Implications of the HIV testing protocol for refusal bias in seroprevalence surveys

BACKGROUND: HIV serosurveys have become important sources of HIV prevalence estimates, but these estimates may be biased because of refusals and other forms of non-response. We investigate the effect of the post-test counseling study protocol on bias due to the refusal to be tested. METHODS: Data come from a nine-month prospective study of hospital admissions in Addis Ababa during which patients were approached for an HIV test. Patients had the choice between three consent levels: testing and post-test counseling (including the return of HIV test results), testing without post-test counseling, and total refusal. For all patients, information was collected on basic sociodemographic background characteristics as well as admission diagnosis. The three consent levels are used to mimic refusal bias in serosurveys with different post-test counseling study protocols. We first investigate the covariates of consent for testing. Second, we quantify refusal bias in HIV prevalence estimates using Heckman regression models that account for sample selection. RESULTS: Refusal to be tested positively correlates with admission diagnosis (and thus HIV status), but the magnitude of refusal bias in HIV prevalence surveys depends on the study protocol. Bias is larger when post-test counseling and the return of HIV test results is a prerequisite of study participation (compared to a protocol where test results are not returned to study participants, or, where there is an explicit provision for respondents to forego post-test counseling). We also find that consent for testing increased following the introduction of antiretroviral therapy in Ethiopia. Other covariates of refusal are age (non-linear effect), gender (higher refusal rates in men), marital status (lowest refusal rates in singles), educational status (refusal rate increases with educational attainment), and counselor. CONCLUSION: The protocol for post-test counseling and the return of HIV test results to study participants is an important consideration in HIV prevalence surveys that wish to minimize refusal bias. The availability of ART is likely to reduce refusal rates

Bank regulation and systemic risk: cross country evidence

Using data for banks from 65 countries for the period 2001–2013, we investigate the impact of bank regulation and supervision on individual banks’ systemic risk. Our cross-country empirical findings show that bank activity restriction, initial capital stringency and prompt corrective action are all positively related to systemic risk, measured by Marginal Expected Shortfall. We use the staggered timing of the implementation of Basel II regulation across countries as an exogenous event and use latitude for instrumental variable analysis to alleviate the endogeneity concern. Our results also hold for various robustness tests. We further find that the level of equity banks can alleviate such effect, while bank size is likely to enhance the effect, supporting our conjecture that the impact of bank regulation and supervision on systemic risk is through bank’s capital shortfall. Our results do not argue against bank regulation, but rather focus on the design and implementation of regulation

From gut dysbiosis to altered brain function and mental illness: mechanisms and pathways

The human body hosts an enormous abundance and diversity of microbes, which perform a range of essential and beneficial functions. Our appreciation of the importance of these microbial communities to many aspects of human physiology has grown dramatically in recent years. We know, for example, that animals raised in a germ-free environment exhibit substantially altered immune and metabolic function, while the disruption of commensal microbiota in humans is associated with the development of a growing number of diseases. Evidence is now emerging that, through interactions with the gut-brain axis, the bidirectional communication system between the central nervous system and the gastrointestinal tract, the gut microbiome can also influence neural development, cognition and behaviour, with recent evidence that changes in behaviour alter gut microbiota composition, while modifications of the microbiome can induce depressive-like behaviours. Although an association between enteropathy and certain psychiatric conditions has long been recognized, it now appears that gut microbes represent direct mediators of psychopathology. Here, we examine roles of gut microbiome in shaping brain development and neurological function, and the mechanisms by which it can contribute to mental illness. Further, we discuss how the insight provided by this new and exciting field of research can inform care and provide a basis for the design of novel, microbiota-targeted, therapies.GB Rogers, DJ Keating, RL Young, M-L Wong, J Licinio, and S Wesseling

Recent Innovation in the Regulation of Covered Bonds in Europe: Who Will Benefit from the New Legislative Framework?

Covered bonds are debt instruments issued by financial institutions that represent the link between the funding strategies of banks and the capability of originating high-quality assets, which in turn enable cost-efficiently funded lending to the real economy. To date, the regulation of covered bonds has taken place at the national level, resulting in different national approaches regarding key technical issues. The EU (European Union) Parliament and the Council of the European Union have recently harmonised national rules on their issuance by providing common definitions, characteristics and regulations with a view to the use of a European trademark. In this chapter, we intend to explore the new European characteristics of these financial instruments and the possibilities for banks and investors to take advantage of the new regulations