Health effects of tobacco
"Health effects of smoking" redirects here. For cannabis, seeEffects of cannabis § Smoked. For smoking crack cocaine, seeCrack cocaine § Health issues.
The health effects of tobacco are the affects that use of tobaccohas on human health. Research has focused primarily on cigarettetobacco smoking.
Tobacco is the single greatest cause of preventable death globally As many as half of people who use tobacco die from the results of this use. The World Health Organization (WHO) estimates that each year tobacco causes about 6 million deaths (about 10% of all deaths) with 0.6 million of these occurring in non smokers due to second hand smoke. In the 20th century tobacco is estimated to have caused 100 million deaths. Similarly, the United States Centers for Disease Control and Prevention describes tobacco use as "the single most important preventable risk to human health in developed countries and an important cause of premature death worldwide."
Tobacco use leads most commonly to diseases affecting the heart, liver and lungs. Smoking is a major risk factor for heart attacks, strokes, chronic obstructive pulmonary disease (COPD) (including emphysema and chronic bronchitis), and cancer(particularly lung cancer, cancers of the larynx and mouth, and pancreatic cancer). It also causes peripheral vascular disease and hypertension. The effects depend on the number of years that a person smokes and on how much the person smokes. Starting smoking earlier in life and smoking cigarettes higher in tar increases the risk of these diseases. Also, environmental tobacco smoke, or secondhand smoke, has been shown to cause adverse health effects in people of all ages. Tobacco use is a significant factor in miscarriages among pregnant smokers, and it contributes to a number of other health problems of the fetus such as premature birth, low birth weight, and increases by 1.4 to 3 times the chance ofsudden infant death syndrome (SIDS).Incidence of erectile dysfunction is approximately 85 percent higher in male smokers compared to non-smokers.
Several countries have taken measures to control the consumption of tobacco with usage and sales restrictions as well aswarning messages printed on packaging. Additionally smoke free laws are useful, do not have negative economic effects for restaurants or bars and help people who smoke to quit. Taxing tobacco products in an effort to increase the price is also effective, especially in developing countries. Tobacco smoke contains more than fifty chemicals that cause cancer.Tobacco also contains nicotine, which is a highly addictive psychoactive drug. When tobacco is smoked, nicotine causes physical and psychological dependency. Cigarettes sold in underdeveloped coutries tend to have higher tar content, and are less likely to be filtered, potentially increasing vulnerability to tobacco smoking related disease in these regions.
| Part of a series on |
| Tobacco |
|---|
 |
| HISTORY |
|
| BIOLOGY |
|
| PERSONAL AND SOCIAL IMPACT |
|
| PRODUCTION |
|
Health effects of smoking
Smoking most commonly leads to diseases affecting the heart and lungs and will most commonly affect areas such as hands or feet with first signs of smoking related health issues showing up as numbness, with smoking being a major risk factor for heart attacks, Chronic Obstructive Pulmonary Disease (COPD), emphysema, and cancer, particularly lung cancer, cancers of the larynx and mouth, and pancreatic cancer. Overall life expectancy is also reduced in long term smokers, with estimates ranging from 10 to 17.9. years fewer than nonsmokers. About one half of long term male smokers will die of illness due to smoking. The association of smoking with lung cancer is strongest, both in the public perception and etiologically. Among male smokers, the lifetime risk of developing lung cancer is 17.2%; among female smokers, the risk is 11.6%. This risk is significantly lower in nonsmokers: 1.3% in men and 1.4% in women. Historically, lung cancer was considered to be a rare disease prior to World War I and was perceived as something most physicians would never see during their career. With the postwar rise in popularity of cigarette smoking came a virtual epidemic of lung cancer.
A person's increased risk of contracting disease is directly proportional to the length of time that a person continues to smoke as well as the amount smoked. However, if someone stops smoking, then these chances gradually decrease as the damage to their body is repaired. A year after quitting, the risk of contracting heart disease is half that of a continuing smoker. The health risks of smoking are not uniform across all smokers. Risks vary according to amount of tobacco smoked, with those who smoke more at greater risk. Smoking so-called "light" cigarettes does not reduce the risk.
Mortality
Male and female smokers lose an average of 13.2 and 14.5 years of life, respectively. Each cigarette that is smoked is estimated to shorten life by an average of 11 minutes. According to the results of a 50-year study of 34,486 male British doctors, at least half of all lifelong smokers die earlier as a result of smoking. Smokers are three times as likely to die before the age of 60 or 70 unlike non-smokers.
In the United States, cigarette smoking and exposure to tobacco smoke accounts for roughly one in five, or at least 443,000 premature deaths annually. To put this into context, ABC's Peter Jennings famously reported that in the US alone, tobacco kills the equivalent of three jumbo jets full of people crashing every day, with no survivors. On a worldwide basis, this equates to a single jumbo jet every hour.
A 2015 study found that about 17% of mortality due to cigarette smoking in the United States is due to diseases other than those usually believed to be related.
Cancer
The primary risks of tobacco usage include many forms of cancer, particularly lung cancer, kidney cancer, cancer of the larynx and head and neck, bladder cancer, cancer of the esophagus, cancer of the pancreas andstomach cancer. Studies have established a relationship between tobacco smoke, including secondhand smoke, andcervical cancer in women. There is some evidence suggesting a small increased risk of myeloid leukaemia, squamous cell sinonasal cancer, liver cancer, colorectal cancer, cancers of the gallbladder, the adrenal gland, the small intestine, and various childhood cancers. The possible connection between breast cancer and tobacco is still uncertain.
The risk of dying from lung cancer before age 85 is 22.1% for a male smoker and 11.9% for a female smoker, in the absence of competing causes of death. The corresponding estimates for lifelong nonsmokers are a 1.1% probability of dying from lung cancer before age 85 for a man of European descent, and a 0.8% probability for a woman.
Pulmonary
In smoking, long term exposure to compounds found in the smoke (e.g., carbon monoxide and cyanide) are believed to be responsible for pulmonary damage and for loss of elasticity in the alveoli, leading to emphysema and COPD. Chronic obstructive pulmonary disease (COPD) caused by smoking, is a permanent, incurable (often terminal) reduction of pulmonary capacity characterised by shortness of breath, wheezing, persistent cough with sputum, and damage to the lungs, including emphysema and chronic bronchitis. The carcinogen acrolein and its derivatives also contribute to the chronic inflammation present in COPD.
Cardiovascular disease
Inhalation of tobacco smoke causes several immediate responses within the heart and blood vessels. Within one minute the heart rate begins to rise, increasing by as much as 30 percent during the first 10 minutes of smoking. Carbon monoxide in tobacco smoke exerts its negative effects by reducing the blood’s ability to carry oxygen. Both of these conditions can become permanent with prolonged use of cigarettes.
Smoking also increases the chance of heart disease, stroke, atherosclerosis, andperipheral vascular disease. Several ingredients of tobacco lead to the narrowing of blood vessels, increasing the likelihood of a blockage, and thus a heart attack orstroke. According to a study by an international team of researchers, people under 40 are five times more likely to have a heart attack if they smoke.
Recent research by American biologists has shown that cigarette smoke also influences the process of cell division in the cardiac muscle and changes the heart's shape.
The usage of tobacco has also been linked to Buerger's disease (thromboangiitis obliterans) the acute inflammation and thrombosis (clotting) of arteries and veins of the hands and feet.
Although cigarette smoking causes a greater increase of the risk of cancer than cigar smoking, cigar smokers still have an increased risk for many health problems, including cancer, when compared to non-smokers. As for second-hand smoke, the NIH study points to the large amount of smoke generated by one cigar, saying "cigars can contribute substantial amounts of tobacco smoke to the indoor environment; and, when large numbers of cigar smokers congregate in a cigar smoking event, the amount of ETS [i.e. second-hand smoke] produced is sufficient to be a health concern for those regularly required to work in those environments."
Smoking tends to increase blood cholesterol levels. Furthermore, the ratio of high-density lipoprotein (the "good" cholesterol) to low-density lipoprotein (the "bad" cholesterol) tends to be lower in smokers compared to non-smokers. Smoking also raises the levels of fibrinogen and increases platelet production (both involved in blood clotting) which makes the blood viscous. Carbon monoxide binds to haemoglobin (the oxygen-carrying component in red blood cells), resulting in a much stabler complex than haemoglobin bound with oxygen or carbon dioxide—the result is permanent loss of blood cell functionality. Blood cells are naturally recycled after a certain period of time, allowing for the creation of new, functional erythrocytes. However, if carbon monoxide exposure reaches a certain point before they can be recycled, hypoxia (and later death) occurs. All these factors make smokers more at risk of developing various forms of arteriosclerosis. As the arteriosclerosis progresses, blood flows less easily through rigid and narrowed blood vessels, making the blood more likely to form a thrombosis (clot). Sudden blockage of a blood vessel may lead to an infarction (stroke). However, it is also worth noting that the effects of smoking on the heart may be more subtle. These conditions may develop gradually given the smoking-healing cycle (the human body heals itself between periods of smoking), and therefore a smoker may develop less significant disorders such as worsening or maintenance of unpleasant dermatological conditions, e.g. eczema, due to reduced blood supply. Smoking also increases blood pressure and weakens blood vessels.
Renal
In addition to increasing the risk of kidney cancer, smoking can also contribute to additional renal damage. Smokers are at a significantly increased risk for chronic kidney disease than non-smokers. A history of smoking encourages the progression of diabetic nephropathy.
Influenza
A study of an outbreak of A(H1N1) influenza in an Israeli military unit of 336 healthy young men to determine the relation of cigarette smoking to the incidence of clinically apparent influenza, revealed that, of 168 smokers, 68.5 percent had influenza, as compared with 47.2 percent of nonsmokers. Influenza was also more severe in the smokers; 50.6 percent of the smokers lost work days or required bed rest, or both, as compared with 30.1 percent of the nonsmokers.
According to a study of 1,900 male cadets after the 1968 Hong Kong A2 influenza epidemic at a South Carolina military academy, compared with nonsmokers, heavy smokers (more than 20 cigarettes per day) had 21% more illnesses and 20% more bed rest, light smokers (less than 20 cigarettes per day) had 10% more illnesses and 7% more bed rest.
The effect of cigarette smoking upon epidemic influenza was studied prospectively among 1,811 male college students. Clinical influenza incidence among those who daily smoked 21 or more cigarettes was 21% higher than that of non-smokers. Influenza incidence among smokers of 1 to 20 cigarettes daily was intermediate between non-smokers and heavy cigarette smokers.
Surveillance of a 1979 influenza outbreak at a military base for women in Israel revealed that influenza symptoms developed in 60.0% of the current smokers vs. 41.6% of the nonsmokers.
Smoking seems to cause a higher relative influenza-risk in older populations than in younger populations. In a prospective study of community-dwelling people 60–90 years of age, during 1993, of unimmunized people 23% of smokers had clinical influenza as compared with 6% of non-smokers.
Smoking may substantially contribute to the growth of influenza epidemics affecting the entire population. However the proportion of influenza cases in the general non-smoking population attributable to smokers has not yet been calculated.
Oral
Perhaps the most serious oral condition that can arise is that of oral cancer. However, smoking also increases the risk for various other oral diseases, some almost completely exclusive to tobacco users. The National Institutes of Health, through the National Cancer Institute, determined in 1998 that "cigar smoking causes a variety of cancers including cancers of theoral cavity (lip, tongue, mouth, throat), esophagus, larynx, and lung."Pipe smoking involves significant health risks,]particularly oral cancer. Roughly half of periodontitis or inflammation around the teeth cases are attributed to current or former smoking. Smokeless tobacco causes gingival recession and white mucosal lesions. Up to 90% of periodontitis patients who are not helped by common modes of treatment are smokers. Smokers have significantly greater loss of bone height than nonsmokers, and the trend can be extended to pipe smokers to have more bone loss than nonsmokers.Smoking has been proven to be an important factor in the staining of teeth. Halitosis or bad breath is common among tobacco smokers. Tooth loss has been shown to be 2 to 3 times higher in smokers than in non-smokers. In addition, complications may further include leukoplakia, the adherent white plaques or patches on the mucous membranes of the oral cavity, including the tongue.
Infection
Smoking is also linked to susceptibility to infectious diseases, particularly in the lungs. Smoking more than 20 cigarettes a day increases the risk of by two to four times, and being a current smoker has been linked to a fourfold increase in the risk of invasive pneumococcal disease. It is believed that smoking increases the risk of these and other pulmonary and respiratory tract infections both through structural damage and through effects on the immune system. The effects on the immune system include an increase in CD4+ cell production attributable to nicotine, which has tentatively been linked to increased HIV susceptibility.
Smoking increases the risk of Kaposi's sarcoma in people without HIV infection.One study found this only with the male population and could not draw any conclusions for the female participants in the study.
Impotence
Incidence of impotence is approximately 85 percent higher in male smokers compared to non-smokers, and it is a key cause of erectile dysfunction (ED). Smoking causes impotence because it promotes arterial narrowing.
No comments:
Post a Comment