Coronavirus disease 2019 (COVID-19) has become a major health burden worldwide, with over 600 million confirmed cases and 6 million deaths by 15 December 2022. Although the acute phase of COVID-19 management has been established, the long-term clinical course and complications due to the relatively short outbreak is yet to be assessed. The current COVID-19 pandemic is causing significant morbidity and mortality around the world. Interestingly, epidemiological studies have shown that fatality rates vary considerably across different countries, and men and elderly patients are at higher risk of developing severe diseases. There is increasing evidence that COVID-19 infection causes neurological deficits in a substantial proportion to patients suffering from acute respiratory distress syndrome. Furthermore, lack of physical activity and smoking are associated with severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) susceptibility. We should therefore explore why lack of physical activity, smoking, etc causing a population more susceptible to SARS-CoV-2 infection, and mechanism involved. Thus, in this review article, we summarize epidemiological evidence related to risk factors and lifestyle that affect COVID-19 severity and the mechanism involved. These risk factors or lifestyle interventions include smoking, cardiovascular health, obesity, exercise, environmental pollution, psychosocial social stress, and diet.

Introduction: Age-related macular degeneration (ARMD) is an ocular degenerative disorder that associated with impairment of central vision. Oxidative stress plays an important role in the pathogenesis of ARMD. The aim of this study was to determine the level of antioxidant enzymes (catalase and glutathione peroxidase) in tears among Malay ARMD patients. Methods: A cross sectional study was conducted between September 2015 and November 2017 among Malay ARMD patients. Schirmer paper was used to collect the tear samples. The level of catalase and glutathione peroxidase level in tears was evaluated using commercially available oxidative stress marker kits. Results: A total of 136 Malay ARMD patients were recruited into the study with 68 controls. Mean tear catalase and glutathione peroxidase levels were significantly lower in ARMD patients (1348.97 SD 109.11 µM and 453.87 SD 41.96 U/L respectively) as compared to the control group (1453.38 SD 38.87 µM and 502.28 SD 34.29 U/L respectively) (P<0.001 and P<0.001 respectively). Late ARMD has lower mean of catalase level in tears as compared to early ARMD (P=0.044). Based on subtypes of neovascular late ARMD, neovascular ARMD has lower mean catalase level in tears compared to idiopathic polypoidal choroidal vasculopathy (IPCV) (P=0.031). Conclusion: This study showed that antioxidant enzyme might play an important factor in the pathogenesis of ARMD.