In the 1980s, the hazard of smoking has been widely recognized by general public in western countries. While, during the same period, China had developed rapidly as the world's leading tobacco production and consumption country. However, due to the delay of smoking consumption peak comparing with developed countries, the smoking related research in China had lagged behind western developed countries for nearly 50 years and basic epidemiological information regarding to the health problems associated with smoking was lacking. Therefore, it was imperative to undertake nationwide research to depict the hazards related with smoking comprehensively and systematically, which was crucial for forming preventive public health policy as well as raising awareness of health risk caused by cigarette smoking among general population in China. However, it is almost impossible to achieve this goal in a short period by directly applying traditional epidemiological research designs, such as cohort design and case-control design, both of which are most frequently used in epidemiological etiological studies. In cohort studies, subjects need to be followed up for a period of time to observe the occurrence of the events of interest, which usually takes a long time for a cohort study to mature. While for case-control studies require control group to be an approximate random sample of base population, which is hardly to meet in large-scale population studies. Therefore, there was a call for methodological innovation, through which the impact of smoking on Chinese could be evaluated within relative short period with less resource consumption.
The precancerous lesion was defined by World Health Organization (WHO), in 1978 as a morphologically altered tissue associated with a significantly increased risk of cancer. Precancerous lesions of oral cavity include oral submucous fibrosis (OSMF), Plummer Vinson syndrome, erosive lichen planus, dyskeratosis congenita, chronic hyperplastic candidiasis, Cowden's syndrome, discoid lupus erythromatosus, dystrophic epidermolysis bullosa, and xeroderma pigmentosa . In 2005, WHO decided to use the term 'Potentially Malignant Disorders (PMD)' as it describes that the pathological condition may transform into cancer. Precancerous lesions that are identified PMD are leukoplakia, erythroplakia, palatal changes associated with reverse smoking, oral lichen planus, OSMF, and discoid lupus erythromatosus . Causative factors for PMDs include human papilloma virus (HPV), candida, tobacco, 'gutkha', areca nut, vitamins (such as, A, B, C, D, and E) deficiency and minerals (such as, iron, calcium, copper, zinc and magnesium etc) deficiency .
Tobacco is a plant called 'nicotiana tabacum', whose dried leaves are used to make different forms of tobacco . All forms of tobacco contain nicotine - the chemical responsible for addiction [2,3]. Although extremely lethal, tobacco is cultivated in many regions of the world and is legally available .
Tobacco products can be broadly classified into smoked and smokeless products. Smoked forms of tobacco are those substances which are burnt and the resultant smoke is inhaled or held in the mouth . While on the other hand, smokeless tobacco products are used either orally or nasally without burning the product . The different types of tobacco products have been listed below [4,5,6].
tobacco smoking during pregnancy and lactation remains a major public health concern and is associated with a higher risk of poor pregnancy outcomes. It is well known that the adverse environmental exposure within the critical window of gestation period can initiate aberrant fetal development that leads to cardiovascular diseases in adulthood, a phenomenon called programming. Here, we summarize several epidemiological and experimental studies that demonstrate the association between maternal nicotine or tobacco exposure during pregnancy and the development of cardiovascular dysfunction. This chapter also presents some novel epigenetic molecular mechanisms underlying the maternal smoking/nicotine-induced fetal programming of the adult cardiovascular disease. Taken together, a smoke-free environment during pregnancy is essential to improving health outcomes and reducing the risk for future cardiovascular diseases. A better understanding of the epigenetic molecular mechanism underlying the effects of perinatal smoking exposure on programming could provide novel insights into the therapeutic strategies for cardiovascular diseases.
The current chapter discusses recent findings in humans on genetoxic effects on the fetus of prenatal exposure to smoke tobacco. Tobacco Smoking is the most widespread substance dependence in the World, and is a rapidly increased including in pregnant women and serious public health problem worldwide. Nicotine readily crosses the placenta and the fetuses of mothers. Recent studies have suggested a direct contribution of nicotine the addictive component of tobacco and tobacco smoke to human carcinogenesis, and it remains the most common harmful substance to which pregnant women are exposed. Smoking during pregnancy increases maternal health, and also it has deleterious effects on the fetus; premature birth, intrauterine fetal death, intrauterine growth retardation and congenital anomalies. It is known that cigarette smoking has genotoxic effects and causes mutations.
Tobacco is a powerful addictive substance which is deliberately consumed all over the world. People enjoy tobacco and its products via various methods in different parts of world. It is consumed either orally by smoking through cigarettes, pipes, cigar, bidi, hukkah, chhutta etc. or chewed in the form of raw leaves as khaini; or altered form as pellets, plugs, gutkha/pan masala and snus/dripping or e-cigarettes. It is also taken (sniffed) through nasal route as nasal snuff (luktsnus). Chewing/Smokeless tobacco is consumed with or without flavouring agents and sweeteners [1,2]. In this method tobacco product is placed between cheek and gums or lower lip and teeth. Then it is slowly chewed or crushed to release flavour and nicotine and unwanted juices are expectorated at short intervals till the content finishes. So, it is also known as spitting tobacco.
1. Yihunie Lakew
2. Sutapa Agrawal
3. Dr. Wanxia