Model Selection Approach Suggests Causal Association between 25-Hydroxyvitamin D and Colorectal Cancer

Vitamin D deficiency has been associated with increased risk of colorectal cancer (CRC), but causal relationship has not yet been confirmed. We investigate the direction of causation between vitamin D and CRC by extending the conventional approaches to allow pleiotropic relationships and by explicitly modelling unmeasured confounders.Plasma 25-hydroxyvitamin D (25-OHD), genetic variants associated with 25-OHD and CRC, and other relevant information was available for 2645 individuals (1057 CRC cases and 1588 controls) and included in the model. We investigate whether 25-OHD is likely to be causally associated with CRC, or vice versa, by selecting the best modelling hypothesis according to Bayesian predictive scores. We examine consistency for a range of prior assumptions.Model comparison showed preference for the causal association between low 25-OHD and CRC over the reverse causal hypothesis. This was confirmed for posterior mean deviances obtained for both models (11.5 natural log units in favour of the causal model), and also for deviance information criteria (DIC) computed for a range of prior distributions. Overall, models ignoring hidden confounding or pleiotropy had significantly poorer DIC scores.Results suggest causal association between 25-OHD and colorectal cancer, and support the need for randomised clinical trials for further confirmations

Balancing Give and Take: Funding and Accountability in Public Higher Education

Many of the challenges facing postsecondary education today are rooted in lack of resources and money. As state legislatures wrestle with the growing costs of Medicaid, social services, corrections, and K-12 education, state support for higher education remains stagnant. This forces public universities to look to other sources for revenue, including federal and private grants, alumni donations, student tuition and fees, and entrepreneurial enterprises. In turn, these constituent groups place greater expectations and demands on public colleges and universities, further stretching already limited resources. Within this landscape of numerous and sometimes conflicting demands, colleges and universities need to remain accountable to the state government and serve the public good in order to ensure a sufficient and stable level of public funding. At the same time, state governments must maximize the use of limited funds in order to reap the greatest benefits of investing in higher education. To help states and their universities accomplish these monumental tasks, this forum features some of the latest postsecondary education research addressing three fundamental questions: 1. How do states benefit from investing in higher education? 2. What should public universities do to serve the public good and therefore earn and ensure state funding? 3. How do we maximize the investment of limited tax dollars in higher education