[Relationship of telomere length, mitochondrial DNA copy number of peripheral blood with hypertension in coal miners].

Objective: To explore the relationship of telomere length, mitochondrial DNA copy number of peripheral blood with hypertension and the interaction between telomere length and mtDNA-CN on hypertension in coal miners. Methods: A case control study was conducted in a coal mine of Shanxi province from July to December of 2013, in which 325 healthy workers were selected as the control group and 378 workers with hypertension as the case group. The information about general demographic characteristics and life behavior habits of the subjects were collected through questionnaire. Levels of telomere length and mtDNA-CN in peripheral blood were detected by real-time PCR. Unconditional logistic regression was used to examine the association between hypertension and telomere length, mtDNA-CN. The interaction test between telomere length and mtDNA-CN on hypertension was performed by adding the interaction term in the corresponding model. Results: The mean telomere length of the workers in the case group was (1.50±0.55) kb, and that of the control group was (2.01±0.62) kb, the difference between two groups was significant ( t =11.68, P <0.001). The correlation analysis showed that telomere length was positively correlated with mtDNA-CN ( r =0.157, P =0.002) in the case group. Multivariate analysis showed that telomere length ( OR =4.408, 95% CI : 3.012-6.452), age ( OR =0.417, 95% CI : 0.284-0.613), BMI ( OR =1.357, 95% CI : 1.162-1.584), monthly household income level ( OR =0.656, 95% CI : 0.553-0.778) and work duration ( OR =1.249, 95% CI : 1.100-1.417) were influencing factors of hypertension. The multiply interaction between telomere length and mtDNA-CN was significant on hypertension ( OR =1.267, 95% CI : 1.094-1.468). Conclusions: The results suggest shorter telomere length is a risk factor of hypertension. There is a multiply interaction between telomere length and mtDNA-CN on hypertension. However, the association between mtDNA-CN and hypertension was not found.