Adjusting for time-varying confounding in the subdistribution analysis of a competing risk

Despite decades of research in the medical literature, assessment of the attributable mortality due to nosocomial infections in the intensive care unit (ICU) remains controversial, with different studies describing effect estimates ranging from being neutral to extremely risk increasing. Interpretation of study results is further hindered by inappropriate adjustment (a) for censoring of the survival time by discharge from the ICU, and (b) for time-dependent confounders on the causal path from infection to mortality. In previous work (Vansteelandt et al. Biostatistics 10:46–59), we have accommodated this through inverse probability of treatment and censoring weighting. Because censoring due to discharge from the ICU is so intimately connected with a patient’s health condition, the ensuing inverse weighting analyses suffer from influential weights and rely heavily on the assumption that one has measured all common risk factors of ICU discharge and mortality. In this paper, we consider ICU discharge as a competing risk in the sense that we aim to infer the risk of ‘ICU mortality’ over time that would be observed if nosocomial infections could be prevented for the entire study population. For this purpose we develop marginal structural subdistribution hazard models with accompanying estimation methods. In contrast to subdistribution hazard models with time-varying covariates, the proposed approach (a) can accommodate high-dimensional confounders, (b) avoids regression adjustment for post-infection measurements and thereby so-called collider-stratification bias, and (c) results in a well-defined model for the cumulative incidence function. The methods are used to quantify the causal effect of nosocomial pneumonia on ICU mortality using data from the National Surveillance Study of Nosocomial Infections in ICU’s (Belgium).     

In Search of the Sources of Psychologically Controlling Parenting: The Role of Parental Separation Anxiety and Parental Maladaptive Perfectionism

This study investigated the role of two dimensions of parental separation anxiety—Anxiety about Adolescent Distancing (AAD) and Comfort with Secure Base Role (CSBR)—and parental maladaptive perfectionism in the prediction of psychologically controlling parenting. In a sample of middle adolescents and their parents (N=677), it was found that parents' AAD scores and maladaptive perfectionism were positively related to psychological control, whereas parents' CSBR scores were negatively related to psychological control. Further, psychological control served as an intervening variable in the links between parent characteristics and adolescent well‐being. These findings suggest that two qualitatively different types of psychological control may exist: one originating from parents' separation anxiety and another originating from parents' maladaptive perfectionist standards.     

Survey non-response and the duration of unemployment

Summary.  Social surveys are often used to estimate unemployment duration distributions. Survey non-response may then cause a bias. We study this by using a data set that combines survey information of individual workers with administrative records of the same workers. The latter provide information on durations of unemployment and personal characteristics of all survey respondents and non-respondents. We develop a method to distinguish empirically between two explanations for a bias in results based on only survey data: selectivity due to related unobserved determinants of durations of unemployment and non-response and a causal effect of a job exit on non-response. The latter may occur even in fully homogeneous populations. The methodology exploits variation in the timing of the duration outcome relative to the survey moment. The results show evidence for both explanations. We discuss implications for standard methods to deal with non-response bias.     

Radiocarbon peat chronologies and environmental change

Summary.  Raised bog peat deposits form important archives for reconstructing past changes in climate. Precise and reliable age models are of vital importance for interpreting such archives. We propose enhanced, Markov chain Monte Carlo based methods for obtaining age models from radiocarbon-dated peat cores, based on the assumption of piecewise linear accumulation. Included are automatic choice of sections, a measure of the goodness of fit and outlier downweighting. The approach is illustrated by using a peat core from the Netherlands.     

The impact of early-life economic conditionson cause-specific mortality during adulthood

The aim of this study is to assess the effects of economic conditions in early life on cause-specific mortality during adulthood. The analyses are performed on a unique historical sample of 14,520 Dutch individuals born in 1880–1918, who are followed throughout life. The economic conditions in early life are characterized using cyclical variations in annual real per capital gross domestic product during pregnancy and the first year of life. Exposure to recessions in early life appears to significantly increase cancer mortality risks of older males and females. It also significantly increases other mortality risks especially for older females. The residual life expectancies are up to about 8 and 6 % lower for male and female cancer mortality, respectively, and up to about 5 % lower for female cardiovascular mortality. Our analyses show that cardiovascular and cancer mortality risks are related and that not taking this association into account leads to biased inference.     

Investigating Poverty through the Lens of Riches – Immigration and Segregation in Indian Capture Fisheries

This article argues that in the period since 1900 marine capture fisheries are more profitably characterised by a quest for wealth than by enduring poverty. Making use of country data from India, it maintains that the blue revolution that took place in the South not only retained a steadily growing fishing population, but also provided opportunities for large numbers of immigrants, mainly in the lower echelons of the industry. It subsequently investigates the variations between geographical regions and sub‐sectors, and explains them by reference to non‐governmental institutional control patterns.     

Food Safety in the Domestic Environment: The Effect of Consumer Risk Information on Human Disease Risks

The improvement of food safety in the domestic environment requires a transdisciplinary approach, involving interaction between both the social and natural sciences. This approach is applied in a study on risks associated with Campylobacter on broiler meat. First, some web-based information interventions were designed and tested on participant motivation and intentions to cook more safely. Based on these self-reported measures, the intervention supported by the emotion "disgust" was selected as the most promising information intervention. Its effect on microbial cross-contamination was tested by recruiting a set of participants who prepared a salad with chicken breast fillet carrying a known amount of tracer bacteria. The amount of tracer that could be recovered from the salad revealed the transfer and survival of Campylobacter and was used as a measure of hygiene. This was introduced into an existing risk model on Campylobacter in the Netherlands to assess the effect of the information intervention both at the level of exposure and the level of human disease risk. We showed that the information intervention supported by the emotion "disgust" alone had no measurable effect on the health risk. However, when a behavioral cue was embedded within the instruction for the salad preparation, the risk decreased sharply. It is shown that a transdisciplinary approach, involving research on risk perception, microbiology, and risk assessment, is successful in evaluating the efficacy of an information intervention in terms of human health risks. The approach offers a novel tool for science-based risk management in the area of food safety.     

'A Far Friend is Worth More than a Good Neighbour': Proximity and Innovation in a Small Country

Journal of Management and Governance - This paper is about the relationship betweeninnovation and geography. Much of theliterature on regional economics and innovationsuggests that knowledge...