Genotype-by-Environment Interactions in Nonalcoholic Fatty Liver Disease and Chronic Illness among Mexican Americans: The Role of Acculturation Stress

Abstract

This study examines the complex interplay of genetic and environmental interactions that shape chronic illness risk. Evidence is mounting for the role of genetic expression and the immune response in the pathogenesis of chronic disease. In the Rio Grande Valley of south Texas, where 90% of the population is Mexican American, chronic illnesses (including obesity, diabetes, nonalcoholic liver disease, and depression) are reaching epidemic proportions. This study leverages an ongoing family study of the genetic determinants of risk for obesity, diabetes, hypertension, hyperlipidemia, and depression in a Mexican American population. Data collected included blood pressure, BMI, hepatic transaminases, HbA1c, depression (BDI-II), acculturation/marginalization (ARSMA-II), and liver health as assessed by elastography. Heritability and genotype-by-environment (G×E) interactions were analyzed, focusing on the marginalization/separation measure of the ARSMA-II. Significant heritabilities were found for traits such as HbA1c (h² = 0.52), marginalization (h² = 0.30), AST (h² = 0.25), ALT (h² = 0.41), and BMI (h² = 0.55). Genotype-by-environment interactions were significant for HbA1c, AST/ALT ratio, BDI-II, and CAP, indicating that genetic factors interact with marginalization to influence these traits. This study found that acculturation stress exacerbates the genetic response to chronic illness. These findings underscore the importance of considering G×E interactions in understanding disease susceptibility and may inform targeted interventions for at-risk populations. Further research is warranted to elucidate the underlying molecular pathways and replicate these findings in diverse populations.

Keywords: G×E; Mexican Americans; NAFLD; acculturation stress; marginalization.

Figure 1

(a) The additive genetic variance function AST/ALT, BDI-II, BMI, CAP; (b) the residual environmental variance function for AST/ALT, BDI-II, CAP; (c) the genetic correlation function for A1C and AST/ALT.

Figure 1

(a) The additive genetic variance function AST/ALT, BDI-II, BMI, CAP; (b) the residual environmental variance function for AST/ALT, BDI-II, CAP; (c) the genetic correlation function for A1C and AST/ALT.

Figure 1

(a) The additive genetic variance function AST/ALT, BDI-II, BMI, CAP; (b) the residual environmental variance function for AST/ALT, BDI-II, CAP; (c) the genetic correlation function for A1C and AST/ALT.