The Association Between DNA Methylation of CASZ1 Gene and Overweight/obesity in the Chinese Han Population

Objective: The aim of this study was to examine the potential association between castor zinc finger 1 ( CASZ1 ) gene methylation and overweight/obesity, and investigate the interaction effects between CASZ1 methylation levels and some environmental factors on overweight/obesity. Methods: This study included 1,029 individuals. The methylation levels of CpG sites at CASZ1 promoter were measured with bisulfite sequencing method. Multiple linear regression and logistic regression models were used to analyze the association between CASZ1 methylation and body mass index (BMI) and overweight/obesity, respectively; while additive scale and multiplicative scale were used to evaluate the interaction effects between methylation levels and environmental factors on overweight/obesity. Results: The levels of CASZ1 methylation at CpG51, 70, 72, 98, 157, 165 were associated with BMI after adjustments. There were differences between cases and controls in the levels of DNA methylation at CpG58, 72, 98, 116, 157, 163, 165. Methylations at CpG72, 98, 163, 165 were associated with overweight/obesity after adjustments. The association between methylation levels of CpG98 (Odds ratio=1.06, 95%Confidence interval: 1.02-1.10) and CpG165 (Odds ratio =1.15, 95% Confidence interval: 1.07-1.42) and overweight/obesity was significant after considering multiple testing ( P < 0.003). Besides, we found significant additive interaction effects of drinking status and triglyceride level with CpG163 on BMI. Conclusion: The methylation levels of CpG sites in CASZ1 gene, as well as the interactions with some environmental factors, were associated with overweight/obesity in the Chinese Han population.