Rationale/Aims
Obesity is a pandemic disease causing global mortality and morbidity, a complex disorder promoted by gene-environmental interactions. This study shows differences in Body Mass Index (BMI), and Genetics Risk Scores aimed to investigate gene
environmental associations and relationship predisposition to BMI levels within Brazilian immigrant group in Switzerland compared to Brazilian non-immigrants, furthermore, we will compare both groups to the Swiss population and their genetic risk scores against phenotypes to look for evidence of factors that might shape obesity risk in these groups to help other studies further related to genetics and these populations.
Methods Chapter 2 Study 1: 422 males and females aged 18 – 80 years completed an objective measure of BMI, Genetic test, self-report health status, and physical activity questioner.
Methods Chapter 3 Study 2: In Brazilians and the UK Nutritionists/dietitians were recruited to complete a 46-question online survey on knowledge, involvement, perceived benefits and risks, and education regarding nutritional genomics.
Results: This study is the first to examine this relationship in a cross-sectional study using quantitative measures of many variables from Brazilian immigrants living in Switzerland and the Swiss population by contrasting the recently developed weighted GRS and BMI with lifestyle factors. Also demonstrated that a simple weighted genetic score can show trends of the association between individuals or groups at risk for the disease even without detailed clinical follow-up, therefore a genetic risk score can be used as
a predictable clinical tool. However, the weighted GRS may not be a true reflection of BMI genetic risk in Brazilian populations because of the lack of data for this population. Additionally, different lifestyle information was important in allowing the use of a robust statistical method to understand the influence of the genetic risk score on BMI in different countries, especially in such heterogenic populations. Our study demonstrates the likely utility of modeling BMI for new trajectories in future genetic studies and the need for sample sizes from different backgrounds to check for their
ethnicity's genetic makeup. This approach would also allow for harmonization between studies that collected data from immigrants with different ethnical backgrounds in different countries, overall results show the importance of lifestyle and environment was more significant than the genetic scores alone.
As a result of the new developments in the nutrition and genetics sector, the rushing of its commercial applications before the final scientific conclusions, and the importance of nutritionists/dietitians to give nutritional genomics recommendations, professionals specialist in nutritional therapies and clinical applications for the prevention of diseases need to understand the science in order integrate it into practice. The mean knowledge was low and for the highest qualification, reading literature and perceived benefits were all associated with higher total knowledge scores. Also, 43% of the professionals were unlikely or very unlikely to accurately interpret nutrigenomic patients' reports results however they are willing to undergo training. Spearman's correlation resulted in no association between the total knowledge score and the perceived risks score. Similarly, no correlation between the highest qualification and perceived benefits scores nor perceived risks score was noted. Hence, this thesis aims to investigate the knowledge of nutritional genomics and identify factors associated with it among nutritionists/dietitians in the UK and Brazil.
It also provided an overall picture of the involvement, perceived benefits, and risks, and identified training needs in nutrition and genetics and their differences in both countries.
Conclusions: This Thesis data results from environmental, social, and cross-cultural differences in health status differences and BMI levels. in addition, the study showed a major contribution to lifestyle in obesity than genetic risk score, moreover, it alerts
that obesity and chronic diseases are prevalent among immigrants in Switzerland and it is a public health concern. Health education and promotions for the immigrant population in a country where more than 35% of the population are foreigners should
be a priority due the the higher costs of health care in this country. Moreover, Knowledge of nutrition and genetics among nutritionists & dietitians in the UK and Brazil is currently low, and better knowledge is associated with higher qualifications and relevant perceived benefits. The cost and validity of genetic tests and genetic discrimination concerned nutritionists/dietitians the most. Also, they seem interested in deep training and suggested nutritional genomics to become a mandatory undergraduate module in nutrition/dietetic university degrees.
