First‐event or marginal estimation of cause‐specific hazards for analysing correlated multivariate failure‐time data?

In the analysis of multivariate failure-time data, the effect of a treatment or an exposure on the hazard of each failure type is sometimes evaluated using only the information on the first event that occurs in every individual, ignoring all events that follow. A Cox proportional hazards model may be fitted to such data, yielding a cause-specific hazard ratio (HR) estimate of the exposure for each failure type conditional on surviving all other failure types. However, such an estimate would not fully utilize all the available information on event times. Alternatively, a marginal approach may be implemented to model the time distribution of each failure type beyond the subject's first failure to (any) second and later failures. We investigate the performance of these two approaches by simulating positive and negative correlated event times from exponential distributions. Surprisingly, our results suggest that the first-event-only method (when multiple failures are possible) performs as well as the marginal method in most practical situations. Generally, for a modest sample size of 400, it is possible to achieve at least 85 per cent coverage of the true marginal HR with the first-event method. Although the coverage is poor for a correlation of 0.7 and beyond, such a high correlation between competing event times may be biologically rather implausible.     

Human health risks from arsenic in soils: does one model fit all?

In the absence of a "soil model" on arsenic bioavailability, many investigators conducting baseline risk assessments of arsenic-enriched sites have assumed that all arsenic present in the soil is bioavailable. This assumption overestimates actual human health risk because various geochemical forms of arsenic are stable, or insoluble, in human digestive juices. The authors conducted a laboratory incubation study to analyze the in vitro bioavailability of arsenic in soils as a function of soil properties. Four different soil types were selected on the basis of their potential differences with respect to arsenic reactivity. Each soil was amended with sodium arsenite at a rate representative of a routine 1-yr application of arsenical pesticide in an agricultural system. The soils were incubated for 1 yr, after which the authors measured soil-specific total and bioavailable arsenic concentrations. Results demonstrated that soil physicochemical properties significantly affect arsenic bioavailability, and hence estimates of cancer risk, which in turn affect site cleanup cost projections.     

Testing the evolution process of prostate‐specific antigen in early stage prostate cancer: what is the proper underlying model?

This paper empirically tests a model of stochastic evolutions of prostate-specific antigen (PSA), a trigger for intervention in an early stage prostate cancer surveillance program. It conducts hypothesis testing of the Geometric Browning Motion model based on its attributes of independent increments and linearity of the variance in the increment length versus a wide range of stochastic and deterministic alternatives. These alternatives include the currently accepted deterministic growth model. The paper reports strong empirical evidence in favour of the Geometric Browning Motion model. A model that best describes PSA evolution is a prerequisite to the establishment of decision-making criteria for abandoning active surveillance (i.e. a strategy that involves close monitoring) in early stage prostate cancer. Thus, establishing empirically the type of PSA process is a first step toward the identification of more accurate triggers for abandoning active surveillance and starting treatment while the chances of curing the disease are still high.     

Can managers empower nurse‐midwives to improve maternal health care? A comparison of two resource‐poor hospitals in Tanzania

Maternal mortality is very high in Tanzania. Competent hospital care is key to improving maternal outcomes, but there is a crisis of availability and performance of health workers in maternal care. This article uses interviews with managers, nurse‐midwives, and women who had given birth in two hospitals providing virtually all the emergency maternal care in one Tanzania city. It contrasts women's experience in the two hospitals, and analyses interconnections with nurse‐midwives' and managers' experiences of working conditions. The conceptual literature on nurse empowerment identifies some key explanatory variables for these contrasts. Staff experienced less frustration and constraint in one of the hospitals; had more access to structurally empowering resources; and experienced greater congruence between job commitment and working culture, resulting in better work engagement. Conversely, nurse‐midwives in the other hospital were constrained by supply shortages and recurrent lack of support. Contrasting management styles and their impacts demonstrate that even in severely resource‐constrained environments, there is room for management to empower staff to improve maternal care. Empowering management practices include participatory management, supportive supervision, better incentives, and clear leadership concerning ward culture. Structural constraints beyond the capacity of health facility managers must however also be addressed. © 2015 The Authors. International Journal of Health Planning and Management published by John Wiley & Sons, Ltd.     

‘Responsible drinking’ programs and the alcohol industry in Brazil: Killing two birds with one stone?

Over the last decade, the Brazilian alcohol industry - which for years has ignored alcohol problems - inaugurated responsible drinking programs (RDPs). This paper reports findings from an exploratory study that investigated the RDP-related activities of six leading alcohol companies in Brazil (three national, three transnational) focusing on program goals and components, target populations and evaluation methods. Interviews were conducted from October 2007 to February 2008 with nine key-informants, and 71 corporate documents were collected along with additional web information about the programs. Content analysis of interviews and institutional documents was used to identify the companies' RDP activities. Three types of RDPs were found that focused respectively on institutional action, drinking and driving, and underage drinking. All three transnational firms were involved in RDPs, whereas national firms demonstrated limited involvement. The majority of RDPs were implemented using television. No targeted research appears to have been undertaken by the companies to assess the efficacy of the strategies in terms of changes in drinking behavior. The evidence for both national and transnational firms means that is difficult to confirm that the responsible drinking programs produced so far in Brazil have been undertaken to systematically reduce alcohol problems, or mainly as part of a public relations strategy to reduce criticism and potentially forestall government regulations (Babor, 2006, 2009; Jernigan, 2009).     

Reduce dimension or reduce weights? Comparing two approaches to multi‐arm studies in network meta‐analysis

Network meta‐analysis is a statistical method combining information from randomised trials that compare two or more treatments for a given medical condition. Consistent treatment effects are estimated for all possible treatment comparisons. For estimation, weighted least squares regression that in a natural way generalises standard pairwise meta‐analysis can be used. Typically, as part of the network, multi‐arm studies are found. In a multi‐arm study, observed pairwise comparisons are correlated, which must be accounted for. To this aim, two methods have been proposed, a standard regression approach and a new approach coming from graph theory and based on contrast‐based data (Rücker 2012). In the standard approach, the dimension of the design matrix is appropriately reduced until it is invertible (‘reduce dimension’). In the alternative approach, the weights of comparisons coming from multi‐arm studies are appropriately reduced (‘reduce weights’). As it was unclear, to date, how these approaches are related to each other, we give a mathematical proof that both approaches lead to identical estimates. The ‘reduce weights’ approach can be interpreted as the construction of a network of independent two‐arm studies, which is basically equivalent to the given network with multi‐arm studies. Thus, a simple random‐effects model is obtained, with one additional parameter for a common heterogeneity variance. This is applied to a systematic review in depression. Copyright © 2014 John Wiley & Sons, Ltd.     

What explains away the increased risk of histological chorioamnionitis in African‐American mothers of very‐low‐birthweight infants?

We sought explanations for African-American mothers' increased risk of chorioamnionitis by sequentially adjusting for confounder variables both individually and in groups. We searched for a subset of covariates that had the most influence on the chorioamnionitis odds ratio (OR) of these women. The sample consisted of 305 African-American and 520 White mothers who gave birth to a very-low-birthweight (< or = 1500 g) infant between 1991 and 1993, whose placenta was examined according to protocol and whose hospital chart was reviewed. Histologically proven chorioamnionitis was present in 43% of the placentas from African-American women and in 27% of those from Whites (crude OR 2.1, 95% confidence interval 1.5, 2.8). Singleton status appeared to be the most important effect modifier, with significant crude ORs of 1.5 among singletons and 3.4 among non-singletons. Using logistic regression models in the whole sample and in subgroups, we sought to 'explain away' this increased risk. Indeed, addition of information about confounder variables resulted in considerable reduction in the ORs to 1.1 among singletons and 1.9 among non-singletons. Particularly important among the confounders were singleton birth, Medicaid insurance, duration of ruptured membranes and gestational age. We discuss the possibility that this set of confounding variables conveys, in part, the same information as the variable African-American, and also perhaps information about the availability and/or utilisation of prenatal health care.     

Is the doctrine of double effect irrelevant in end‐of‐life decision making?

In this paper, we consider three arguments for the irrelevance of the doctrine of double effect in end‐of‐life decision making. The third argument is our own and, to that extent, we seek to defend it. The first argument is that end‐of‐life decisions do not in fact shorten lives and that therefore there is no need for the doctrine in justification of these decisions. We reject this argument; some end‐of‐life decisions clearly shorten lives. The second is that the doctrine of double effect is not recognized in UK law (and similar jurisdictions); therefore, clinicians cannot use it as the basis for justification of their decisions. Against this we suggest that while the doctrine might have dubious legal grounds, it could be of relevance in some ways, e.g. in marking the boundary between acceptable and unacceptable practice in relation to the clinician's duty to relieve pain and suffering. The third is that the doctrine is irrelevant because it requires there to be a bad effect that needs justification. This is not the case in end‐of‐life care for patients diagnosed as dying. Here, bringing about a satisfactory dying process for a patient is a good effect, not a bad one. What matters is that patients die without pain and suffering. This marks a crucial departure from the double‐effect doctrine; if the patient's death is not a bad effect then the doctrine is clearly irrelevant. A diagnosis of dying allows clinicians to focus on good dying and not to worry about whether their intervention affects the time of death. For a patient diagnosed as dying, time of death is rarely important. In our conclusion we suggest that acceptance of our argument might be problematic for opponents of physician‐assisted death. We suggest one way in which these opponents might argue for a distinction between such practice and palliative care; this relies on the double‐effect doctrine's distinction between foresight and intention.     

Embodiment without bodies? Analysis of embodiment in US‐based pro‐breastfeeding and anti‐male circumcision movements

This article uses the cases of pro‐breastfeeding and anti‐circumcision activism to complicate the prevailing conceptualisation of embodiment in research on embodied health movements (EHMs). Whereas most EHM activists draw on their own bodily experiences, in the breastfeeding and circumcision movements, embodiment by proxy is common. Activists use embodiment as a strategy but draw on physical sensations that they imagine for other people's bodies, rather than on those they experience themselves. Pro‐breastfeeding activists, who seldom disclose whether they were themselves breastfed, target mothers, encouraging them to breastfeed rather than to formula feed their children in order to reduce their child's risk of disease. Anti‐circumcision activists, only some of whom are circumcised men, urge parents to leave their sons' penises intact in order to avoid illness and disfigurement and to preserve the sons' rights to make their own informed decisions as adults. In both movements activists use embodiment as a persuasive strategy even though they themselves do not necessarily embody the risks of the negative health outcomes with which they are concerned. Future research on EHMs should reconceptualise EHMs to include embodiment by proxy and examine whether this important phenomenon systematically affects movement strategies and outcomes.     

Income‐rich and wealth‐poor? The impact of measures of socio‐economic status in the analysis of the distribution of long‐term care use among older people

This article aims to investigate the impact of using 2 measures of socio‐economic status on the analysis of how informal care and home care use are distributed among older people living in the community. Using data from the Survey of Health, Ageing and Retirement in Europe for 14 European countries, we estimate differences in corrected concentration indices for use of informal care and home care, using equivalised household net income and equivalised net worth (as a proxy for wealth). We also calculate horizontal inequity indices using both measures of socio‐economic status and accounting for differences in need. The findings show that using wealth as a ranking variable results, as a rule, in a less pro‐poor inequality of use for both informal and home care. Once differences in need are controlled for (horizontal inequity), wealth still results in a less pro‐poor distribution for informal care, in comparison with income, whereas the opposite is observed for home care. Possible explanations for these differences and research and policy implications are discussed.     

Can Australia eliminate TB? Modelling immigration strategies for reaching MDG targets in a low‐transmission setting

Background: The 2050 Millennium Development Goals (MDG) for tuberculosis (TB) aim for elimination of TB as a public health issue. We used a mathematical modelling approach to evaluate the feasibility of this target in a low‐prevalence setting with immigration‐related strategies directed at latent tuberculosis. Methods: We used a stochastic individual‐based model to simulate tuberculosis disease among immigrants to Victoria, Australia; a representative low‐transmission setting. A variety of screening and treatment approaches aimed at preventing reactivation of latent infection were applied to evaluate overall tuberculosis incidence reduction and rates of multidrug resistant disease. Results: Without additional intervention, tuberculosis incidence was predicted to reach 34.5 cases/million by 2050. Strategies involving the introduction of an available screening/treatment combination reduced TB incidence to between 16.9–23.8 cases/million, and required screening of 136–427 new arrivals for each case of TB prevented. Limiting screening to higher incidence regions of origin was less effective but more efficient. Conclusions: Public health strategies targeting latent tuberculosis infection in immigrants may substantially reduce tuberculosis incidence in a low prevalence region. However, immigration‐focused strategies cannot achieve the 2050 MDG and alternative or complementary approaches are required.     

Do overeducated individuals have increased risks of ill health?: a Swedish population‐based cohort study

Previous studies indicate that the increasing educational level in many post‐industrial nations may imply that subgroups of the population work in occupations for which they are overeducated. We aimed to investigate whether overeducation is associated with future self‐rated health and psychological distress. The analytical sample consisted of 21,159 participants from the Stockholm Public Health Cohort. Individuals with upper secondary or university education, who in 2006 or 2007 had occupations requiring less education, were considered overeducated. The outcomes were self‐rated health (SRH) and psychological distress in 2010. Overeducated women had an increased risk of less than good SRH, compared to university‐educated women in matching occupations (adjusted odds ratios (OR): 2.44 confidence intervals (CI): 1.32–4.51 for overeducated women with secondary school education), but not compared to less educated women in the same occupational class (adjusted OR: 0.87 CI:0.32–2.38 for overeducated women with secondary school education). We found no increased risk of less than good SRH for overeducated men, and no association between overeducation and psychological distress for either sex. The results indicate that overeducation is not per se associated with onset of less than good SRH or psychological distress in a short‐term perspective, and the findings support education expansion as a means of improving public health.