Candidate gene identification following linkage: Search for hypertension susceptibility genes

Following up genetic linkage studies to identify the underlying susceptibility gene(s) for complex disease traits is an arduous yet biologically and clinically important task. Complex traits, such as hypertension, are considered polygenic with many genes influencing risk, each with small effects. Chromosome 2 has been consistently identified as a genomic region with genetic linkage evidence suggesting that one or more loci contribute to blood pressure levels and hypertension status. Using combined positional candidate gene methods, the Family Blood Pressure Program has concentrated efforts in investigating this region of chromosome 2 in an effort to identify underlying candidate hypertension susceptibility gene(s). Initial informatics efforts identified the boundaries of the region and the known genes within it. A total of 82 polymorphic sites in eight positional candidate genes were genotyped in a large hypothesis-generating sample consisting of 1640 African Americans, 1339 whites, and 1616 Mexican Americans. To adjust for multiple comparisons, resampling-based false discovery adjustment was applied, extending traditional resampling methods to sibship samples. Following this adjustment for multiple comparisons, SLC4A5, a sodium bicarbonate transporter, was identified as a primary candidate gene for hypertension. Polymorphisms in SLC4A5 were subsequently genotyped and analyzed for validation in two populations of African Americans (N = 461; N = 778) and two of whites (N = 550; N = 967). Again, SNPs within SLC4A5 were significantly associated with blood pressure levels and hypertension status. While not identifying a single causal DNA sequence variation that is significantly associated with blood pressure levels and hypertension status across all samples, the results further implicate SLC4A5 as a candidate hypertension susceptibility gene, validating previous evidence for one or more genes on chromosome 2 that influence hypertension related phenotypes in the population-at-large. The methodology and results reported provide a case study of one approach for following up the results of genetic linkage analyses to identify genes influencing complex traits. ^

Marketing physical activity and healthy eating: A literature review of recent social marketing campaigns and development of a social marketing plan for the CATCH program

Background. This culminating experience project was inspired by an independent study conducted at The University of Texas School of Public Health with Dr. Andrew Springer, DrPH, who works on the evaluation of the Coordinated Approach to Child Health (CATCH) program in Travis County, Texas. It was indicated that a social marketing plan could enhance current efforts for the CATCH program. The aims of the project were to (1) review and synthesize literature on social marketing, with a specific focus on diet, physical activity, and obesity prevention; and (2) apply the gained knowledge toward a practical solution – a social marketing plan for the CATCH program.^ Methods. The literature review aimed to answer the following questions: (1) What audiences (ethnic and age groups), settings, health behaviors, and behavioral science theories have been used in social marketing campaigns? (2) What features of social marketing were used (e.g. formative research, segmentation, and the marketing mix - including promotional strategies and communication channels)? (3) What were the outcomes of the social marketing campaigns? The search aimed to identify studies that met the following inclusion criteria: (a) The study explicitly stated that social marketing was used; (b) The intervention promoted physical activity and/or healthy eating; (c) The population was children, adolescents, young adults, and/or parents; (d) Results of the intervention were available in the published literature The literature review includes studies from the past five years (2004 to 2009). After reviewing the social marketing literature, the insight and knowledge gained was applied to develop a social marketing plan for the CATCH program. The plan was guided by Hands-on Social Marketing, A Step-by-Step Guide and the Center for Disease Control and Prevention's Social Marketing web course.^