSA was slightly lower than that before PSA, but the difference was not statistically significant (24.0 % versus 28.0 %, P = 0.317). Comprehensive suggestions were given on confounding control in survival analysis and alternative resolutions for non-compliance with PH assumption. CONCLUSION: This study highlights suboptimal reporting of PH assumption evaluation in observational surgical studies both before and after PSA. Efforts and consensus are needed with respect to the underlying assumptions of statistical methods.

8.
Article in English | MEDLINE | ID: mdl-38949924

ABSTRACT

Background and Aims: The purpose of this study was to investigate the combined impact of variations in physical activity (PA) and sitting time (ST) on the risk of developing metabolic syndrome (MetS). Methods: This study was conducted on a cohort of adults from the general population, aged 40-69 years, who participated in the KOGES community-based cohort study over a span of 10 years. Changes in PA and ST were assessed using the results from PA questionnaires completed during baseline and follow-up surveys. The diagnosis of MetS was determined according to the criteria established by the International Diabetes Federation. To evaluate the combined effect of PA and ST changes on the incidence of MetS, we calculated hazard ratios and 95% confidence intervals using a Cox proportional hazards regression model. Result: The incidence of MetS was reduced by 39% (HR = 0.61, 95% CI = 0.46-0.82) for increased ST/increased PA and 26% (HR = 0.74, 95% CI = 0.58-0.94) for decreased ST/increased PA, compared with increased ST/decreased PA, respectively. In addition, this study confirmed that the combined impact of changes in PA and ST, based on the domain of PA, on the incidence of MetS varied. Conclusion: Changes in ST and PA are associated with the risk of developing MetS. These findings lay the groundwork for further research on the relationship between changes in PA, ST, and the occurrence of diseases.

9.
Environ Geochem Health ; 46(8): 264, 2024 Jul 01.
Article in English | MEDLINE | ID: mdl-38951364

ABSTRACT

Over the past two decades the Global South is witnessing unprecedented economic transformation and Asian Cities in particular have a remarkable upsurge. Coimbatore, an industrial city in Southern India with an estimated population of 2 million (in 2022) is witnessing a rapid transition in terms of infrastructure development. In this context, the present study attempts to assess the particulate matter (PM10 and PM2.5) emissions at road network construction sites and the heavy metal fractionation in the road dust/sediment samples with a core focus to quantify the bioavailable fraction of metals (Fe, Cu, Cr, Cd, Pb and Ni) and its source apportionment in the road side dust/sediment samples. About 60 composite road dust/sediment samples were collected for heavy metal fractionation analysis in the six arterial roads that undergo core developments like construction of road over bridges, additional road incorporation and street expansions. PM monitoring revealed that 24 h average PM2.5 (47 µg/m3) and PM10 (69 µg/m3) concentrations at many construction sites exceeded 24 h average recommended by WHO guidelines [PM2.5 (15 µg/m3) and PM10 (45 µg/m3), respectively]. The bioavailable fractions of Fe, Cu, Cr and Cd are notably higher in the roadside sediment samples at road construction sites. Health Risk assessment, such as carcinogenic risks (Children-4.41 × 10-2, Adult-3.598 × 10-6) and non-carcinogenic risks, inferred substantial risks at high intensity construction sites with statistical analyses, including PCA and cluster analysis, indicating considerable anthropogenic influences in the heavy metal fractions.


Subject(s)
Dust , Metals, Heavy , Particulate Matter , Metals, Heavy/analysis , India , Dust/analysis , Humans , Particulate Matter/analysis , Air Pollutants/analysis , Risk Assessment , Environmental Monitoring/methods , Cities , Child , Environmental Exposure , Geologic Sediments/chemistry
10.
Acta Cardiol ; : 1-15, 2024 Jul 02.
Article in English | MEDLINE | ID: mdl-38953283

ABSTRACT

BACKGROUND: There hasn't been research done on the connection between serum anion gap (AG) levels and long-, medium-, and short-term all-cause mortality in congestive heart failure (CHF) patients. This study aims to investigate the association between serum anion gap levels and all-cause mortality in CHF patients after adjusting for other covariates. METHODS: For each patient, we gather demographic information, comorbidities, laboratory results, vital signs, and scoring data using the ICU (Intensive Care Unit) Admission Scoring System from the MIMIC-III database. The connection between baseline AG and long-, medium-, and short-term all-cause mortality in critically ill congestive heart failure patients was investigated using Kaplan-Meier survival curves, subgroup analysis, restricted cubic spline, and Cox proportional risk analysis. RESULTS: 4840 patients with congestive heart failure in total were included in this study. With a mean age of 72.5 years, these patients had a gender split of 2567 males and 2273 females. After adjusting for other covariates, a multiple regression analysis revealed that, in critically ill patients with congestive heart failure, all-cause mortality increased significantly with rising AG levels. In the fully adjusted model, we discovered that AG levels were strongly correlated with 4-year, 365-day, 90-day, and 30-day all-cause mortality in congestive heart failure patients with HRs (95% CI) of 1.06 (1.04, 1.08); 1.08 (1.05, 1.10); and 1.08 (1.05, 1.11) (p-value < 0.05). Our subgroup analysis's findings demonstrated a high level of consistency and reliability. K-M survival curves demonstrate that high serum AG levels are associated with a lower survival probability. CONCLUSION: Our research showed the association between CHF patients' all-cause mortality and anion gap levels was non-linear. Elevated anion gap levels are associated with an increased risk of long-, medium-, and short-term all-cause death in patients with congestive heart failure. Continuous monitoring of changes in AG levels may have a clinical predictive role.

11.
Animal ; 18(7): 101214, 2024 Jun 13.
Article in English | MEDLINE | ID: mdl-38970990

ABSTRACT

There is an increasing interest in edible insects in Europe for feed and food purposes. Quantitative information on the transfer of chemical hazards from substrates to larvae is needed to evaluate food and feed safety aspects. This evaluation is especially needed when organic substrates or residual streams such as manure will be applied as substrate, contributing to a circular food system. This study investigated the transfer of veterinary drugs from spiked substrate to black soldier fly larvae (Hermetia illucens). Veterinary drugs that are commonly administered to chicken, fattening pigs, and cattle and regularly detected in manure were included: three different antibiotics (enrofloxacin, oxytetracycline, sulfamethoxazole), three coccidiostats (narasin, salinomycin, toltrazuril) and one antiparasitic drug (eprinomectin). The chemicals were spiked to insect substrate to reach final concentrations of 0.5 and 5 mg/kg for the antibiotics and the antiparasitic drug, and 5 and 50 mg/kg for the coccidiostats. Black soldier fly larvae were reared for 1 week on the spiked substrates, and the transfer of the veterinary drugs to the larvae and frass was quantified using liquid chromatography coupled with tandem mass spectrometry. Only oxytetracycline and eprinomectin reduced the average weight and/or survival of the black soldier fly larvae. The transfer of the veterinary drugs to the larvae was on average 19.2% for oxytetracycline, 12% for enrofloxacin, 9.5% for narasin, 8.1% for eprinomectin, 3.9% for salinomycin, 4.2% for toltrazuril, and 0.2% for sulfamethoxazole, relative to concentrations in the substrate. Mass-balance calculations revealed that the larvae seem to metabolise veterinary drugs, and indeed, metabolites of enrofloxacin, sulfamethoxazole, and toltrazuril were detected in the larvae and frass. In conclusion, insect-rearing substrates should be evaluated for the presence of veterinary drug residues to ensure feed (and food) safety, as well as because of possible effects on insect growth.

12.
Synth Biol (Oxf) ; 9(1): ysae010, 2024.
Article in English | MEDLINE | ID: mdl-38973982

ABSTRACT

Data science is playing an increasingly important role in the design and analysis of engineered biology. This has been fueled by the development of high-throughput methods like massively parallel reporter assays, data-rich microscopy techniques, computational protein structure prediction and design, and the development of whole-cell models able to generate huge volumes of data. Although the ability to apply data-centric analyses in these contexts is appealing and increasingly simple to do, it comes with potential risks. For example, how might biases in the underlying data affect the validity of a result and what might the environmental impact of large-scale data analyses be? Here, we present a community-developed framework for assessing data hazards to help address these concerns and demonstrate its application to two synthetic biology case studies. We show the diversity of considerations that arise in common types of bioengineering projects and provide some guidelines and mitigating steps. Understanding potential issues and dangers when working with data and proactively addressing them will be essential for ensuring the appropriate use of emerging data-intensive AI methods and help increase the trustworthiness of their applications in synthetic biology.

13.
Int J Occup Saf Ergon ; : 1-14, 2024 Jun 30.
Article in English | MEDLINE | ID: mdl-38946205

ABSTRACT

Various toxic and flammable gases exist in the fertilizer industry whose release quantification is very important regarding emergency preparedness, planning and response, and well-being of the community. ALOHA threat zones and threat at a point coupled with MARPLOT are evaluated for ammonia, methane, carbon dioxide and hydrogen release, and outdoor and indoor concentrations of these gases in nearby residences and highways calculated. These footprints are calculated using ALOHA which requires inputs such as site data, site location, building type, gas name, atmospheric inputs, release source information and dispersion model to display the threat zone, which can then be shown on MARPLOT. Potential impact of these releases on the community is mitigated through releasing equipment isolations, water sprays for dilutions, dilutions through steam or air and emergency sirens for information. This article covers hazards in the fertilizer industry, and provides general guidelines for operational staff of any industry to mitigate hazards.

14.
Risk Anal ; 2024 Jul 10.
Article in English | MEDLINE | ID: mdl-38984664

ABSTRACT

We examined hazard and risk-related metrics of the highest- and lowest-income counties and municipalities in each U.S. state. Indicators of natural and anthropogenic hazards, health outcomes, location of locally unwanted land uses, food insecurity, and other metrics were used to measure social and environmental justice. As expected, the highest-income places have better health outcomes, access to assets that protect health, and high municipal ratings of place quality compared with their poorest counterparts. Yet, they also have higher natural hazard risks and are more likely to live near concentrations of anthropogenic hazards. That is, high-income places have a lot to lose. Although the poorest jurisdictions demonstrate cumulative disadvantages, those in rural areas are exposed to less dense motor vehicle traffic and other hazards and risks associated with urban life. Relationships between income and the geography of hazards and risks are not simple. Even the highest-income areas face challenges. We suggest improvements in databases and tools to increase the focus on and monitoring of the breadth of risks people face in all areas.

15.
Heliyon ; 10(12): e32701, 2024 Jun 30.
Article in English | MEDLINE | ID: mdl-38975236

ABSTRACT

Food safety has emerged as a paramount concern for both Vietnamese consumers and the government. However, limited data are available on food safety management systems in Viet Nam. This study identified significant gaps in good agricultural and hygienic practices along the fresh produce chain (farmers and traditional wholesalers/market sellers) in the region of Da Nang, Viet Nam. This was achieved through a survey on good agricultural and hygienic practices for farmers (n = 100) and sellers (n = 100), which researchers further supplemented by microbiological analysis for E. coli, Salmonella spp., and Listeria monocytogenes on leafy greens, water in contact with produce and contact surfaces (hands). The results indicated that 86.0 % of farmers and 54.0 % of sellers received food safety training in the last 3 years; and women dominated both vegetable cultivation but also trading. Farm-level deficiencies included inadequate handwashing practices, lack of documentation for manure application schedules, improper washing and drying of harvest tools, failure to keep containers elevated off the ground, improper storage of vegetables, and inadequate covering of containers, with respectively 34.0 %, 30.3 %, 12.1 %, 41.7 % and 7.9 % of farmers executing the practice as prescribed by the WHO/FAO '5 keys of growing safer fruits and vegetables'. As for sellers, the most dominant gaps (<50.0 % compliance) were the way of handwashing and the practice of keeping containers elevated off the ground before, during, and after harvesting. The microbiological analysis confirmed that, in a total of 36 fresh produce samples including mustard greens, cucumber, lettuce, and crown daisy, the number of samples positive for E. coli, Salmonella spp., and L. monocytogenes were 12, 2, and 10 respectively. Samples of hands and the irrigation water showed high contamination with E. coli. Based on identified gaps, risk communication tools were developed and distributed amongst farmers, sellers, and Da Nang food safety management authority (governmental organisation performing inspections in the traditional food markets). As intervention, two farmers and two sellers were trained in safe agricultural practices for the cultivation of fresh vegetables (managerial intervention) and instructed to use tap water as irrigation water instead of uncontrolled surface water (technological intervention). A post-assessment was conducted, including redoing the survey on good practices and microbiological analysis. The outcome of these interventions showed positive results in terms of good agricultural and hygienic practices resulting in improved hygiene levels and safety of the fresh produce. The findings from this research have the potential to provide a model for the development of a science-based risk management strategy in alternative food chains or geographic areas in emerging countries.

16.
Article in English | MEDLINE | ID: mdl-38978112

ABSTRACT

There is little data on sharps injuries among healthcare workers in West Africa despite the region's high rate of Hepatitis B and HIV. The purpose of this study is to investigate healthcare workers' history of sharps injury in Liberia and Ghana. An electronic cross-sectional survey was administered to healthcare workers in Liberia and Ghana from February to June 2022. A link to the survey was texted to participants through professional association membership lists, including nursing, midwifery, and physician assistant organizations in both Liberia and Ghana and a physician organization in Ghana only. 509 participants reported an average of 1.8 injuries per year in Liberia and 1.1 in Ghana (p=<0.01). 15.1% of healthcare workers reported three or more injuries in the past year. Liberia had a higher proportion of frequently injured workers (p = 0.01). Frequently injured workers were evenly distributed across worker types. Workers in this region are vulnerable to sharps injuries. A frequently injured subset of workers likely has distinctive risk factors and would benefit from further investigation and intervention.

17.
Sci Total Environ ; 946: 174359, 2024 Jun 30.
Article in English | MEDLINE | ID: mdl-38955268

ABSTRACT

Mountain protection forests can prevent natural hazards by reducing their onset and propagation probabilities. In fact, individual trees act as natural barriers against hydrogeomorphic events. However, assessing the structural strength of trees against these hazards is challenging, especially in a context of climate change due to the intensification of extreme events and changes in forest dynamics. Here, we focus on the mechanical analyses of two of the most common tree species across the Pyrenees (Abies alba Mill. and Fagus sylvatica L.) growing in two different areas (Spain and France), and affected by recurrent snow avalanche and rockfall events. We first performed 53 pulling test on mature trees, where the root-plate stiffness and the modulus of elasticity of the stems were evaluated. To further analyse the impact of forest management and climate on protective forests, we yielded information on tree growth using dendroecology techniques. Then, we assessed structure and neighbourhood characteristics for each target tree to account for the surrounding forest structure. Finally, using linear and structured equation models we tested if the mechanical capacity of the trees is determined either by functional traits (e.g. species, tree growth, diameter and height) or forest structural traits (e.g. tree density, tree structure and slenderness) or both. Our results suggest that the forest neighbourhood influences tree mechanical capacity through two pathways, including both functional and structural traits. The individual stiffness parameter of trees is influenced by their functional traits, while their structural traits are more closely related with changes in the modulus of elasticity. Both species exhibit varying levels of dominance in different locations, which is related to their resilience to the diverse natural hazards they confront. Our findings provide relevant insights to anticipating management strategies for forests that serve as a protective barrier against natural hazards in the context of a changing climate.

18.
Biometrics ; 80(3)2024 Jul 01.
Article in English | MEDLINE | ID: mdl-38994640

ABSTRACT

We estimate relative hazards and absolute risks (or cumulative incidence or crude risk) under cause-specific proportional hazards models for competing risks from double nested case-control (DNCC) data. In the DNCC design, controls are time-matched not only to cases from the cause of primary interest, but also to cases from competing risks (the phase-two sample). Complete covariate data are available in the phase-two sample, but other cohort members only have information on survival outcomes and some covariates. Design-weighted estimators use inverse sampling probabilities computed from Samuelsen-type calculations for DNCC. To take advantage of additional information available on all cohort members, we augment the estimating equations with a term that is unbiased for zero but improves the efficiency of estimates from the cause-specific proportional hazards model. We establish the asymptotic properties of the proposed estimators, including the estimator of absolute risk, and derive consistent variance estimators. We show that augmented design-weighted estimators are more efficient than design-weighted estimators. Through simulations, we show that the proposed asymptotic methods yield nominal operating characteristics in practical sample sizes. We illustrate the methods using prostate cancer mortality data from the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial Study of the National Cancer Institute.


Subject(s)
Proportional Hazards Models , Prostatic Neoplasms , Case-Control Studies , Humans , Male , Risk Assessment/statistics & numerical data , Risk Assessment/methods , Prostatic Neoplasms/mortality , Computer Simulation , Data Interpretation, Statistical , Biometry/methods , Risk Factors
19.
J Appl Stat ; 51(9): 1689-1708, 2024.
Article in English | MEDLINE | ID: mdl-38957179

ABSTRACT

In competing risks data, in practice, there may be lack of information or uncertainty about the true failure type, termed as 'missing failure type', for some subjects. We consider a general pattern of missing failure type in which we observe, if not the true failure type, a set of possible failure types containing the true one. In this work, we focus on both parametric and non-parametric estimation based on current status data with two competing risks and the above-mentioned missing failure type. Here, the missing probabilities are assumed to be time-dependent, that is, dependent on both failure and monitoring time points, in addition to being dependent on the true failure type. This makes the missing mechanism non-ignorable. We carry out maximum likelihood estimation and obtain the asymptotic properties of the estimators. Simulation studies are conducted to investigate the finite sample properties of the estimators. Finally, the methods are illustrated through a data set on hearing loss.

20.
Commun Earth Environ ; 5(1): 367, 2024.
Article in English | MEDLINE | ID: mdl-38993331

ABSTRACT

Volcanic lightning detection has proven useful to volcano monitoring by providing information on eruption onset, source parameters, and ash cloud directions. However, little is known about the influence of changing eruptive styles on the generation of charge and electrical discharges inside the eruption column. The 2021 Tajogaite eruption (La Palma, Canary Islands) provided the rare opportunity to monitor variations in electrical activity continuously over several weeks using an electrostatic lightning detector. Here we show that throughout the eruption, silicate particle charging is the main electrification mechanism. Moreover, we find that the type of electrical activity is closely linked to the explosive eruption style. Fluctuations in the electrical discharge rates are likely controlled by variations in the mass eruption rate and/or changes in the eruption style. These findings hold promise for obtaining near real-time information on the dynamic evolution of explosive volcanic activity through electrostatic monitoring in the future.

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