an important cause of premature death worldwide." Although 70% of smokers state their intention to quit only 3–5% are actually successful in doing so. The probabilities of death from lung cancer before age 75 in the United Kingdom are 0.2% for men who never smoked (0.4% for women), 5.5% for male former smokers (2.6% in women), 15.9% for current male smokers (9.5% for women) and 24.4% for male "heavy smokers" defined as smoking more than 5 cigarettes per day (18.5% for women). Tobacco smoke can combine with other carcinogens present within the environment in order to produce elevated degrees of lung cancer. The risk of lung cancer decreases almost from the first day someone quits smoking. Healthy cells that have escaped mutations grow and replace the damaged ones in the lungs. In the research dated December 2019, 40% of cells in former smokers looked like those of people who had never smoked. Rates of smoking have generally leveled-off or declined in the developed world. Smoking rates in the United States have dropped by half from 1965 to 2006, falling from 42% to 20.8% in adults. In the developing world, tobacco consumption is rising by 3.4% per year. Smoking alters the transcriptome of the lung parenchyma; the expression levels of a panel of seven genes (KMO, CD1A, SPINK5, TREM2, CYBB, DNASE2B, FGG) are increased in the lung tissue of smokers. Passive smoking is the inhalation of tobacco smoke by individuals who are not actively smoking. This smoke is known as second-hand smoke (SHS) or environmental tobacco smoke (ETS) when the burning end is present, and third-hand smoke after the burning end has been extinguished. Because of its negative implications, exposure to SHS has played a central role in the regulation of tobacco products. Six hundred thousand deaths were attributed to SHS in 2004. It also has been known to produce skin conditions such as freckles and dryness. In 2015, a meta-analysis found that smokers were at greater risk of developing psychotic disorder. Tobacco has also been described an anaphrodisiac due to its propensity for causing erectile dysfunction. There is a correlation between tobacco smoking and a reduced risk of Parkinson's disease. Economic In countries where there is a universally funded healthcare system, the government covers the cost of medical care for smokers who become ill through smoking in the form of increased taxes. Two broad debating positions exist on this front,