Effects of smoking
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Effects of Smoking: A Comprehensive Overview
Respiratory Health Risks of Smoking
Increased Risk of Lung Cancer, COPD, and Asthma
Smoking significantly elevates the risk of several respiratory diseases. Among adult smokers, the risk of lung cancer is dramatically higher, with a risk ratio (RR) of 10.92. Chronic Obstructive Pulmonary Disease (COPD) also shows a substantial increase in risk (RR, 4.01). Additionally, smoking is linked to a higher incidence of asthma (RR, 1.61). Passive smoke exposure further exacerbates these risks, particularly in children, leading to increased asthma, wheeze, lower respiratory infections, and reduced lung function.
Impact on Asthma Management
For asthmatics, smoking and secondhand smoke (SHS) exposure result in poorer disease control and reduced effectiveness of inhaled corticosteroids. Maternal exposure to SHS is particularly detrimental, increasing the frequency and severity of asthma in children and reducing lung function. This exposure also leads to increased school absences due to respiratory illnesses.
Cognitive and Neurological Effects
Cognitive Decline and Brain Health
Exposure to tobacco smoke is associated with negative cognitive outcomes, including preclinical brain changes such as silent brain infarcts, white matter hyperintensities, and atrophy. Smoking is linked to cognitive decline and an increased risk of dementia, with potential mechanisms including oxidative stress, inflammation, and atherosclerotic processes. While nicotine has some short-term cognitive benefits, it may also pose risks, particularly for neurodevelopment in children and in catalyzing neuropathological processes in Alzheimer's Disease.
Systemic Health Impacts
Cardiovascular Disease
Smoking is a major risk factor for cardiovascular disease (CVD), contributing to conditions such as heart failure, atrial fibrillation, and venous thromboembolism. The adverse effects of smoking on the cardiovascular system are extensive and persistent, even with the use of alternative tobacco delivery systems like heat-not-burn products.
Inflammatory and Coagulation Pathways
Long-term smoking leads to systemic oxidative stress and a low-grade inflammatory response, evidenced by elevated levels of C-reactive protein (CRP), fibrinogen, and interleukin-6. These inflammatory markers remain elevated even years after smoking cessation, indicating a prolonged impact on the body's inflammatory state. Additionally, smoking alters coagulation and endothelial function, increasing the risk of thrombotic events.
Infectious Diseases
Increased Susceptibility and Severity
Smoking increases the risk of various infections, including respiratory, digestive, and reproductive tract infections. It is a significant risk factor for diseases such as HIV, tuberculosis, and SARS-CoV-2, with smoking cessation being a crucial preventive measure. The mechanisms behind this increased susceptibility include alterations in structural, functional, and immunologic host defenses.
Conclusion
Smoking has far-reaching and severe health effects, impacting respiratory, cognitive, cardiovascular, and immune systems. The increased risks of lung cancer, COPD, asthma, cognitive decline, cardiovascular diseases, and infections highlight the critical need for smoking cessation and preventive measures. Despite some reversible effects post-cessation, the long-term health impacts underscore the importance of early intervention and sustained efforts to reduce smoking prevalence globally.
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