Introduction: Waist circumference is significantly associated metabolic disease morbidity and mortality, independent of BMI. Characteristics of dietary intakes, such as overall dietary pattern, dietary fibre and fat intake, are recognised as factors associated with waist circumference. Common genetic variants have also been found to explain variation in population susceptibility to having a high waist circumference. However, it is not known whether dietary intakes modify associations between genetic and waist circumference. Therefore, this study's primary aim is to investigate how diet and genetics affect waist circumference across the UK adult’s population. This study secondary aim is to investigate the effect of dietary intake on genetic predisposition to having high waist circumference.
Method: This cross-sectional study analysed data from the Airwave Health Monitoring Study, a UK-based occupational cohort study that included 45,000 participants (from 2004 to 2018). Diet quality was evaluated based on Dietary Approaches to Stop Hypertension. The genetic risk score associated with waist circumference (GRSwaist) was derived from 91 WC-associated single nucleotide polymorphisms. Multivariable regression models were used to determine the associations between diet, genetics and waist circumference. An interaction term was introduced to multivariable regression models to determine the effect of dietary intake on genetic predisposition to waist circumference. This study was replicated using 442,583 participants from the UK-Biobank Cohort study.
Results: Groups with a larger waist circumference (female > 80 cm, males > 94 cm) was positively associated with HbA1c% (OR= 1.08, 95%CI =1.0,1.1, P-value= 0.02). DASH-diet score and fibre intake were negatively associated with waist circumference. A positive association was found between GRSwaist and waist circumference. No interaction was observed between diet scores and genetic predisposition to having high waist circumference. The replicated analysis on the UK-Biobank population was consistent with the Airwave study findings.
Conclusion: Waist circumference was positively associated with HbA1c%. Dietary patterns and genetic risk scores are significant factors associated with waist circumference in the UK adults’ population. Dietary intake does not modify the influence of genetic on waist circumference.