Predictors of uptake of obesity genetic testing among affected adults

Genetic Testing for Obesity: Implications and Challenges

PURPOSE OF REVIEW

This review summarizes the experimental literature on behavioral outcomes and psychological effects of genetic testing for obesity. Such tests, although of dubious value, are increasingly marketed to the public, and there has been concern that while results may encourage some consumers to increase the healthfulness of their lifestyles, others may interpret feedback in maladaptive ways.

RECENT FINDINGS

Hypothetical vignettes have been used in artificial settings; few studies have investigated outcomes of actual test results. At present, the effects of genetic testing for obesity seem limited to improving consumers' weight control intentions and motivation rather than actual dietary behavior. Evidence for negative psychological consequences is scarce and seems of greater concern for normal weight persons than for those who are overweight. Better research designs carried out in the field rather than the laboratory with more diverse samples are needed.

The role of genes in talking about overweight: An analysis of discourse on genetics, overweight and health risks in relation to nutrigenomics

This study examines whether the assumptions embedded in nutrigenomics, especially the alleged relation between information about personal health risks and healthy behaviour, match how people account for the relation between food, health and genes in everyday life. We draw on discourse analysis to study accounts of overweight in six group interviews with people who are and who are not overweight. The results show potentially contradictory normative orientations towards behavioural explanations of (over)weight. Overt gene accounts are interactionally problematic (in contrast to more indirect accounts such as 'build'), indicating that participants treat 'behaviour' as the normatively appropriate explanation for overweight. At the same time, however, healthy behaviour is an accountable matter, i.e. it is dealt with in interaction as behaviour that is not self-evidently right but requires an explanation. It is discussed how bringing these interactional concerns to the surface is essential for understanding future users' response to nutrigenomics and emergent technologies more in general.

Predictors of genetic testing decisions: a systematic review and critique of the literature

Genetic testing is increasingly available in medical settings and direct-to-consumer. However, the large and growing literature on genetic testing decisions is rife with conflicting findings, inconsistent methodology, and uneven attention across test types and across predictors of genetic testing decisions. Existing reviews of the literature draw broad conclusions but sacrifice nuanced analysis that with a closer look reveals far more inconsistency than homogeny across studies. The goals of this paper are to provide a systematic review of the empirical work on predictors of genetic testing decisions, highlight areas of consistency and inconsistency, and suggest productive directions for future research. We included all studies that provided quantitative analysis of subjective (e.g., perceived risk, perceived benefits of testing) and/or objective (e.g., family history, sociodemographic variables) predictors of genetic testing interest, intentions, or uptake, which produced a sample of 115 studies. From this review, we conclude that self-reported and test-related (as opposed to disorder-related or objective) predictors are relatively consistent across studies but that theoretically-driven efforts to examine testing interest across test types are sorely needed.

Impact of informing overweight individuals about the role of genetics in obesity: an online experimental study

BACKGROUND/AIMS

Increasing public awareness of obesity genetics could have beneficial or harmful effects on overweight individuals. This study examined the impact of genetic information on weight-related cognitions as well as interest in personalized genetic information about obesity among overweight individuals.

METHODS

Online survey respondents (n = 655) were randomly assigned to read either genetic, gene-environment, or nongenetic obesity causal information. Fifty-two percent of the participants were female, 82.4% were White, 45% had an annual income of USD <40,000, and the mean BMI was 32.5. Internalized weight stigma was measured using the Weight Bias Internalization Scale.

RESULTS

Participants in the genetic and gene-environment conditions were more likely to believe genetics increase obesity risk than participants in the nongenetic condition (both p < 0.05); however, they did not differ regarding internalized weight stigma. Sixty-four percent of the participants expressed interest in receiving personalized genetic information about their obesity risk.

CONCLUSION

Dissemination of information about obesity genetics may have neither a beneficial nor a harmful impact on how overweight individuals perceive themselves. Some overweight individuals may be interested in receiving personalized genetic information. The actual effects of obesity genetic information being incorporated into public health messages and of personalized genetic information on obesity prevention and treatment interventions remain to be seen.

Willingness to participate in genomics research and desire for personal results among underrepresented minority patients: a structured interview study

Patients from traditionally underrepresented communities need to be involved in discussions around genomics research including attitudes towards participation and receiving personal results. Structured interviews, including open-ended and closed-ended questions, were conducted with 205 patients in an inner-city hospital outpatient clinic: 48 % of participants self-identified as Black or African American, 29 % Hispanic, 10 % White; 49 % had an annual household income of <$20,000. When the potential for personal results to be returned was not mentioned, 82 % of participants were willing to participate in genomics research. Reasons for willingness fell into four themes: altruism; benefit to family members; personal health benefit; personal curiosity and improving understanding. Reasons for being unwilling fell into five themes: negative perception of research; not personally relevant; negative feelings about procedures (e.g., blood draws); practical barriers; and fear of results. Participants were more likely to report that they would participate in genomics research if personal results were offered than if they were not offered (89 vs. 62 % respectively, p < 0.001). Participants were more interested in receiving personal genomic risk results for cancer, heart disease and type 2 diabetes than obesity (89, 89, 91, 80 % respectively, all p < 0.001). The only characteristic consistently associated with interest in receiving personal results was disease-specific worry. There was considerable willingness to participate in and desire for personal results from genomics research in this sample of predominantly low-income, Hispanic and African American patients. When returning results is not practical, or even when it is, alternatively or additionally providing generic information about genomics and health may also be a valuable commodity to underrepresented minority and other populations considering participating in genomics research.

Psychological responses to genetic testing for weight gain: a vignette study

Genetic testing for obesity risk is increasingly available to the public but few studies have examined motivational or affective reactions. Here we report findings from a "vignette" study investigating reactions to "higher-risk" and "average-risk" results for the obesity-related FTO gene in two groups: a panel sample of individuals with weight concerns, for whom testing may have treatment implications (n = 306, mean age = 45 years, mean BMI = 35) and a student sample (n = 395, mean age = 25 years, mean BMI = 23), for whom testing would have implications for obesity prevention. Participants were given FTO gene information that described higher-risk alleles as linked with modest weight gain and slightly higher risk of obesity. They responded to both higher- and average-risk vignettes, with order randomized. Interest in genetic testing was high overall, and higher in panel respondents than students (93% vs. 78% would "probably" or "definitely" have the test; P < 0.001). In students, a higher-risk result generated higher motivation to change (d = 0.15; P < 0.001), but also slightly higher negative affect (d = 0.03, P < 0.001) and fatalism (d = 0.05, P < 0.001) than an average-risk result. Panel respondents also had higher motivation to change (d = 0.17, P < 0.001) as well as relief about having an explanation for their body weight (d = 0.02, P = 0.013) in the higher-risk condition, but no increase in fatalism or depression. These results suggest that at the level of anticipated responses to FTO gene feedback, higher-risk results had positive motivational effects with minimal changes in negative affect or fatalism. Genetic testing has the potential to be a useful clinical or preventive tool when combined with appropriate information.

Public health genomics: translating obesity genomics research into population health benefits

We examine how a public health genomics framework can be used to move genomic discoveries into clinical and public health practice for obesity prevention and treatment. There are four phases of translational research: T1: discovery to candidate health application; T2: health application to evidence-based practice guidelines; T3: practice guidelines to health practice; and T4: practice to population health impact. Types of multidisciplinary research and knowledge synthesis needed for each phase, as well as the importance of developing and disseminating evidence-based guidelines, are discussed. Because obesity genomics research is mostly in the discovery phase or in the very early phases of translation (T1), the authors present this framework to illustrate the range of translation activities needed to move genomic discoveries in obesity to actual applications that reduce the burden of obesity at the population level.