Exploring the Genetic Association between Obesity and Serum Lipid Levels Using Bivariate Methods

Area of Science:

• Genetics
• Metabolic Health
• Biostatistics

Background:

• Obesity and serum lipid levels are complex traits influenced by genetic and environmental factors.
• Understanding the genetic interplay between body mass index (BMI) and lipid profiles is crucial for public health.
• Previous studies suggest a genetic link, but specific genes and pathways require further elucidation.

Purpose of the Study:

• To investigate the heritability of BMI and serum lipid levels (total cholesterol, triglycerides, HDL-C, LDL-C) in a Chinese twin cohort.
• To determine the genetic correlations between BMI and lipid profiles.
• To identify genetic variants and biological pathways associated with both BMI and lipid levels.

Main Methods:

• Structural equation modeling (SEM) was used to estimate heritability and genetic correlations in 1197 twin pairs.
• Bivariate genome-wide association studies (GWAS) were conducted in 457 individuals and validated in 289 individuals.
• Pathway analysis was performed on identified genetic associations.

Main Results:

• Heritability estimates for BMI differed by gender (males: 71%, females: 39%).
• BMI showed positive phenotypic and genetic correlations with total cholesterol, triglycerides, and LDL-C, and a negative correlation with HDL-C.
• Bivariate GWAS identified 7 genes (e.g., MIR144) associated with BMI and lipid levels, implicating pathways in cholesterol reverse transport and HDL particle clearance.

Conclusions:

• BMI and serum lipid levels are significantly influenced by genetic factors and are genetically correlated.
• Gender-specific genetic correlations between BMI and lipids may exist.
• The MIR144 gene and associated biological pathways are potential contributors to the relationship between obesity and lipid metabolism.