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

A randomised controlled trial to determine the effect of genotype-based personalised diet and physical activity advice for FTO genotype (rs9939609) delivered via email on healthy eating motivation in young adults

The prevalence of obesity continues to rise, and public health dietary recommendations are not being adhered to. The transition to higher education is a period of risk for weight gain in young adults and has been demonstrated as a good time to initiate behaviour change. A genotype-based personalised approach to dietary recommendations may motivate young adults to maintain or adopt positive dietary behaviours. The aim of the present study was to determine the efficacy of genotype-based personalised dietary and physical activity advice on healthy eating motivation in young adults. Participants were young adults (n = 153), aged 18-25 years. Baseline measures (participant characteristics, height, weight, body mass index [BMI], body fat percentage [BF%], healthy eating motivation and physical activity) were collected. Participants were genotyped for a SNP in the FTO gene (rs99396090) and randomly allocated (stratified for genotype) to three different groups (1. Genotype-based personalised advice: dietary and physical activity advice based on genotype, BMI and reported physical activity; 2. Non-genotype-based personalised advice: dietary and physical activity advice based on BMI and reported physical activity; 3. Control: no advice). A week after receipt of advice delivered via email, participants completed the healthy eating motivation questionnaire for a second time. Genotype-based personalised dietary advice did not affect healthy eating motivation: when participants were analysed across the whole group (p = 0.417), when analysed according to those informed of a risk or non-risk-associated genotype (p = 0.287), or when analysed according to those with a BMI (>25 kg/m2; p = 0.336) or BF% (male >18%, female >31%; p = 0.387) outside the healthy range. There was also no significant difference in healthy eating motivation at 1-week in the control or non-genotype-based advice groups. Genotype-based personalised advice for the prevention of obesity did not affect healthy eating motivation in this group of healthy, young adults.

Deciphering the causal association and co-disease mechanisms between psoriasis and breast cancer

Background

Prior research has indicated a link between psoriasis and the susceptibility to breast cancer (BC); however, a definitive causal relationship remains elusive. This study sought to elucidate the causal connection and shared underlying mechanisms between psoriasis and BC through bidirectional Mendelian randomization (MR) and bioinformatic approaches.

Methods

We employed a bidirectional MR approach to examine the potential causal connection between psoriasis and BC. Genetic data pertaining to psoriasis and BC were sourced from extensive published genome-wide association studies. The inverse -variance weighted or wald ratio served as the primary method for estimating causal effects. Sensitivity analysis of the MR results was applied with multiple methods. Leveraged datasets from the Gene Expression Omnibus and the Cancer Genome Atlas repositories to identify common differentially expressed genes, shedding light on the shared mechanisms underlying these two conditions.

Results

The MR analysis revealed that when considering psoriasis as an exposure factor, the incidences of BC (OR=1.027) and estrogen receptor negative (ER-) BC (OR=1.054) were higher than in the general population. When using Her2+ BC as an exposure factor, the risk of psoriasis was 0.822 times higher (OR=0.822) than in the general population. Sensitivity analysis indicated that the results were robust. Transcriptome analysis showed that CXCL13 and CCL20 were activated in both BC and psoriasis. Both diseases were also linked to neutrophil chemotaxis, the IL-17 pathway, and the chemokine pathway.

Conclusion

The results suggest that psoriasis may increase the risk of BC, especially ER- BC, while reverse MR suggests a decreased risk of psoriasis in Her2+ BC. Transcriptome analysis revealed a shared mechanism between psoriasis and BC.

Genetically Predicted Causal Effects of Gut Microbiota and Gut Metabolites on Digestive Tract Cancer: A Two-Sample Mendelian Randomization Analysis

Background

Evidence from numerous observational studies and clinical trials has linked gut microbiota and metabolites to digestive tract cancer. However, the causal effect between these factors remains uncertain.

Methods

Data for this study were obtained from the MiBioGen, TwinsUK Registry, and FinnGen (version R8). Two-sample Mendelian randomization analysis with inverse variance weighting method was primarily used, and the results were validated by heterogeneity analysis, pleiotropy test, and sensitivity analysis.

Results

At P < 5 × 10-8, our analysis identified four gut microbiotas as risk factors for digestive tract cancer and six as risk factors for colorectal cancer. Conversely, one gut microbiota exhibited protection against bile duct cancer, and two showed protective effects against stomach cancer. At P < 1 × 10-5, our investigation revealed five, six, three, eight, eight, and eight gut microbiotas as risk factors for esophageal, stomach, bile duct, liver, pancreatic, and colorectal cancers, respectively. In contrast, four, two, eight, two, two, and five gut microbiotas exhibited protective effects against these cancers. Additionally, GABA, a metabolite of gut microbiota, displayed a significant protective effect against colorectal cancer.

Conclusion

In conclusion, specific gut microbiota and metabolites play roles as risk factors or protective factors for digestive tract cancer, and a causal relationship between them has been established, offering novel insights into gut microbiota-mediated cancer development.

Causal relationship between gut microbiota and cancers: a two-sample Mendelian randomisation study

BACKGROUND

Evidence from observational studies and clinical trials suggests that the gut microbiota is associated with cancer. However, the causal association between gut microbiota and cancer remains to be determined.

METHODS

We first identified two sets of gut microbiota based on phylum, class, order, family, and genus level information, and cancer data were obtained from the IEU Open GWAS project. We then performed two-sample Mendelian randomisation (MR) to determine whether the gut microbiota is causally associated with eight cancer types. Furthermore, we performed a bi-directional MR analysis to examine the direction of the causal relations.

RESULTS

We identified 11 causal relationships between genetic liability in the gut microbiome and cancer, including those involving the genus Bifidobacterium. We found 17 strong associations between genetic liability in the gut microbiome and cancer. Moreover, we found 24 associations between genetic liability in the gut microbiome and cancer using multiple datasets.

CONCLUSIONS

Our MR analysis revealed that the gut microbiota was causally associated with cancers and may be useful in providing new insights for further mechanistic and clinical studies of microbiota-mediated cancer.

Brief ‘Appetitive Trait Tailored Intervention’: Development in a Sample of Adults with Overweight and Obesity

Appetitive traits are associated with weight and could be managed using behavioural strategies. Personalised approaches to weight loss could use a person's appetitive trait profile to tailor weight management advice. This study aimed to explore participants’ experiences of a brief Appetitive Trait Tailored Intervention (ATTI) based on participants’ Adult Eating Behaviour Questionnaire (AEBQ) scores. The ATTI was developed using strategies from modified Cognitive Behavioural Therapy and behaviour change techniques. Acceptability testing of the ATTI was carried out with participants (body mass index ≥25) who completed the AEBQ online and were sent their appetitive trait profile and corresponding weight loss tips via e-mail. Participants were asked to follow the tips for 8 weeks and following the tips, perceived helpfulness, barriers, and initial and final body weight. Qualitative interviews explored their experiences. Thirty-seven participants provided feedback and reported the majority of the tips to be helpful. Thirty-two participants (92.5% female) provided their final weight; 10 reported weight loss ≥5% of initial weight. Qualitative interviews (n = 21) revealed that tailoring was seen as novel and participants felt that the ATTI increased their self-awareness and encouraged behavioural changes. The low intensity of the ATTI limited engagement for some. The ATTI is an acceptable, novel approach to weight management.

Impact of diagnostic labels and causal explanations for weight gain on diet intentions, cognitions and emotions: An experimental online study

Disease labels and causal explanations for certain symptoms or conditions have been found to have both positive and negative outcomes. For example, a diagnosis of polycystic ovary syndrome could conceivably motivate a person to engage in weight management, which is the recommended first line treatment. Furthermore, doctors may feel more comfortable discussing weight when linked to a medical condition. However, such a diagnosis may elicit feelings of increased anxiety, perceived severity and reduced sense of control. Mixed findings are also evident for impacts of genetic explanations on psychosocial outcomes and behaviours. Using hypothetical scenarios presented in an online survey, participants were asked to imagine that they were visiting their general practitioner due to experiencing weight gain, irregular periods, and more pimples than usual. Participants were randomised to receive different diagnostic labels ('polycystic ovary syndrome', 'weight' or no label/description) and causal explanations (genetic or environmental) for their symptoms. Primary outcomes assessed included intention to eat a healthier diet and perceived personal control of weight (average score on scale 1-7 across 3 items). Secondary outcomes included weight stigma, blameworthiness, worry, perceived severity, self-esteem, belief diet will reduce risks and menu item choice. Participants were 545 females aged 18-45 years (mean = 33 years), living in Australia, recruited through a national online recruitment panel. The sample was overweight on average (BMI = 26.5). Participants reporting a PCOS diagnosis were excluded from analyses. We found no main effects of the label or explanation on intention to eat healthier or perceived personal control of weight. For secondary outcomes, those given the genetic explanation reported higher weight stigma (range 1-7; MD = 0.27, 95%CI: 0.011,0.522), greater worry (range 1-7; MD = 0.27, 95%CI: 0.037,0.496), lower self-esteem (range 10-40; MD = 1.26, 95%CI: 0.28 to 2.24) and perceived their weight as more severe (range 1-7; MD = 0.28; 95%CI: 0.05,0.52) than those given the environmental explanation, averaged over disease label given. These findings further highlight the deleterious effects of genetic explanations on psychosocial outcomes and reinforce the need for caution when communicating the aetiology of weight-related health issues.

Genetic feedback for psychiatric conditions: Where are we now and where are we going

Genome-wide association studies are rapidly advancing our understanding of the genetic architecture of complex disorders, including many psychiatric conditions such as major depression, schizophrenia, and substance use disorders. One common goal of genome-wide association studies is to use findings for enhanced clinical prediction in the future, which can aid in identifying at-risk individuals to enable more effective prevention screening and treatment strategies. In order to achieve this goal, we first need to gain a better understanding of the issues surrounding the return of complex genetic results. In this article, we summarize the current literature on: (a) genetic literacy in the general population, (b) the public's interest in receiving genetic test results for psychiatric conditions, (c) how individuals react to and interpret their genotypic information for specific psychiatric conditions, and (d) gaps in our knowledge that will be critical to address as we move toward returning genotypic information for psychiatric conditions in both research and clinical settings. By reviewing extant studies, we aim to increase awareness of the potential benefits and consequences of returning genotypic information for psychiatric conditions.

Consensus Report of the Academy of Nutrition and Dietetics: Incorporating Genetic Testing into Nutrition Care

Personalization of nutrition advice is a process already familiar to registered dietitian nutritionists, but it is not yet clear whether incorporating genetic results as an added layer of precision improves nutrition-related outcomes. Therefore, an independent workgroup of experts, supported by the Academy's Evidence Analysis Center staff, conducted a systematic review to examine the level of evidence measuring the effect of incorporating genetic testing results into nutrition counseling and care, compared to an alternative intervention or control group, on nutrition-related outcomes. This systematic review revealed that only weak quality evidence is available in the scientific literature and observed that this field is still maturing. Therefore, at present, there is insufficient scientific evidence to determine whether there are effects of incorporating genetic testing into nutrition practice. The workgroup prepared this Consensus Report based on this systematic review to provide considerations for the practical application of incorporating genetic testing into the nutrition care process.

Benefits and limitations of genome-wide association studies

Genome-wide association studies (GWAS) involve testing genetic variants across the genomes of many individuals to identify genotype-phenotype associations. GWAS have revolutionized the field of complex disease genetics over the past decade, providing numerous compelling associations for human complex traits and diseases. Despite clear successes in identifying novel disease susceptibility genes and biological pathways and in translating these findings into clinical care, GWAS have not been without controversy. Prominent criticisms include concerns that GWAS will eventually implicate the entire genome in disease predisposition and that most association signals reflect variants and genes with no direct biological relevance to disease. In this Review, we comprehensively assess the benefits and limitations of GWAS in human populations and discuss the relevance of performing more GWAS.

Learning one's genetic risk changes physiology independent of actual genetic risk

Millions of people now access personal genetic risk estimates for diseases such as Alzheimer's, cancer and obesity¹. While this information can be informative^2-4, research on placebo and nocebo effects^5-8 suggests that learning of one's genetic risk may evoke physiological changes consistent with the expected risk profile. Here we tested whether merely learning of one's genetic risk for disease alters one's actual risk by making people more likely to exhibit the expected changes in gene-related physiology, behaviour and subjective experience. Individuals were genotyped for actual genetic risk and then randomly assigned to receive either a 'high-risk' or 'protected' genetic test result for obesity via cardiorespiratory exercise capacity (experiment 1, N = 116) or physiological satiety (experiment 2, N = 107) before engaging in a task in which genetic risk was salient. Merely receiving genetic risk information changed individuals' cardiorespiratory physiology, perceived exertion and running endurance during exercise, and changed satiety physiology and perceived fullness after food consumption in a self-fulfilling manner. Effects of perceived genetic risk on outcomes were sometimes greater than the effects associated with actual genetic risk. If simply conveying genetic risk information can alter actual risk, clinicians and ethicists should wrestle with appropriate thresholds for when revealing genetic risk is warranted.

An experiment assessing effects of personalized feedback about genetic susceptibility to obesity on attitudes towards diet and exercise

As increasing attention is paid to possible genetic influences on susceptibility to obesity, recent studies have examined how genetic attributions can impact laypeople's weight-related attitudes and eating behavior. Little consideration, however, has been devoted to understanding the potential effects of learning that one does not have a genetic predisposition to obesity. The present study investigated the possibility that such feedback might bring about negative consequences by making people feel invulnerable to weight gain, which is termed a genetic invincibility effect. After conducting a saliva test disguised as genetic screening, participants were randomly assigned to be told that there was either a very high or very low chance that they carried genes known to increase one's risk of developing obesity. Participants who were told that they were not genetically predisposed to obesity judged the efficacy of healthy diet and exercise habits to be significantly lower than did those who were told that they were genetically predisposed and those who did not receive any genetic feedback. When prompted to select a meal from a menu of options, participants who were told that they were not genetically predisposed to obesity were also more likely than others to select unhealthy foods. These findings demonstrate the existence of a genetic invincibility effect, suggesting that personalized feedback indicating the absence of a genetic liability could have negative psychological consequences with substantial health-related implications.

Recent progress in genetics, epigenetics and metagenomics unveils the pathophysiology of human obesity

In high-, middle- and low-income countries, the rising prevalence of obesity is the underlying cause of numerous health complications and increased mortality. Being a complex and heritable disorder, obesity results from the interplay between genetic susceptibility, epigenetics, metagenomics and the environment. Attempts at understanding the genetic basis of obesity have identified numerous genes associated with syndromic monogenic, non-syndromic monogenic, oligogenic and polygenic obesity. The genetics of leanness are also considered relevant as it mirrors some of obesity's aetiologies. In this report, we summarize ten genetically elucidated obesity syndromes, some of which are involved in ciliary functioning. We comprehensively review 11 monogenic obesity genes identified to date and their role in energy maintenance as part of the leptin-melanocortin pathway. With the emergence of genome-wide association studies over the last decade, 227 genetic variants involved in different biological pathways (central nervous system, food sensing and digestion, adipocyte differentiation, insulin signalling, lipid metabolism, muscle and liver biology, gut microbiota) have been associated with polygenic obesity. Advances in obligatory and facilitated epigenetic variation, and gene-environment interaction studies have partly accounted for the missing heritability of obesity and provided additional insight into its aetiology. The role of gut microbiota in obesity pathophysiology, as well as the 12 genes associated with lipodystrophies is discussed. Furthermore, in an attempt to improve future studies and merge the gap between research and clinical practice, we provide suggestions on how high-throughput '-omic' data can be integrated in order to get closer to the new age of personalized medicine.

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.

A randomized trial Examining The Impact Of Communicating Genetic And Lifestyle Risks For Obesity

OBJECTIVE

Genetic testing for obesity is available directly to consumers, yet little is understood about its behavioral impact and its added value to nongenetic risk communication efforts based on lifestyle factors.

METHODS

A randomized trial examined the short-term impact of providing personalized obesity risk information, using a 2 × 2 factorial design. Participants were recruited from the Coriell Personalized Medicine Collaborative (CPMC) and randomized to receive (1) no risk information (control), (2) genetic risk, (3) lifestyle risk, or (4) combined genetic/lifestyle risks. Baseline and 3-month follow-up survey data were collected. Analyses examined the impact of risk feedback on intentions to lose weight and self-reported weight.

RESULTS

A total of 696 participants completed the study. A significant interaction effect was observed for genetic and lifestyle information on intent to lose weight (P = 0.0150). Those who received genetic risk alone had greater intentions at follow-up, compared with controls (P = 0.0034). The impact of receiving elevated risk information on intentions varied by source and combination of risks presented. Non-elevated genetic risk did not lower intentions. No group differences were observed for self-reported weight.

CONCLUSIONS

Genetic risk information for obesity may add value to lifestyle risk information depending on the context in which it is presented.

The effect of communicating the genetic risk of cardiometabolic disorders on motivation and actual engagement in preventative lifestyle modification and clinical outcome: a systematic review and meta-analysis of randomised controlled trials

Genetic risk prediction of chronic conditions including obesity, diabetes and CVD currently has limited predictive power but its potential to engage healthy behaviour change has been of immense research interest. We aimed to understand whether the latter is indeed true by conducting a systematic review and meta-analysis investigating whether genetic risk communication affects motivation and actual behaviour change towards preventative lifestyle modification. We included all randomised controlled trials (RCT) since 2003 investigating the impact of genetic risk communication on health behaviour to prevent cardiometabolic disease, without restrictions on age, duration of intervention or language. We conducted random-effects meta-analyses for perceived motivation for behaviour change and clinical changes (weight loss) and a narrative analysis for other outcomes. Within the thirteen studies reviewed, five were vignette studies (hypothetical RCT) and seven were clinical RCT. There was no consistent effect of genetic risk on actual motivation for weight loss, perceived motivation for dietary change (control v. genetic risk group standardised mean difference (smd) -0·15; 95 % CI -1·03, 0·73, P=0·74) or actual change in dietary behaviour. Similar results were observed for actual weight loss (control v. high genetic risk SMD 0·29 kg; 95 % CI -0·74, 1·31, P=0·58). This review found no clear or consistent evidence that genetic risk communication alone either raises motivation or translates into actual change in dietary intake or physical activity to reduce the risk of cardiometabolic disorders in adults. Of thirteen studies, eight were at high or unclear risk of bias. Additional larger-scale, high-quality clinical RCT are warranted.

Genomic Information may Inhibit Weight-Related Behavior Change Inclinations Among Individuals in a Fear State

BACKGROUND

As evidence mounts regarding associations between genetics and body weight, it is essential to understand how to communicate this information, and factors like emotion that could moderate the effectiveness of messages.

PURPOSE

We assessed influences of emotion on reactions to weight-related genomic information in a virtual clinical setting.

METHODS

An online representative US sample of overweight women was randomized to receive an emotion induction (anger, fear, or neutral) paired with information about genomic or behavioral influences on weight in an interaction with a virtual doctor.

RESULTS

Receiving genomic information led to reduced attributions of lifestyle causes for weight and behavioral intentions, but only among individuals in a fear state.

CONCLUSIONS

The current study is among the first to reinforce the concern that discussing genomic underpinnings of overweight could undercut health behavior, and highlights the importance of identifying factors like emotion that influence interpretation of genomic information. Clinicaltrials.gov NCT01888913.

Psychological and behavioral effects of genetic risk testing for obesity: a systematic review

BACKGROUND

Interest is growing in the use of genetic risk testing for lifestyle-related chronic diseases, including obesity, to promote health behavior change.

OBJECTIVE

A systematic review of the literature was conducted to determine the effects that genetic risk feedback for obesity may have on psychological and behavioral factors influencing weight.

METHODS

The MEDLINE/PubMed online database was searched using predefined search terms.

RESULTS

The studies revealed that risk feedback may increase motivation to improve health behaviors, especially among individuals at higher genetic risk. Overweight and obese individuals seemed to experience additional psychological benefits when provided an external explanation for their weight status.

CONCLUSION

While the psychological benefits are promising, the clinical utility of genetic risk testing for obesity remains uncertain.

"It runs in my family …": The association of perceived family history with body dissatisfaction and weight bias internalization among overweight women

Aspects of poor body acceptance (BA), such as internalized weight bias and dissatisfaction with one's shape and size, are the strongest predictors of disordered eating and are associated with reduced engagement in healthy behaviors. Perceiving oneself as having a family history of overweight (PFH) could boost BA by increasing attributions for inherited, biological causes of weight. A community sample of 289 women who were overweight from the Washington, DC metropolitan area who were dissatisfied with their current weight (68% Black; 32% White) enrolled in this study in 2012. PFH of overweight was associated with decreased internalized weight bias among white women and marginally increased body shape satisfaction generally. The relationship between PFH and BA was not explained by biological attributions for weight. Perceptions that overweight runs in one's family can be protective with respect to BA. This is suggestive of the potential benefit of integrating family-based approaches into weight management interventions.

Comparison of coronary heart disease genetic assessment with conventional cardiovascular risk assessment in primary care: reflections on a feasibility study

AIM

This study assesses the feasibility of collecting genetic samples and self-reported outcome measures after cardiovascular risk assessment, and presenting the genetic test results to participants.

BACKGROUND

Coronary heart disease (CHD) genetic tests are increasingly available through direct-to-consumer marketing, but their potential clinical impact on cardiovascular risk assessment is unclear.

METHODS

Observational study in 10 British general practices in Central England. A total of 320 individuals, who had completed conventional cardiovascular risk assessment, were offered CHD genetic test, with follow-up outcome questionnaire at eight months for lifestyle change and State-Trait Anxiety.

FINDINGS

A total of 119 (37%) participants returned genetic test specimens, with over a third reporting family history of CHD in a specified relative; 79 (66.4%) were categorized above-average risk on conventional cardiovascular risk assessment, 65 of whom (82.3%) were only average risk on genetic assessment. The dietary fat questionnaire was poorly completed while study participation was not associated with increased anxiety (mean increase in anxiety score=2.1; 95% CI -0.1-4.3; P=0.06).

CONCLUSION

As a feasibility study, over a third of individuals offered genetic testing in primary care, as part of CVD risk assessment, took up the offer. Although intervention did not appear to increase anxiety, this needs further evaluation. To improve generalizability and effect size, future studies should actively engage individuals from wider socio-economic backgrounds who may not have already contemplated lifestyle change. The current research suggests general practitioners will face the clinical challenge of patients presenting with direct-to-consumer genetic results that are inconsistent with conventional cardiovascular risk assessment.

Genetic susceptibility testing and readiness to control weight: Results from a randomized controlled trial

OBJECTIVE

To test the hypothesis that adding obesity gene feedback (FTO) to simple weight control advice at a life stage with raised risk of weight gain (university) increases readiness to control weight.

METHODS

Individually randomized controlled trial comparing the effect of: (i) simple weight control advice plus FTO feedback (FA) and (ii) simple weight control advice only (AO) on readiness to engage with weight control. Differences in stage of change by genotype and differential weight control behaviors were secondary outcomes.

RESULTS

Of 1,016 participants randomized, only 279 completed follow-up, yielding 90% power to detect a small effect for readiness to control weight. As predicted, FA participants were more likely to be in the contemplation stage than AO participants (P = 0.023). Participants receiving higher-risk genetic results were at a higher stage of change than controls (P = 0.003), with a trend toward a higher stage of change than those getting lower-risk results (P = 0.051). Lower-risk results did not decrease weight control intentions compared with controls (P = 0.55). There were no group differences in adherence to recommended weight control behaviors (P = 0.87).

CONCLUSIONS

Adding FTO feedback to weight control advice enhanced readiness to control weight, without evidence for genetic determinism, but had no more effect on behavior than weight control advice alone.

A new approach to assessing affect and the emotional implications of personal genomic testing for common disease risk

AIMS

Personal genomic testing (PGT) for common disease risk is becoming increasingly frequent, but little is known about people's array of emotional reactions to learning their genomic risk profiles and the psychological harms/benefits of PGT. We conducted a study of post-PGT affect, including positive, neutral, and negative states that may arise after testing.

METHODS

A total of 228 healthy adults received PGT for common disease variants and completed a semistructured research interview within 2 weeks of disclosure. The study participants reported how the PGT results made them feel in their own words. Using an iterative coding process, the responses were organized into three broad affective categories: negative, neutral, and positive affect.

RESULTS

Neutral affect was the most prevalent response (53.9%), followed by positive affect (26.9%) and negative affect (19.2%). We found no differences by gender, race, or education.

CONCLUSIONS

While <20% of participants reported negative affect in response to learning their genomic risk profile for common diseases, a majority experienced either neutral or positive emotions. These findings contribute to the growing evidence that PGT does not impose significant psychological harms. Moreover, they point to a need to better link theories and assessments in both emotional and cognitive processing to capitalize on PGT information for healthy behavior change.

Responses to FTO genetic test feedback for obesity in a sample of overweight adults: a qualitative analysis

Current evidence indicates that genetic testing for obesity risk has limited affective or behavioral impact, but few studies have explored the effects among individuals who self-identify as having weight problems. Here, we report findings from in-depth telephone interviews with seven overweight or obese volunteers who were genotyped for one weight-related gene (FTO), which may offer interesting insights into motivations to seek out genetic testing and immediate reactions to it. All participants had a BMI > 25. The gene test identified one participant as homozygous for the 'higher-risk' variant (AA), three heterozygous (AT), and three homozygous for the 'lower-risk' variant (TT) of FTO. All participants said they took part to find an explanation for their personal struggle with weight control. Those with one or two higher-risk variants experienced relief and saw the result as confirming their private assumption that they were susceptible to weight gain for reasons perceived as 'external' to them. However, at the same time, they described themselves as more motivated to overcome their genetic predisposition. Those with lower-risk variants reported brief disappointment, but then focused on alternative explanations, reinforcing the multifactorial nature of obesity. Despite objectively low 'information value,' all individuals derived some 'personal' benefit from FTO genetic test feedback. However, improving education about the multifactorial nature of complex conditions is important to decrease polarized thinking and associated genetic determinism and stigma to derive the greatest benefits of novel genetic technologies for individuals and their health.

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.

Are health professionals ready for direct-to-consumer genetic and genomic testing?

Direct-to-consumer genetic and genomic tests have been offered for over a decade. With the reduction in the cost of sequencing, the options for consumers will increase, with subsequent pressure on health services to interpret data and integrate the results into healthcare management. However, indications are that health professionals are grossly unprepared to deal with requests for support from those who have undertaken direct-to-consumer genetic or genomic tests. While benefits may be derived from patient-driven investigations, distinction needs to be made between the mostly uncertain clinical utility of susceptibility testing and the potential benefits of a reliably interpreted sequencing result. It is essential that we develop strategies, including enhanced professional education, to cope with the potential impact on the health services, rather than ignoring these developments. There may also be implications for the future of genetic counseling, with potential changes in the current paradigm.

P4 medicine: how systems medicine will transform the healthcare sector and society

Ten years ago, the proposition that healthcare is evolving from reactive disease care to care that is predictive, preventive, personalized and participatory was regarded as highly speculative. Today, the core elements of that vision are widely accepted and have been articulated in a series of recent reports by the US Institute of Medicine. Systems approaches to biology and medicine are now beginning to provide patients, consumers and physicians with personalized information about each individual's unique health experience of both health and disease at the molecular, cellular and organ levels. This information will make disease care radically more cost effective by personalizing care to each person's unique biology and by treating the causes rather than the symptoms of disease. It will also provide the basis for concrete action by consumers to improve their health as they observe the impact of lifestyle decisions. Working together in digitally powered familial and affinity networks, consumers will be able to reduce the incidence of the complex chronic diseases that currently account for 75% of disease-care costs in the USA.

'Battling my biology': psychological effects of genetic testing for risk of weight gain

The availability of genetic tests for multifactorial conditions such as obesity raises concerns that higher-risk results could lead to fatalistic reactions or lower-risk results to complacency. No study has investigated the effects of genetic test feedback for the risk of obesity in non-clinical samples. The present study explored psychological and behavioral reactions to genetic test feedback for a weight related gene (FTO) in a volunteer sample (n = 18) using semi-structured interviews. Respondents perceived the gene test result as scientifically objective; removing some of the emotion attached to the issue of weight control. Those who were struggling with weight control reported relief of self-blame. There was no evidence for either complacency or fatalism; all respondents emphasized the importance of lifestyle choices in long-term weight management, although they recognized the role of both genes and environment. Regardless of the test result, respondents evaluated the testing positively and found it motivating and informative. Genetic test feedback for risk of weight gain may offer psychological benefits beyond its objectively limited clinical utility. As the role of genetic counselors is likely to expand, awareness of reasons for genetic testing for common, complex conditions and reactions to the test result is important.

Genetic predisposition to obesity and lifestyle factors--the combined analyses of twenty-six known BMI- and fourteen known waist:hip ratio (WHR)-associated variants in the Finnish Diabetes Prevention Study

Recent genome-wide association studies have identified multiple loci associated with BMI or the waist:hip ratio (WHR). However, evidence on gene-lifestyle interactions is still scarce, and investigation of the effects of well-documented dietary and other lifestyle data is warranted to assess whether genetic risk can be modified by lifestyle. We assessed whether previously established BMI and WHR genetic variants associate with obesity and weight change in the Finnish Diabetes Prevention Study, and whether the associations are modified by dietary factors or physical activity. Individuals (n 459) completed a 3 d food record and were genotyped for twenty-six BMI- and fourteen WHR-related variants. The effects of the variants individually and in combination were investigated in relation to obesity and to 1- and 3-year weight change by calculating genetic risk scores (GRS). The GRS were separately calculated for BMI and the WHR by summing the increasing alleles weighted by their published effect sizes. At baseline, the GRS were not associated with total intakes of energy, macronutrients or fibre. The mean 1- and 3-year weight changes were not affected by the BMI or WHR GRS. During the 3-year follow-up, a trend for higher BMI by the GRS was detected especially in those who reported a diet low in fibre (P for interaction=0·065). Based on the present findings, it appears unlikely that obesity-predisposing variants substantially modify the effect of lifestyle modification on the success of weight reduction in the long term. In addition, these findings suggest that the association between the BMI-related genetic variants and obesity could be modulated by the diet.

The genetics of childhood obesity and interaction with dietary macronutrients

The genes contributing to childhood obesity are categorized into three different types based on distinct genetic and phenotypic characteristics. These types of childhood obesity are represented by rare monogenic forms of syndromic or non-syndromic childhood obesity, and common polygenic childhood obesity. In some cases, genetic susceptibility to these forms of childhood obesity may result from different variations of the same gene. Although the prevalence for rare monogenic forms of childhood obesity has not increased in recent times, the prevalence of common childhood obesity has increased in the United States and developing countries throughout the world during the past few decades. A number of recent genome-wide association studies and mouse model studies have established the identification of susceptibility genes contributing to common childhood obesity. Accumulating evidence suggests that this type of childhood obesity represents a complex metabolic disease resulting from an interaction with environmental factors, including dietary macronutrients. The objective of this article is to provide a review on the origins, mechanisms, and health consequences of obesity susceptibility genes and interaction with dietary macronutrients that predispose to childhood obesity. It is proposed that increased knowledge of these obesity susceptibility genes and interaction with dietary macronutrients will provide valuable insight for individual, family, and community preventative lifestyle intervention, and eventually targeted nutritional and medicinal therapies.

Genetic test feedback with weight control advice: study protocol for a randomized controlled trial

BACKGROUND

Genetic testing for risk of weight gain is already available over the internet despite uncertain benefits and concerns about adverse emotional or behavioral effects. Few studies have assessed the effect of adding genetic test feedback to weight control advice, even though one of the proposed applications of genetic testing is to stimulate preventive action. This study will investigate the motivational effect of adding genetic test feedback to simple weight control advice in a situation where weight gain is relatively common.

METHODS/DESIGN

First-year university students (n = 800) will be randomized to receive either 1) their personal genetic test result for a gene (FTO) related to weight gain susceptibility in addition to a leaflet with simple weight control advice ('Feedback + Advice' group, FA), or 2) only the leaflet containing simple weight control advice ('Advice Only' group, AO).Motivation to avoid weight gain and active use of weight control strategies will be assessed one month after receipt of the leaflet with or without genetic test feedback. Weight and body fat will be measured at baseline and eight months follow-up. We will also assess short-term psychological reactions to the genetic test result. In addition, we will explore interactions between feedback condition and gene test status.

DISCUSSION

We hope to provide a first indication of the clinical utility of weight-related genetic test feedback in the prevention context.

TRIAL REGISTRATION

Current controlled trials ISRCTN91178663.

Fat brains, greedy genes, and parent power: a biobehavioural risk model of child and adult obesity

We live in a world replete with opportunities to overeat highly calorific, palatable foods - yet not everyone becomes obese. Why? We propose that individuals show differences in appetitive traits (e.g. food cue responsiveness, satiety sensitivity) that manifest early in life and predict their eating behaviours and weight trajectories. What determines these traits? Parental feeding restriction is associated with higher child adiposity, pressure to eat with lower adiposity, and both strategies with less healthy eating behaviours, while authoritative feeding styles coincide with more positive outcomes. But, on the whole, twin and family studies argue that nature has a greater influence than nurture on adiposity and eating behaviour, and behavioural investigations of genetic variants that are robustly associated with obesity (e.g. FTO) confirm that genes influence appetite. Meanwhile, a growing body of neuroimaging studies in adults, children and high risk populations suggests that structural and functional variation in brain networks associated with reward, emotion and control might also predict appetite and obesity, and show genetic influence. Together these different strands of evidence support a biobehavioural risk model of obesity development. Parental feeding recommendations should therefore acknowledge the powerful - but modifiable - contribution of genetic and neurological influences to children's eating behaviour.