Effects of gene-lifestyle interactions on obesity based on a multi-locus risk score: A cross-sectional analysis

The relationship between lifestyle and obesity is a major focus of research. Personalized nutrition, which utilizes evidence from nutrigenomics, such as gene-environment interactions, has been attracting attention in recent years. However, evidence for gene-environment interactions that can inform treatment strategies is lacking, despite some reported interactions involving dietary intake or physical activity. Utilizing gene-lifestyle interactions in practice could aid in optimizing interventions according to genetic risk.

This study aimed to elucidate the effects of gene-lifestyle interactions on body mass index (BMI). Cross-sectional data from the Japan Multi-Institutional Collaborative Cohort Study were used. Interactions between a multi-locus genetic risk score (GRS), calculated from 76 ancestry-specific single nucleotide polymorphisms, and nutritional intake or physical activity were assessed using a linear mixed-effect model.

The mean (standard deviation) BMI and GRS for all participants (n = 12,918) were 22.9 (3.0) kg/m2 and -0.07 (0.16), respectively. The correlation between GRS and BMI was r(12,916) = 0.13 (95% confidence interval [CI] 0.11-0.15, P < 0.001). An interaction between GRS and saturated fatty acid intake was observed (β = -0.11, 95% CI -0.21 to -0.02). An interaction between GRS and n-3 polyunsaturated fatty acids was also observed in the females with normal-weight subgroup (β = -0.12, 95% CI -0.22 to -0.03).

Our results provide evidence of an interaction effect between GRS and nutritional intake and physical activity. This gene-lifestyle interaction provides a basis for developing prevention or treatment interventions for obesity according to individual genetic predisposition.