a day results in a risk of coronary heart disease that is halfway between that of a heavy smoker and a non-smoker. The non-linear dose–response relationship may be explained by smoking's effect on platelet aggregation. Among the diseases that can be caused by smoking are vascular stenosis, lung cancer, heart attacks and chronic obstructive pulmonary disease (COPD). Smoking during pregnancy may cause ADHD to a fetus. Smoking is a risk factor strongly associated with periodontitis and tooth loss. The effects of smoking on periodontal tissues depend on the number of cigarettes smoked daily and the duration of the habit. A study showed that smokers had 2.7 times and former smokers 2.3 times greater probabilities to have established periodontal disease than non‐smokers, independent of age, sex and plaque index, however, the effect of tobacco on periodontal tissues seems to be more pronounced in men than in women. Studies have found that smokers had greater odds for more severe dental bone loss compared to non‐smokers , also, people who smoke and drink alcohol heavily have much higher risk of developing oral cancer (mouth and lip) compared with people who do neither. Smoking can also cause milanosis in the mouth. Smoking has been also associated with oral conditions including dental caries, dental implant failures, premalignant lesions, and cancer. Smoking can affect the immune-inflammatory processes which may increase the susceptibility to infections; it can alter the oral mycobiota and facilitate colonization of the oral cavity with fungi and pathogenic molds. Many governments are trying to deter people from smoking with anti-smoking campaigns in mass media stressing the harmful long-term effects of smoking. Passive smoking, or secondhand smoking, which affects people in the immediate vicinity of smokers, is a major reason for the enforcement of smoking bans. These are laws enforced to stop individuals from smoking in indoor public places, such as bars, pubs and restaurants, thus reducing nonsmokers' exposure to secondhand smoke. A common concern among legislators is to discourage smoking among minors and many states have passed laws against selling tobacco products to underage customers (establishing a smoking age). Many developing countries have not adopted anti-smoking policies, leading some to call for anti-smoking campaigns and further education to explain the negative effects of ETS (Environmental Tobacco Smoke) in developing countries. Tobacco advertising is also sometimes regulated to make smoking less appealing. Despite the many bans, European countries still hold 18 of the top