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Tobacco products, especially when smoked or used orally, have serious negative effects on human health.[1][2] Smoking and smokeless tobacco use are the single greatest causes of preventable death globally.[3] Half of tobacco users die from complications related to such use.[4][5] Current smokers are estimated to die an average of 10 years earlier than non-smokers.[6] The World Health Organization estimates that, in total, about 8 million people die from tobacco-related causes, including 1.3 million non-smokers due to secondhand smoke.[7] It is further estimated to have caused 100 million deaths in the 20th century.[4]
Tobacco smoke contains over 70 chemicals, known as carcinogens, that cause cancer.[4][8] It also contains nicotine, a highly addictive psychoactive drug. When tobacco is smoked, the nicotine causes physical and psychological dependency. Cigarettes sold in least developed countries have higher tar content and are less likely to be filtered, increasing vulnerability to tobacco smoking–related diseases in these regions.[9]
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, known as secondhand smoke, has manifested harmful health effects in people of all ages.[10] Tobacco use is also a significant risk factor in miscarriages among pregnant smokers. It contributes to a number of other health problems for the fetus, such as premature birth and low birth weight, and increases the chance of sudden infant death syndrome (SIDS) by 1.4 to 3 times.[11] The incidence of erectile dysfunction is approximately 85 percent higher in male smokers compared to non-smokers.[12][13]
Many countries have taken measures to control the consumption of tobacco by restricting its usage and sales. 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 secondhand 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.[14] In the 1880s, automation dramatically reduced the cost of cigarettes, cigarette companies greatly increased their marketing, and use expanded.[15][16] 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 that tobacco users lived substantially shorter lives.[17][18] Further studies were published in Nazi Germany in 1939 and 1943, and one in the Netherlands in 1948. However, widespread attention was first drawn in 1950 by researchers from the United States and the United Kingdom, but their research was 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.[14] These results were accepted in the medical community and publicized among the general public in the mid-1960s.[14]
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