Is the radon risk overestimated? Neglected doses in the estimation of the risk of lung cancer in uranium underground miners

Only the exposure to inhaled radon decay products is usually taken into account in the determination of the risk of radiogenic lung cancer in uranium miners. However, the elevated lung cancer risk in uranium miners is due to the total dose of radiation received by that organ, not to the dose from inhaled radon-222 decay products (222Rn D.P.) alone. Lung doses from sources other than 222Rn D.P. may reach 25% to 75% of total effective dose, absorbed dose or equivalent lung dose, are correlated to 222Rn D.P. doses and are quite variable between facilities. Therefore, to neglect these doses leads to a systematic overestimation of the risk of lung cancer per unit 222Rn D.P. exposure, both through dose underestimation and dose misclassification. Correction for neglected doses and dose misclassification would pull the risk per unit radon exposure downward by a factor of at least two or three and bring the overall dose-effect relationship towards the no-effect null hypothesis, thereby increasing the likelihood of thresholds for lung cancer risk at indoor and today's uranium mine exposures.     

Mammographic screening: is the benefit worth the risk?

Justification of medical exposures is a fundamental principle of radiation protection. This principle applies to mammographic screening, both for the screened population and at an individual level. The benefit of mammographic screening may be considered to be the number of cancers detected or lives saved by breast screening. The risk is the hypothetical number of fatal cancers induced by the use of ionising radiation in screening mammography. Benefit can be deduced from the cancer detection rate in the NHS Breast Screening Programme. The number of additional lives saved by the intervention of a screening programme may be deduced from knowledge of the change in tumour size, stage and nodal status (and hence prognosis) in women with screening detected breast cancers compared with symptomatic women before screening. Calculations of benefit risk ratios to the UK population have been performed. It is concluded that breast screening is justified in radiation protection terms.     

Motor ability: protective or risk for school injuries?

The study aims were to assess the independent contribution of motor ability to the incidence of school injuries. The study included 2057 pupils in grades 3-6 of primary schools in a city in the north of Israel. A surveillance system gathered information about injuries that occurred on school premises or during school related activities and required medical treatment or caused limitation of usual activities. Children provided information on sensation seeking, self-appraisal of health, academic performance, physical activity, and dominant hand; anthropometric measurements and motor ability tests were performed.The incidence of injury events was 4% (95% CI=3.2-5.0). Injuries increased with increased balance and agility, but there were no differences according to reaction time. No other study variables were associated with the incidence of injuries. Our findings of an increase in the incidence of injuries with better motor ability may express differences in exposure to risk situations between children with better and poorer motor abilities.     

‘Anticipatory batch insertion’ to mitigate perceived processing risk

Literature on lot-sizing models with random yields has been traditionally limited to random occurrences that cannot be anticipated in advance; for instance, day-to-day production errors and minor machine repairs. However, in reality, manufacturing processes are subject to other risks that are anticipatory, or non-random, in nature. One example would be yield loss resulting from non-random events such as process, product or material changes. Yield uncertainties of these types are temporary in nature with an impact that decays over time until the manufacturing system fully re-stabilises. One way of reducing the impact of such events is to split the lot and to process a small sub-batch in advance to stabilise the process, thus absorbing the risk associated with the change event. We refer to this approach as ‘anticipatory batch insertion’. This paper presents an exploratory study to analyse the performance of batch insertion under various scenarios related to product sensitivity, risk magnitude and schedule hardness. Results indicate that batch insertion is most advantageous whenever the production schedule is loose, multiple products are sensitive to the risk and the risk magnitude is high.     

Critical factors and paths influencing construction workers’ safety risk tolerances

While workers’ safety risk tolerances have been regarded as a main reason for their unsafe behaviors, little is known about why different people have different risk tolerances even when confronting the same situation. The aim of this research is to identify the critical factors and paths that influence workers’ safety risk tolerance and to explore how they contribute to accident causal model from a system thinking perceptive. A number of methods were carried out to analyze the data collected through interviews and questionnaire surveys. In the first and second steps of the research, factor identification, factor ranking and factor analysis were carried out, and the results show that workers’ safety risk tolerance can be influenced by four groups of factors, namely: (1) personal subjective perception; (2) work knowledge and experiences; (3) work characteristics; and (4) safety management. In the third step of the research, hypothetical influencing path model was developed and tested by using structural equation modeling (SEM). It is found that the effects of external factors (safety management and work characteristics) on risk tolerance are larger than that of internal factors (personal subjective perception and work knowledge & experiences). Specifically, safety management contributes the most to workers’ safety risk tolerance through its direct effect and indirect effect; while personal subjective perception comes the second and can act as an intermedia for work characteristics. This research provides an in-depth insight of workers’ unsafe behaviors by depicting the contributing factors as shown in the accident causal model developed in this research.     

Antecedents of proactive supply chain risk management – a contingency theory perspective

Since supplier insolvencies are a major source of supply chain disruptions, scholars have continuously suggested managing supply chain risk management (SCRM) proactively in order to avoid their occurrence. However, business practice seems to fail with this task. This paper investigates antecedents which foster proactive SCRM implementation from a contingency theory perspective. As a major contingency we choose past supplier insolvencies as an indicator for the level of vulnerability of organisations and investigate inter-organisational, intra-organisational, and individual antecedents. By consulting supply chain management and management accounting literature, hypotheses are developed and tested via content analysis in 63 interviews with representatives from the automotive industry. The findings demonstrate that a mechanistic management control system, a rational cognitive style and relational buyer–supplier relationships have positive impacts on proactively managing supplier insolvency risks. Furthermore, past experience with supplier insolvencies has a moderating, though not a direct, effect on proactiveness. This research suggests that a holistic risk management approach is required to proactively mitigate supplier insolvency risk.     

Are drivers aware of sleepiness and increasing crash risk while driving?

Drivers are advised to take breaks when they feel too tired to drive, but there is question over whether they are able to detect increasing fatigue and sleepiness sufficiently to decide when to take a break. The aim of this study was to investigate the extent to which drivers have access to cognitive information about their current state of sleepiness, likelihood of falling asleep, and the implications for driving performance and the likelihood of crashing. Ninety drivers were recruited to do a 2 h drive in a driving simulator. They were divided into three groups: one made ratings of their sleepiness, likelihood of falling asleep and likelihood of crashing over the next few minutes at prompts occurring at 200 s intervals throughout the drive, the second rated sleepiness and likelihood of falling asleep at prompts but pressed a button on the steering wheel at any time if they felt they were near to crashing and the third made no ratings and only used a button-press if they felt a crash was likely. Fatigue and sleepiness was encouraged by monotonous driving conditions, an imposed shorter than usual sleep on the night before and by afternoon testing. Drivers who reported that they were possibly, likely or very likely to fall asleep in the next few minutes, were more than four times more likely to crash subsequently. Those who rated themselves as sleepy or likely to fall asleep had a more than 9-fold increase in the hazards of a centerline crossing compared to those who rated themselves as alert. The research shows clearly that drivers can detect changes in their levels of sleepiness sufficiently to make a safe decision to stop driving due to sleepiness. Therefore, road safety policy needs to move from reminding drivers of the signs of sleepiness and focus on encouraging drivers to respond to obvious indicators of fatigue and sleepiness and consequent increased crash risk.     

Does exposure to residential radon increase the risk of lung cancer?

In assessing the risks of exposure to ionising radiation, it is important to neither overstate nor understate the effects of the hazard. These requirements are often difficult to satisfy, especially since much of our knowledge about the effects of low levels of radiation is subject to rather large uncertainties. Our participants have given their opinions about the risk of lung cancer induction resulting from exposure to radon in residences. Each agrees that exposures to high concentrations of radon are hazardous. However, as with low level exposures to other types of ionising radiation, quantifying relatively small risks is quite difficult. The national and international standards setting bodies have recommended a fairly conservative approach that may overestimate the 'true' magnitude of deleterious effects and their dependence upon exposure, but this is to be expected given the uncertainties in the data and the need to avoid underestimates. A conservative approach can have both positive and negative consequences, and it is also important to neither overstate nor understate these consequences.     

Predicting cycling accident risk in Brussels: A spatial case–control approach

This paper aims at predicting cycling accident risk for an entire network and identifying how road infrastructure influences cycling safety in the Brussels-Capital Region (Belgium). A spatial Bayesian modelling approach is proposed using a binary dependent variable (accident, no accident at location i) constructed from a case–control strategy. Control sites are sampled along the ‘bikeable’ road network in function of the potential bicycle traffic transiting in each ward. Risk factors are limited to infrastructure, traffic and environmental characteristics.     

Does gender moderate the relationship between driver aggression and its risk factors?

Aim

The current study assessed gender as a potential moderator of the relationship between self-reported driver aggression and various demographic variables, general and driving-related risk factors.

Methods

Using data from a general-population telephone survey conducted from July 2002 through June 2005, two approaches to binary logistic regression were adopted. Based on the full dataset (n = 6259), the initial analysis was a hierarchical-entry regression examining self-reported driver aggression in the last 12 months. All demographic variables (i.e., gender, age, income, education, marital status), general risk factors (i.e., psychological distress, binge drinking, cannabis use), and driving-related risk factors (i.e., driving exposure, stressful driving, exposure to busy roads, driving after drinking, driving after cannabis use) were entered in the first block, and all two-way interactions with gender were entered stepwise in the second block. The subsequent analysis involved dividing the sample by gender and conducting logistic regressions with main effects only for males (n = 2921) and females (n = 3338) separately.

Results

Although the prevalence of driver aggression in the current sample was slightly higher among males (38.5%) than females (32.9%), the difference was small, and gender did not enter as a significant predictor of driver aggression in the overall logistic regression. In that analysis, difficulty with social functioning and being older were associated with a reduced risk of driver aggression. Marital status and education were unrelated to aggression, and all other variables were associated with an increased risk of aggression. Gender was found to moderate the relationships between driver aggression and only three variables: income, psychological distress, and driving exposure. Separate analyses on the male and female sub-samples also found differences in the predictive value of income and driving exposure; however, the difference for psychological distress could not be detected using this separate regression approach. The secondary analysis also identified slight differences in the predictive value of four of the risk factors, where the odds ratios for both males and females were in the same direction but only one of the two was statistically significant.

Conclusions

The results demonstrate the importance of conducting the gender analysis using both regression approaches. With few exceptions, factors that were predictive of driver aggression were generally the same for both male and female drivers.     

The accidental risk assessment methodology for industries (ARAMIS)/layer of protection analysis (LOPA) methodology: A step forward towards convergent practices in risk assessment?

In the last ten years, layer of protection analysis (LOPA) emerged as a simplified form of quantitative risk assessment (QRA). The European Commission funded project Accidental Risk Assessment Methodology for Industries in the context of the Seveso 2 Directive (ARAMIS) has recently been completed. ARAMIS has several modules which give a consistent simplified approach to risk assessment which does not approach the complexity or expense of full QRA. LOPA is potentially a means of carrying out the assessment of barriers required in ARAMIS. This paper attempts to explain the principles of LOPA and the means by which it can be used within ARAMIS.     

Do age-based mandatory assessments reduce older drivers’ risk to other road users?

To assess whether different licensing policies were associated with different fatality levels, the fatality outcomes of older drivers in Victoria and New South Wales (NSW) were compared. In Victoria, there is no age-based assessment required for re-licensing, while in NSW, drivers aged 80 years and older are required to provide annual medical certificates and from age 85, are required to pass on-road driving tests. Fatality rates associated with older drivers in each jurisdiction were calculated for the main categories of road users on two bases: per number of target drivers and per number of licensed drivers. When fatality outcomes were considered relative to the number of 80-plus year-olds in the Victorian and NSW populations, there was no significant difference in the overall fatality rate between the two groups. Similarly, there was no significant difference between the two groups in terms of the fatality rate for all other road users and for road users not in the older drivers’ vehicles. When fatality outcomes were considered relative to the number of 80-plus year-old licensed drivers in either Victoria or NSW, Victorian older drivers were associated with a lower overall fatality rate and the difference was marginally statistically significant. Victorian older drivers were also associated significantly lower fatality rate for road users not in the older drivers’ vehicles. Victorian older drivers represented a statistically significant higher risk in one major regard: to their passengers. Victorian drivers aged 80 years and older had between two and three times higher passenger fatality rates compared to NSW drivers. However it was also found that Victorian older drivers had a significantly higher passenger occupancy rate than their NSW equivalents. Once Victorian and NSW older drivers’ different passenger occupancy rates were controlled for, there were no statistically significant differences across the two jurisdictions. These findings collectively suggested that age-based mandatory assessment programs do not have demonstrable safety benefits, in terms of either total fatalities or other road user fatalities—thereby broadly confirming the findings from previous research based on older driver crash involvement.     

Panel discussion: Do non-targeted effects impact the relation between microdosimetry and risk?

An invited panel discussed with the participants of the Symposium their views on the impact of non-targeted effects on the relationship between microdosimetry and risk. The discussion was wide ranging and lively, with divergences of opinion. At one end was the view that understanding microscopic features and distributions of radiation was an essential component to understanding risk, especially at low doses, and additionally that substantial questions and uncertainties arose from lack of information on the mechanisms and consequences of non-targeted effects. At the other end, it was held that microdosimetry and non-targeted effects are irrelevant to practical radiation protection because protection practice is already securely founded on macroscopic organ doses and direct epidemiological observations of risk. A summary of the discussion is provided in the sequence in which it took place. The session illustrated the underlying mixture of fundamental and practical issues and the need for increased scientific knowledge.     

Severe bicycling injury risk factors in children and adolescents: A case–control study

Background

Bicycling is the most common cause of sports and recreation injury in children and adolescents; yet, there is limited evidence on the factors associated with severe bicycling injuries in youth.

Methods

Case–control study of injured bicyclists less than 18 years old seen in seven emergency departments (EDs) from May 2008 to October 2010. Cases were bicyclists hospitalized after their ED visit (severe injury). Controls were bicyclists seen and discharged from the ED (non-severe injury). Personal, environmental, and crash characteristics were collected by interview. Injury data were collected from medical charts. Crude and adjusted odds ratios (ORs) and 95% confidence intervals (CIs) from logistic regression were used to estimate the odds of hospitalization associated with risk factors. Multiple imputation techniques were employed to address missing data.

Results

There were 1470 participants including 119 cases. Those ages 13–17 had the highest proportion (23%) of severe injuries resulting from motor vehicle [MV] collision. In models including age, sex and MV collision, being male (OR: 2.02; 95% CI: 1.21–3.38), not wearing a helmet (OR: 2.18; 95% CI: 1.43–3.31) and MV collision (OR: 3.91; 95% CI: 2.26–6.78) were significant risk factors for severe injury. Riding on a paved surface (OR: 0.63; 95% CI: 0.41–0.97) and utilitarian (school, work) bicycling (OR: 0.44; 95% CI: 0.2–0.94) decreased injury risk. Results were similar, apart from utilitarian bicycling (OR: 0.49; 95% CI: 0.22–1.06), after imputation for missing data.

Conclusion

Bicycle–MV collisions increase severe injury risk in youth, and adolescents are often injured in these events. This suggests separating bicyclists from MVs or traffic calming strategies could improve safety.     

A fuzzy multi-criteria decision-making approach for managing performance and risk in integrated procurement–production planning

Nowadays in Supply Chain (SC) networks, a high level of risk comes from SC partners. An effective risk management process becomes as a consequence mandatory, especially at the tactical planning level. The aim of this article is to present a risk-oriented integrated procurement–production approach for tactical planning in a multi-echelon SC network involving multiple suppliers, multiple parallel manufacturing plants, multiple subcontractors and several customers. An originality of the work is to combine an analytical model allowing to build feasible scenarios and a multi-criteria approach for assessing these scenarios. The literature has mainly addressed the problem through cost or profit-based optimisation and seldom considers more qualitative yet important criteria linked to risk, like trust in the supplier, flexibility or resilience. Unlike the traditional approaches, we present a method evaluating each possible supply scenario through performance-based and risk-based decision criteria, involving both qualitative and quantitative factors, in order to clearly separate the performance of a scenario and the risk taken if it is adopted. Since the decision-maker often cannot provide crisp values for some critical data, fuzzy sets theory is suggested in order to model vague information based on subjective expertise. Fuzzy Technique for Order of Preference by Similarity to Ideal Solution is used to determine both the performance and risk measures correlated to each possible tactical plan. The applicability and tractability of the proposed approach is shown on an illustrative example and a sensitivity analysis is performed to investigate the influence of criteria weights on the selection of the procurement–production plan.     

Overweight children: Are they at increased risk for severe injury in motor vehicle collisions?

Background

Obesity is an epidemic in the United States. The relationship between traumatic injury and obesity in children is not well-studied. We hypothesized that overweight children suffer more severe injuries, different distributions of injuries and improper use of restraints in motor vehicle collisions.

Methods

We conducted a secondary analysis of the CIREN database of motor vehicle collisions of subjects 2-17 years old. Overweight was defined as a BMI percentile for age >85%. Significant injury was an Injury Severity Score (ISS) >15 or an Abbreviated Injury Scale (AIS) score greater than one. Further analysis looked at injuries classified as head, trunk, or extremities and appropriateness of restraints. Odds ratios compared the overweight to lean groups.

Results

335 subjects met inclusion criteria with 35.5% of cases being overweight. For significant injury, overweight cases had an odds ratio of 1.2 [95% CI: 0.8-1.9]. Analysis by AIS for overall significant injury and to specific body regions also did not show any significant associations. Overweight versus lean subjects had an odds ratio of 1.3 [95% CI: 0.8-2.1] for improper use of restraints.

Conclusions

We found no significant relationship between pediatric injury severity, distribution of injuries, or restraint use and being overweight. Limitations of this study were the small sample size in this database and the large number of unrestrained subjects.     

Multilevel models for evaluating the risk of pedestrian–motor vehicle collisions at intersections and mid-blocks

Walking is a popular form of physical activity associated with clear health benefits. Promoting safe walking for pedestrians requires evaluating the risk of pedestrian–motor vehicle collisions at specific roadway locations in order to identify where road improvements and other interventions may be needed. The objective of this analysis was to estimate the risk of pedestrian collisions at intersections and mid-blocks in Seattle, WA. The study used 2007–2013 pedestrian–motor vehicle collision data from police reports and detailed characteristics of the microenvironment and macroenvironment at intersection and mid-block locations. The primary outcome was the number of pedestrian–motor vehicle collisions over time at each location (incident rate ratio [IRR] and 95% confidence interval [95% CI]). Multilevel mixed effects Poisson models accounted for correlation within and between locations and census blocks over time. Analysis accounted for pedestrian and vehicle activity (e.g., residential density and road classification). In the final multivariable model, intersections with 4 segments or 5 or more segments had higher pedestrian collision rates compared to mid-blocks. Non-residential roads had significantly higher rates than residential roads, with principal arterials having the highest collision rate. The pedestrian collision rate was higher by 9% per 10 feet of street width. Locations with traffic signals had twice the collision rate of locations without a signal and those with marked crosswalks also had a higher rate. Locations with a marked crosswalk also had higher risk of collision. Locations with a one-way road or those with signs encouraging motorists to cede the right-of-way to pedestrians had fewer pedestrian collisions. Collision rates were higher in locations that encourage greater pedestrian activity (more bus use, more fast food restaurants, higher employment, residential, and population densities). Locations with higher intersection density had a lower rate of collisions as did those in areas with higher residential property values. The novel spatiotemporal approach used that integrates road/crossing characteristics with surrounding neighborhood characteristics should help city agencies better identify high-risk locations for further study and analysis. Improving roads and making them safer for pedestrians achieves the public health goals of reducing pedestrian collisions and promoting physical activity.