Summary: Background: Mitochondrial DNA copy number (mtCN) maintains cellular function and homeostasis. and is linked to nuclear DNA methylation and gene expression. Increased mtCN in the blood is associated with smoking and respiratory disease. but has received little attention for target organ effects for smoking or electronic cigarette (EC) use. https://www.hollandscountryclothinges.shop/product-category/soft-top-socks/