A male preponderance of cancer occurrence and combination of all the three habits (smoking, alcohol, and chewing) were found to be the significant risk factors. Males were more likely to be diagnosed later than females.

To understand whether oxidants contribute to the initiation and/or promulgation toward aging, the present study has been undertaken on 220 healthy male volunteers aged 20-80 years selected from the defined electoral area (suburbs of Tirupati, Andhra Pradesh, India) to evaluate the concentrations of free radicals (superoxide anion, hydrogen peroxide), lymphocyte antioxidant enzymes (glutathione S-transferase, superoxide dismutase, catalase), and DNA damage in relation to obesity and smoking (lifestyles). A two fold increase of lymphocyte free radical generation (DNA damage) was observed in older age groups with a reduced antioxidant potential, forming a link between cigarette smoking and oxidative stress represented by an antioxidant imbalance. Body mass index had a positive relationship with oxidative stress, but antioxidant levels did not vary with body mass index. The findings conclude that free radical-mediated oxidative stress and DNA damage accelerate with lifestyle variations under reduced antioxidant potential.

Acute necrotizing encephalopathy (ANE) is influenza-associated encephalopathy (IAE) that mostly occurs in younger age groups following an acute viral illness with a very low recovery rate. It is a rare but rapidly progressive neurodegenerative disorder which pathogenesis is still not clear. There are some cases reported where the virus can directly invade the central nervous system (CNS) through the peripheral nervous system. Several pathogenic conditions like rising levels of proinflammatory cytokines, dissolving the blood-brain barrier (BBB), etc can trigger the viral infection. There are no specific treatments available but initial steroid therapy in combination with antivirals and hypothermia therapy were found efficacious in some cases. Similarly, coronavirus disease 2019 (COVID-19) encephalopathy is caused by a novel coronavirus SARS-CoV-2 (severe acute respiratory syndrome coronavirus-2). Having a very low recovery rate, and still unknown pathophysiology, this condition is proved to be fatal for immunocompetent adults. Treatments are not available but drugs like remdesivir, hydroxychloroquine, tocilizumab, and losartan were used to reduce the viral infection. No recurrent cases have been reported so far, but reinfection of the virus can trigger hypoxic encephalopathy. This review mainly focuses on a comparative study to understand the pathophysiology to help for discovering a new area of drug development.