Perceived risk of type 2 diabetes: Using linked genomic, clinical and questionnaire data to understand the potential use of genetic risk tools in British South Asians

Abstract

BackgroundDespite growing interest surrounding the integration of genetic risk tools such as polygenic risk scores (PRSs) into routine care for early disease identification and management, major questions remain about whether and how these tools are to be implemented at-scale. Many interventions have explored their use in encouraging the adoption of preventative health behaviours—yet existing evidence remains undetermined, limited by the focus on White European populations. The present study used structural equation modelling to explore genetic risk perceptions surrounding type 2 diabetes (T2D) in a sample of British Bangladeshi and British Pakistani volunteers—combining questionnaire data alongside genomic and clinical information to identify the characteristics of individuals who are likely to act on genetic risk information.Methods and findingsWe conducted this study with volunteers enrolled in Genes & Health—a large-scale (n > 60,000) study in the UK recruiting British Bangladeshi and British Pakistani volunteers from community and NHS settings. Eligible participants between the ages of 16 to 59 years were invited to complete a 15-minute questionnaire containing measures of genetic risk perceptions surrounding T2D, as well as intention to adopt health behaviours and that can prevent or delay T2D. Questionnaire responses were then integrated with participants’ genomic and clinical data available at Genes & Health to construct a model—characterising their mediating relationships in informing participants’ intention.626 participants responded to the questionnaire (response rate = 17%, 37.70% aged 46 to 59 years, 62.62% female). Being between the ages of 46 to 59 years (β = 0.52, 95% CI [0.26, 0.79], p < 0.05), having greater self-reported perceived control over health (β = 0.41, 95% CI [0.26, 0.56], p < 0.05) and interest in genetic testing (β = 0.62, 95% CI [0.46, 0.78], p < 0.05) all had direct positive effects on participants’ intention. Household income showed an indirect effect on intention, mediated by interest in genetic testing, β = 0.24, 95% CI [0.12, 0.37]. Self-identified ethnicity also demonstrated indirect effects on intention via two mediating pathways—both involving participants’ actual T2D PRSs and self-reported family history of T2D (β = 0.03, 95% CI [0.02, 0.05] and β = 0.002, 95% CI [0.001, 0.01]).ConclusionsOur results showed that older age, greater perceived control over health and interest in genetic testing are all predictive of participants’ likelihood of adopting preventative heath behaviours in response to genetic risk information about T2D. We also found evidence pointing to the roles that wider socio-demographic, clinical and familial variables can play in informing and mediating genetic risk perceptions. These findings should raise awareness about potential challenges to the equitable delivery and management of genetic risk tools—and strengthen calls for wider family- and system-level approaches that can help address potential health inequalities, as efforts surrounding the large-scale implementation of genomics into existing health systems continue to grow.Author summaryWhy was this study done?Type 2 diabetes (T2D) disproportionately affects populations of South Asian ancestry.The integration of genetic risk tools such as polygenic risk scores (PRSs) into routine care has been widely discussed—and presents potential clinical utility in the early identification and management of T2D in British Bangladeshi and British Pakistani populations.Studies have explored the use of PRSs in shifting individuals’ genetic risk perceptions and/or encouraging the adoption of preventative health behaviours—yet existing evidence is limited by the focus on older and healthier White European populations.What did the researchers do and find?Combining questionnaire responses with genomic and clinical data in a sample of British Bangladeshi and British Pakistani volunteers, we applied structural equation modelling to analyse their mediating relationships—and to identify the characteristics of individuals who are likely to act on genetic risk information about T2D.Older participants in our sample reported greater levels of intention to adopt health behaviours that can prevent or delay T2D—however, most participants (34.5%) also indicated interest in finding out about genetic risk for T2D at younger ages.We found that relationships between participants’ actual and perceived risk for T2D were predominantly mediated by having first degree family member(s) with T2D history, compared to other clinical variables such as BMI or comorbidities.There were also mediating effects between participants’ self-reported household income and interest in genetic testing in predicting their likelihood of adopting preventative heath behaviours in response to genetic risk information about T2D.What do these findings mean?Upstream determinants and contextual factors such as socio-demographic characteristics and family history of disease can play important roles in leveraging the use of genetic testing for T2D in British Bangladeshi and British Pakistani populations.As efforts around the large-scale implementation of genomics into routine care continue to grow, future work should explore ways to integrate wider family- and system-level approaches that can help address potential health inequalities.It will also be important to consider how strategies can be tailored to younger age groups— given possible discordance between the age at which individuals would want to find out about genetic risk information, versus the age at which they would actually be willing to implement preventative lifestyle changes.