Tobacco Smoking as an EDC in Metabolic Disorders

Tobacco smoking is a leading concern to a global health; kills almost six million individuals annually and associated with life-threating health issues. Nearly 80% smokers live in middle- and low-income countries where illness and mortality rate due to cigarette smoking are higher. Tobacco smoking is interlinked with a numerous disease, comprising lungs cancer, chronic obstructive pulmonary disease, infertility, cardiovascular events, stroke, and metabolic disorders. Tobacco smoking has ability to obstruct and/or interfere in the function of endocrine system; has been entitled as endocrine disrupting chemicals (EDCs). EDCs are a heterogeneous group of exogenous compounds that can restrict with several facets of endogenous hormones. Standard role of endocrine system is reliant on hormonal/enzymatic pathway which may act as chemical and biological messengers to regulate the physiological functions of an organism. Tobacco smoking is also responsible to impair the regular metabolic pathway through interaction with members of superfamily of nuclear receptor such as peroxisome proliferator activated receptor, thyroid hormone receptors, liver X receptor, and retinoid X receptor. Smoking can also affect the multiple pathways including inflammatory response, DNA damaging, and oxidative stress. Reactive oxygen species (ROS) work as a second messenger in miscellaneous mitochondrial and cellular procedures and signaling pathways. On the other hand, excessive ROS might react with nucleic acid, lipids, carbohydrates, and protein causing inflammation and oxidative stress that are the main causes for the development of various metabolic disorders. Hence, this chapter will include the detailed discussion about the impact of cigarette smoking on metabolic disorder along with its effects on several enzymatic and metabolic pathways.