Mediation Effect of JAK2 Methylation on the Association Between Sitting Time and Abdominal Obesity in Rural Adults.

Background Sitting time may affect health by altering the methylation of certain genes. This research aimed to estimate the association of sitting time with abdominal obesity and the role of Janus kinase 2 (JAK2) methylation in the association among rural adults. Methods A total of 1062 rural adults from the Henan Rural Cohort Study were included. Whole blood was used to extract genomic DNA. JAK2 DNA methylation level was assessed by MethylTarget TM . The logistic regression model was utilized to assess the association of sitting time with abdominal obesity, and the possible effect of JAK2 DNA methylation on the association were conducted by using mediation analyses. Results Average time of sitting of participants was 7.28 ± 3.37 h/d. For per 1 h increment in sitting time, the odd ratio ( OR ) and 95% confidence interval ( CI ) of abdominal obesity was 1.153 (1.095, 1.214) after controlling potential risk factors. Simultaneously, the methylation levels of Chr9: 4985407 site and Chr9: 4985238-4985455 region were negatively correlated with abdominal obesity ( OR : 0.549, 95% CI : 0.394, 0.765; OR : 0.189, 95% CI : 0.056, 0.640, respectively). Moreover, Chr9: 4985407 site and Chr9: 4985238-4985455 region methylation levels mediated the association of sitting time with abdominal obesity, and the indirect effects account for 6.78% and 4.24%, respectively. Conclusions Longer sitting time was positively correlated with abdominal obesity in the rural population, and methylation level of JAK2 may be an underlying mediation of the effect.