Health effects of tobacco
Tobacco products, especially when smoked or used orally, have serious negative effects on human health.[1][2] Smoking and smokeless tobacco use is the single greatest cause of preventable death globally.[3] As many as half of people who smoke tobacco or use it orally die from complications related to such use.[4] It has been estimated that each year, in total about 6 million people die from tobacco-related causes (about 10% of all deaths), with 600,000 of these occurring in non-smokers due to secondhand smoke.[4][5] It is further estimated to have caused 100 million deaths in the 20th century.[4]
"Health effects of smoking" and "Dangers of smoking" redirect here. For cannabis, see Effects of cannabis. For smoking crack cocaine, see Crack cocaine § Health issues.
Tobacco smoke contains over 70 chemicals that cause cancer.[4][6] It also contains nicotine, a highly addictive psychoactive drug. When tobacco is smoked, the nicotine in it causes physical and psychological dependency. Cigarettes sold in underdeveloped countries have higher tar content. They are less likely to be filtered, increasing vulnerability to tobacco smoking–related diseases in these regions.[7]
Tobacco use most commonly leads to diseases affecting the heart, liver and lungs. Smoking is a major risk factor for several conditions, namely pneumonia, heart attacks, strokes, chronic obstructive pulmonary disease (COPD) (including emphysema and chronic bronchitis), and multiple cancers (particularly lung cancer, cancers of the larynx and mouth, bladder cancer, and pancreatic cancer). It is also responsible for peripheral arterial disease and high blood pressure. The effects vary, depending on how frequently and for how many years a person smokes. Smoking earlier in life and smoking cigarettes higher in tar increase the risk of these diseases. Additionally, environmental tobacco smoke, or second-hand smoke, has manifested harmful health effects in people of all ages.[8] Tobacco use is also a significant factor in miscarriages among pregnant smokers. It contributes to a number of other health problems of the fetus such as premature birth, low birth weight, and increases the chance of sudden infant death syndrome (SIDS) by 1.4 to 3 times.[9] Incidence of erectile dysfunction is approximately 85 percent higher in male smokers compared to non-smokers.[10][11]
Many countries have taken measures to control the consumption of tobacco (smoking) by restricting its usage and sales. On top of that, they have printed warning messages on packaging. Moreover, smoke-free laws that ban smoking in public places like workplaces, theaters, bars, and restaurants have been enacted to reduce exposure to second-hand smoke.[4] Tobacco taxes inflating the price of tobacco products have also been imposed.[4]
In the late 1700s and the 1800s, the idea that tobacco use caused certain diseases, including mouth cancers, was initially accepted by the medical community.[12] In the 1880s, automation dramatically reduced the cost of cigarettes, cigarette companies greatly increased their marketing, and use expanded.[13][14] From the 1890s onwards, associations of tobacco use with cancers and vascular disease were regularly reported. By the 1930s multiple researchers concluded that tobacco use caused cancer and tobacco users lived substantially shorter lives.[15][16] Further studies were published in Nazi Germany in 1939 and 1943, and one in the Netherlands in 1948. However, the widespread attention was first drawn in 1950 by researchers from the US and UK but their research were widely criticized. Follow-up studies in the early 1950s found that smokers died faster and were more likely to die of lung cancer and cardiovascular disease.[12] These results were accepted in the medical community and publicized among the general public in the mid-1960s.[12]
Education and counselling by physicians of children and adolescents have been found to be effective in decreasing tobacco use.[281] The World Health Organization (WHO) estimates that 5.6 billion people, or 71% of the world's population, are protected by at least one tobacco prevention policy.[282]
History[edit]
Pre-cigarette[edit]
Texts on the harmful effects of smoking tobacco were recorded in the Timbuktu manuscripts.[302]
James I wrote a book that denounced tobacco smoking as: "...loathsome to the eye, hateful to the nose, harmful to the brain, dangerous to the lungs..."[303]
Pipe smoking gradually became generally accepted as a cause of mouth cancers following work done in the 1700s. "An association between a variety of cancers and tobacco use was repeatedly observed from the late 1800s into the early 1920s."[304]
Gideon Lincecum, an American naturalist and practitioner of botanical medicine, wrote in the early 19th century on tobacco: "This poisonous plant has been used a great deal as a medicine by the old school faculty, and thousands have been slain by it. ... It is a very dangerous article, and use it as you will, it always diminishes the vital energies in exact proportion to the quantity used – it may be slowly, but it is very sure."[305]
The 1880s invention of automated cigarette-making machinery in the American South made it possible to mass-produce cigarettes at low cost, and smoking became common. This led to a backlash and a tobacco prohibition movement, which challenged tobacco use as harmful and brought about some bans on tobacco sale and use.[13] In 1912, American Dr. Isaac Adler was the first to strongly suggest that lung cancer is related to smoking.[306] In 1924, economist Irving Fisher wrote an anti-smoking article for Reader's Digest which said "...tobacco lowers the whole tone of the body and decreases its vital power and resistance ... tobacco acts like a narcotic poison, like opium, and like alcohol, though usually in a less degree".[307] In December 1952, the Reader's Digest reprinted an article titled Cancer by the Carton which outlined the research links between smoking and lung cancer.
Prior to World War I, lung cancer was considered to be a rare disease, which most physicians would never see during their career.[308][309] With the postwar rise in popularity of cigarette smoking, however, came an epidemic of lung cancer.[310][311] For instance, it is estimated that "35 to 79 percent of excess veteran deaths due to heart disease and lung cancer are attributable to military-induced smoking"[312]
Early observational studies[edit]
From the 1890s onwards, associations of tobacco use with cancers and vascular disease were regularly reported.[12] In 1930, Fritz Lickint of Dresden, Germany, published[16][15] a meta-analysis citing 167 other works to link tobacco use to lung cancer.[15] Lickint showed that people with lung cancer were likely to be smokers. He also argued that smoking tobacco was the best way to explain the fact that lung cancer struck men four or five times more often than women (since women smoked much less),[16] and discussed the causal effect of smoking on cancers of the liver and bladder.[15]