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Health effects of tobacco

 

Health effects of tobacco are the effects that use of tobacco has on human health, and concern about health effects of tobacco has a long history. Research has focused primarily on cigarette tobacco smoking. In 1950, Richard Doll published research in the British Medical Journal showing a close link between smoking and lung cancer. Four years later, in 1954, the British Doctors Study, a study of some 40,000 doctors over 20 years, confirmed the suggestion, based on which the government issued advice that smoking and lung cancer rates were related.

Tobacco use 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 600,000 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 of sudden 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 as warning 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 countries tend to have higher tar content, and are less likely to be filtered, potentially increasing vulnerability to tobacco smoking related disease in these regions.

Health effects of smoking

 

Addiction experts in psychiatry, chemistry, pharmacology, forensic science, epidemiology, and the police and legal services engaged in delphic analysis regarding 20 popular recreational drugs. Tobacco was ranked 3rd in dependence, 14th in physical harm, and 12th in social harm.

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 the amount of tobacco smoked, with those who smoke more at greater risk. Smoking so-called "light" cigarettes does not reduce the risk.

Mortality

 

Smoking is the cause of about 5 million deaths per year. This makes it the most common cause of preventable early death. One study found that male and female smokers lose on average of 13.2 and 14.5 years of life, respectively. Another found a loss of life of 6.8 years. Each cigarette that is smoked is estimated to shorten life by an average of 11 minutes. 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 as 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 and stomach cancer. Studies have established a relationship between tobacco smoke, including secondhand smoke, and cervical 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

 

Since establishing causation through experimental trials was not possible due to ethical restrictions, a lengthy study was conducted in order to establish the strong association necessary to allow for legislative action against tobacco consumption.

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 characterized 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

Smoking can cause atherosclerosis leading to coronary artery disease and peripheral arterial disease