Challenges in assessing the sunscreen-melanoma association

Source at https://doi.org/10.1002/ijc.31997.Whether sunscreen use affects melanoma risk has been widely studied with contradictory results. To answer this question we performed a systematic review of all published studies, accounting for sources of heterogeneity and bias. We searched for original articles investigating the sunscreen‐melanoma association in humans to February 28, 2018. We then used random‐effects meta‐analysis to combine estimates of the association, stratified by study design. Stratified meta‐analysis and meta‐regression were used to identify sources of heterogeneity. We included 21,069 melanoma cases from 28 studies published 1979–2018: 23 case–control (11 hospital‐based, 12 population‐based), 1 ecological, 3 cohort and 1 randomised controlled trial (RCT). There was marked heterogeneity across study designs and among case–control studies but adjustment for confounding by sun exposure, sunburns and phenotype systematically moved estimates toward decreased melanoma risk among sunscreen users. Ever‐ vs. never‐use of sunscreen was inversely associated with melanoma in hospital‐based case–control studies (adjusted odds ratio (OR) = 0.57, 95%confidence interval (CI) 0.37–0.87, Pheterogeneity Pheterogeneity Pheterogeneity = 0.236). The association differed by latitude (Pinteraction = 0.042), region (Pinteraction = 0.008), adjustment for naevi/freckling (Pinteraction = 0.035), and proportion of never‐sunscreen‐users (Pinteraction = 0·012). Evidence from observational studies on sunscreen use and melanoma risk was weak and heterogeneous, consistent with the challenges of controlling for innate confounding by indication. The only RCT showed a protective effect of sunscreen

Estimating bank default with generalised extreme value regression models

The paper proposes a novel model for the prediction of bank failures, on the basis of both macroeconomic and bank-specific microeconomic factors. As bank failures are rare, in the paper we apply a regression method for binary data based on extreme value theory, which turns out to be more effective than classical logistic regression models, as it better leverages the information in the tail of the default distribution. The application of this model to the occurrence of bank defaults in a highly bank dependent economy (Italy) shows that, while microeconomic factors as well as regulatory capital are significant to explain proper failures, macroeconomic factors are relevant only when failures are defined not only in terms of actual defaults but also in terms of mergers and acquisitions. In terms of predictive accuracy, the model based on extreme value theory outperforms classical logistic regression models

Strategies for dissecting epigenetic mechanisms in the mouse

Epigenetics generally refers to heritable changes in gene expression that are independent of nucleotide sequence. With complete genome sequences in hand, understanding the epigenetic control of genomes is the next step towards comprehending how the same DNA sequence gives rise to different cells, lineages and organs. Epigenetics also contributes to individual variation in normal biology and in disease states. The mouse provides a unique opportunity to understand how epigenetic differences contribute to both development and disease in a tractable mammalian system. Here we discuss current approaches and protocols used to study epigenetics in the mouse, including loss-of-function studies, mutagenesis screens, somatic cell nuclear transfer, genomics and proteomics