Comparative effects of alternate tobacco products and traditional tobacco smoking on various organ/systems: A guide to regulators and health policy makers.

Traditional Tobacco smoking (TTS) is globally known as the single largest avoidable risk factor for a broad range of diseases. It is believed to be a "pandemic" because of its deleterious global impact on public health. Over a century ago, there has been a wide spread of tobacco cigarettes, originating particularly from the Americas; and most recently alternative tobacco products, such as heated tobacco products (HTPs), nicotine pouches, e-cigarettes, etc. This is due to the perceived safety of the latter. Data for this review were gotten through a rigorous search of scientific literatures on PubMed, Elsevier, Google scholar and Scopus. Unbiased findings on these search engines were included in this study, while claims that are unscientific were excluded. The deleterious health effects of e-cigarette aerosols (ECA) have been linked largely to the e-juice or e-liquid which majorly contains nicotine, flavorings, propylene glycol and other unregulated additives. In the respiratory system, TTS and ECA cause increase in pulmonary macrophage count and higher cell influx. However, TTS caused a higher lipid peroxidation judged by an increase in malondialdehyde (MDA) level. ECA caused a shift in the histo-architecture of the lungs, featuring an increase in volume density of the alveolar space which is associated with Chronic Obstructive Pulmonary Disease (COPD). Studies involving the cardiovascular system explored the e-liquid constituents such as nicotine, linked to atherosclerosis; cardiac tissue remodeling and cardiotoxic thermal metabolites of propylene glycol. On cardiac tissue remodeling, ECA caused significant increase in angiogenesis in mouse heart tissues, coupled with increase collagen production but not tissue fibrosis. This suggests that acute exposure to ECA did not adversely affect contractile functions or fibrosis. However, this was contrary with TTS, which showed inhibition of angiogenesis and induction of cardiac fibrosis. The increasing use of ECA amongst young adults showed more tendency for neurological defects when compared with TTS (since its consumption is reduced), this is mainly due to combinatory neurotoxic effects of nicotine, flavorings, formaldehyde, etc., causing a negative effect on cognition and attention span. Putting these together, further research needs to be carried out on long-term safety of e-cigarettes, while national health regulators and policy makers should provide informed policies on the use of e-cigarettes and other alternative tobacco products.