Clinical utility of genetic risk testing in primary care: the example of Type 2 diabetes

Genetics, Nutrition, and Health: A New Frontier in Disease Prevention

The field of nutrition research has traditionally focused on the effects of macronutrients and micronutrients on the body. However, it has become evident that individuals have unique genetic makeups that influence their response to food. Nutritional genomics, which includes nutrigenetics and nutrigenomics, explores the interaction between an individual's genetic makeup, diet, and health outcomes. Nutrigenetics studies the impact of genetic variation on an individual's response to dietary nutrients, while nutrigenomics investigates how dietary components affect gene regulation and expression. These disciplines seek to understand the impact of diet on the genome, transcriptome, proteome, and metabolome. It provides insights into the mechanisms underlying the effect of diet on gene expression. Nutrients can cause the modification of genetic expression through epigenetic changes, such as DNA methylation and histone modifications. The aim of nutrigenomics is to create personalized diets based on the unique metabolic profile of an individual, gut microbiome, and genetic makeup to prevent diseases and promote health. Nutrigenomics has the potential to revolutionize the field of nutrition by combining the practicality of personalized nutrition with knowledge of genetic factors underlying health and disease. Thus, nutrigenomics offers a promising approach to improving health outcomes (in terms of disease prevention) through personalized nutrition strategies based on an individual's genetic and metabolic characteristics.

Advances in Nutrigenomics and Applications in Public Health: A Recent Update

Nutrition research is achieving new paradigms through recent advances in the field of Nutrigenomics. The application of genomic principles for the identification of relationships between certain specific nutrients with genetic factors is termed “Nutrigenomics”. This knowledge is essential to understanding the risk factors behind diet-related chronic degenerative diseases, which further helps resolve the underlying mechanism of genetic predisposition. Advances in Sciences associated with the study of genes have assisted in developing a deep insight into genetic variants, and gene expression patterns to work out therapeutic responses toward chronic degenerative diseases associated with Public Health. To appraise recent advances in Nutrigenomics with its application in Public health several databases including Pub Med, Google Scholar, Medline etc were investigated in detail. A total of 72 relevant peer-reviewed journal articles were included in this review paper. Nutrigenomics has an important role in comprehending how homeostatic control is maintained and the way metabolic pathways are influenced by nutrient intake. The knowledge of Nutrigenomics helps in working out personalized nutrition strategies for both prevention and management of the diseased situation. The present review article aims to investigate and present a piece of in-depth information about the latest Advances in Nutrigenomics and its application in public health.

Incorporation of a genetics-based information module into standardized diabetes patient education

OBJECTIVE

The purpose of this study is to investigate the effectiveness of a genetics educational module created to improve understanding about the genetics of diabetes, assess motivation to engage in healthy lifestyle behaviors, and gauge interest in genetic testing for diabetes.

METHODS

Participants were recruited from the Multidisciplinary Comprehensive Diabetes Clinic at the University of Alabama at Birmingham. Participants completed a pre-survey to assess three domains: (1) knowledge about diabetes etiology and testing, (2) healthy lifestyle behaviors, and (3) interest in genetic testing. Participants viewed a short, recorded educational module, then completed a post-survey to re-assess the domains.

RESULTS

Participants increased knowledge about genetics of diabetes (p < 0.0001) and genetic testing (p = 0.0184), demonstrated motivation to adopt healthy behaviors (p < 0.0001), and decreased interest in genetic testing (p = 0.0833) after viewing the module.

CONCLUSIONS

The educational module increased understanding of diabetes and increased motivation to adopt healthy behaviors. The need for patient-friendly educational modules explaining the genetics of diabetes will likely increase with continued discoveries of how genetics contributes to diabetes risk and outcomes. This short, educational module has the potential to provide genetic information in an effective way that is easily adapted in a routine clinic setting.

Genomics-informed weight management in primary care: anticipated public interest

Aim: An exploratory survey assessed the influence of current and potential future genomic applications for weight management on individuals’ desires to address weight management within primary care. Materials & methods: A convenience sample of 714 US adults aged 18–70 completed an online survey that presented three scenarios: no genomic information; current genomic capabilities; and potential future applications of genomics for weight management. Results: Participants had increased interest in weight management assistance through primary care when considering genomic applications in weight management, p (1,1.68) = 24.66, p < 0.001; this increase was more robust among individuals who felt their weight was important for their health, p (1,1.68) = 20.85, p < 0.001. Conclusion: Primary care systems may need to accommodate a rise in the volume of patients seeking weight management assistance as genomic approaches come to fruition.

Mental Models of Cause and Inheritance for Type 2 Diabetes Among Unaffected Individuals Who Have a Positive Family History

Using the familial risk perception (FRP) model as a framework, we elicited causal and inheritance explanations for type 2 diabetes (T2D) from people who do not have T2D but have a family history for it. We identified four composite mental models for cause of T2D: (a) purely genetic; (b) purely behavioral/environmental; (c) direct multifactorial, in which risk factors interact and over time directly lead to T2D; and (d) indirect multifactorial, in which risk factors interact and over time cause a precursor health condition (such as obesity or metabolic syndrome) that leads to T2D. Interestingly, participants described specific risk factors such as genetics, food habits, lifestyle, weight, and culture as "running in the family." Our findings provide insight into lay beliefs about T2D that can be used by clinicians to anticipate or make sense of responses to questions they pose to patients about mental models for T2D.

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.

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.

Does Type 2 Diabetes Genetic Testing and Counseling Reduce Modifiable Risk Factors? A Randomized Controlled Trial of Veterans

OBJECTIVE

We examined the clinical utility of supplementing type 2 diabetes mellitus (DM) risk counseling with DM genetic test results and counseling.

RESEARCH DESIGN AND METHODS

In this randomized controlled trial, non-diabetic overweight/obese veteran outpatients aged 21 to 65 years received DM risk estimates for lifetime risk, family history, and fasting plasma glucose, followed by either genetic test results (CR+G; N = 303) or control eye disease counseling (CR+EYE; N = 298). All participants received brief lifestyle counseling encouraging weight loss to reduce the risk of DM.

RESULTS

The mean age was 54 years, 53% of participants were black, and 80% were men. There was no difference between arms in weight (estimated mean difference between CR+G vs. CR+EYE at 3 months = 0.2 kg, 95% CI: -0.3 to 0.7; at 6 months = 0.4 kg, 95 % CI: -0.3 to 1.1), insulin resistance, perceived risk, or physical activity at 3 or 6 months. Calorie and fat intake were lower in the CR+G arm at 3 months (p's ≤ 0.05) but not at 6 months (p's > 0.20).

CONCLUSIONS

Providing patients with genetic test results was not more effective in changing patient behavior to reduce the risk of DM compared to conventional risk counseling.

TRIAL REGISTRATION

ClinicalTrials.gov NCT01060540 http://clinicaltrials.gov/show/NCT01060540.

Genomic-based tools for the risk assessment, management, and prevention of type 2 diabetes

Type 2 diabetes (T2D) is a common and serious disorder and is a significant risk factor for the development of cardiovascular disease, neuropathy, nephropathy, retinopathy, periodontal disease, and foot ulcers and amputations. The burden of disease associated with T2D has led to an emphasis on early identification of the millions of individuals at high risk so that management and intervention strategies can be effectively implemented before disease progression begins. With increasing knowledge about the genetic basis of T2D, several genomic-based strategies have been tested for their ability to improve risk assessment, management and prevention. Genetic risk scores have been developed with the intent to more accurately identify those at risk for T2D and to potentially improve motivation and adherence to lifestyle modification programs. In addition, evidence is building that oral antihyperglycemic medications are subject to pharmacogenomic variation in a substantial number of patients, suggesting genomics may soon play a role in determining the most effective therapies. T2D is a complex disease that affects individuals differently, and risk prediction and treatment may be challenging for health care providers. Genomic approaches hold promise for their potential to improve risk prediction and tailor management for individual patients and to contribute to better health outcomes for those with T2D.

Do physicians think genomic medicine will be useful for patient care?

Significant technological improvements over the last decade have led to a vast expansion in the understanding of the genomic architecture of human disease. However, the use of genomic information, so-called genomic medicine, in routine clinical care, has been slow in comparison to the growth in genomic discovery. The uptake of genomic technology into clinical practice will depend on physicians' perspectives of its utility in patient care. We review recent literature addressing physician attitudes regarding the usefulness and limitations of genomic testing. We conclude by proposing research areas to better understand the role physicians will play in the uptake of genomic information into clinical medicine.

Nutrigenomics: definitions and advances of this new science

The search for knowledge regarding healthy/adequate food has increased in the last decades among the world population, researchers, nutritionists, and health professionals. Since ancient times, humans have known that environment and food can interfere with an individual's health condition, and have used food and plants as medicines. With the advance of science, especially after the conclusion of the Human Genome Project (HGP), scientists started questioning if the interaction between genes and food bioactive compounds could positively or negatively influence an individual's health. In order to assess this interaction between genes and nutrients, the term "Nutrigenomics" was created. Hence, Nutrigenomics corresponds to the use of biochemistry, physiology, nutrition, genomics, proteomics, metabolomics, transcriptomics, and epigenomics to seek and explain the existing reciprocal interactions between genes and nutrients at a molecular level. The discovery of these interactions (gene-nutrient) will aid the prescription of customized diets according to each individual's genotype. Thus, it will be possible to mitigate the symptoms of existing diseases or to prevent future illnesses, especially in the area of Nontransmissible Chronic Diseases (NTCDs), which are currently considered an important world public health problem.

The effect of genetic counseling for adult offspring of patients with type 2 diabetes on attitudes toward diabetes and its heredity: a randomized controlled trial

The aim of this study is to investigate the effect of diabetes genetic counseling on attitudes toward diabetes and its heredity in relatives of type 2 diabetes patients. This study was an unmasked, randomized controlled trial at a medical check-up center in Japan. Subjects in this study are healthy adults between 30 and 60 years of age who have a family history of type 2 diabetes in their first degree relatives. Participants in the intervention group received a brief genetic counseling session for approximately 10 min. Genetic counseling was structured based on the Health Belief Model. Both intervention and control groups received a booklet for general diabetes prevention. Risk perception and recognition of diabetes, and attitude towards its prevention were measured at baseline, 1 week and 1 year after genetic counseling. Participants who received genetic counseling showed significantly higher recognition about their sense of control over diabetes onset than control group both at 1 week and 1 year after the session. On the other hand, anxiety about diabetes did not change significantly. The findings show that genetic counseling for diabetes at a medical check center helped adults with diabetes family history understand they are able to exert control over the onset of their disease through lifestyle modification.