Effects of Tobacco on Health
Tobacco is extracted from around 65 known species of the tobacco plant of which the one that is grown commercially and widely as a source of tobacco is Nicotianatobaccum. Most of the tobacco from Northern India and Afghanistan comes from the species Nicotianarustica.
The growing use of tobacco is a cause of great concern around the world due to its serious effects on health.Non-communicable diseases (NCDs) like ischemic heart diseases, cancers, diabetes, chronic respiratory diseases are the leading causes of death globally and associated with tobacco use. Available data from WHO demonstrate that thirty-eight million people die each year from NCDs, of which nearly 85% of NCD deaths occur in low- and middle-income countries.
According to WHO statistics for 2010 in India, NCDs are estimated to account for 53% of all deaths. Of these deaths, cardiovascular diseases and diabetes are the most common causes of deaths in India.
This huge burden of NCDs can be attributed to increasing use of tobacco. Tobacco is a major risk factor for a number of diseases affecting all age groups. WHO data shows that tobacco uses kill nearly six million people in a year. Around five million of those deaths are the result of direct tobacco use while more than 600,000 are the result of non-smokers being exposed to second-hand smoke. One person dies every six seconds due to tobacco. Up to half of current users will eventually die of a tobacco-related disease.
The situation is equally bad in India with estimated number of tobacco users being 274.9 million where 163.7 million users of only smokeless tobacco, 68.9 million only smokers and 42.3 million users of both smoking and smokeless tobacco as per Global Adult Tobacco Survey India (GATS). It means around 35% of adults (47.9% males and 20.3% females) in India use tobacco in some form or the other. Use of smokeless tobacco is more prevalent in India (21%).
Composition of tobacco
Tobacco products contains around 5000 toxic substances. Most important and dangerous constituents are:
- Carbon Monoxide
Nicotine is the major cause of the predominant behavioral effects of tobacco. It is a poisonous substance leads to addiction. Nicotine influences and reinforces all tobacco-use behavior. After absorption, nicotine travels rapidly to the brain, in a matter of seconds, therefore, the psycho-active rewards associated with smoking occur quickly and these rewards are highly reinforced. Nicotine binds to the receptors in the brain where it influences the cerebral metabolism. Nicotine is then distributed throughout the body, mostly to skeletal muscles. Development of tolerance to its own actions is similar to that produced by other addictive drugs.
Carbon mono-oxide reduces the amount of oxygen blood can carry and causes shortness of breath. Tar is a sticky residue which contains benzopyrene, one of the deadliest cancer causing agents known. Other compounds are carbon dioxide, nitrogen oxides, ammonia, volatile nitrosamines, hydrogen cyanide, volatile sulfur containing compounds, volatile hydrocarbons, alcohols, aldehydes and ketones. Some of these compounds are known to cause cancers of various organs of the body.
Mechanism of action
Nicotine has structural similarity to a body neuro-transmitter acetylcholine (Ach) which conveys information from one neuron to another. Acetylcholine is an important neurotransmitter involved in systems concerned with mental and physical arousal, learning and memory, and several aspects of emotion. There are also other receptors for acetylcholine in the body, apart from the ones at synapses. They are also found at the junction of nerve and muscles and nerves and certain glands. Acetylcholine receptors throughout the body are traditionally classified as nicotine receptors (those that respond to nicotine) and muscarine receptors (those that respond to muscarine). The ability of nicotine to combine with acetylcholine-receptors means that it can exert actions like acetylcholine at all synapses where nicotine acetylcholine-receptors (nAChRs) are present and can trigger impulses.
Forms of tobacco intake
- Cigarette — Most common and most harmful
- Bidi — most commonly used form in India
- Cigar -
- Hookah (Hubble bubble)
- Tobacco chewing
- Kreteks (clove cigarettes)
- Snuff — Moist & Dry
- E-cigarette — recent intruder in the list
When non-smokers are exposed to smoke containing nicotine and toxic chemicals emitted by smokers it is called passive smoking or exposure to second hand smoke.
Risk factors for tobacco initiation
Following factors influence the predilection for tobacco use:
- Developmental aspects of adolescent age group include (a) establishing independence and autonomy, (b) forming a coherent self-identity and (c) adjusting to psycho-social changes associated with physical maturation.
- Gender: tobacco use is more common among males in India.
Low emotional stability and risk taking behavior are more common in tobacco users. Existence of some mental disorders also increases the risk of tobacco use.
3.Social and Environmental:
Parental influence, lower education status, attraction towards role models, cultural practices, etc.
Consequences of tobacco use
Various effects of tobacco use are as follows:
- Economic loss
- Health loss
- Environmental loss
Tobacco is considered as a major behavioral risk factor for non-communicable diseases one of the leading causes of death. Treatment of cardiovascular diseases and cancer imposes maximum financial burden on the individual and family. For cultivation of tobacco crop forests are destroyed. Burning of tobacco produces number of toxicants in environment. Manufacturing, packaging and transportation also cause environmental pollution.
Cancers associated with tobacco
Tobacco is also associated with cancer of respiratory tract, lung, upper gastrointestinal tract, liver, pancreas, kidney, urinary bladder, oral cavity, nasal cavity, cervix, etc. Smokeless tobacco (chew tobacco, snuff etc.) is a major cause of cancer of the oral cavity.
Risk of developing cancer increases with:
- Duration of use of tobacco
- Number of tobacco product use per day
- Degree of inhalation
- Stroke is vascular disease of the brain where tobacco causes either constrict of blood vessels or rupture leading to loss of consciousness and paralysis.
- Tobacco affects coronary vessels of the heart leading decrease of blood supply or death of heart muscles which is known as ischemic or coronary heart disease. This in turn causes cardiac arrest.
- Smoking acts synergistically with other risk factors like high cholesterol and blood pressure to increase the risk of Coronary Heart Diseases (CHD).
- Chronic Obstructive Pulmonary Disease: It includes chronic bronchitis and emphysema
- Asthma: Smoking is associated with acute attacks of asthma
Effect on pregnancy and its outcome
- Bleeding during pregnancy
- Ectopic pregnancy
- Premature delivery of baby
- Abnormalities of the placenta
Effects on newborns and childhood
Maternal tobacco use during pregnancy and exposure of child to second hand smoke in childhood is known to be a risk factor for following conditions:
- Maternal smoking is associated with congenital malformations in baby like orofacial clefts, clubfoot and atrial-septal defects.
- Increased risk of allergies
- Higher blood pressure in childhood
- Increased likelihood of obesity
- Stunted growth
- Poorer lung function
- Increased likelihood of developing asthma
Following conditions are known to worsen if case of tobacco use:
- Rheumatologic conditions: Rheumatoid arthritis
- Kidney damage
- Eye Disease: Age-Related Macular Degeneration
- Dental Disease like caries
- Inflammatory bowel diseases
- Erectile dysfunction
Quit It !
Smoking is an addiction that requires determination and effort to overcome. It is important to have a plan in place since the entire quitting process is a journey and cannot be achieved in one go. To break free of a habit it is first important to understand the pattern.
Quitting smoking cuts cardiovascular risks. Just 1 year after quitting smoking, your risk for a heart attack drops sharply.
· Within 2 to 5 years after quitting smoking, your risk for stroke could fall to about the same as a nonsmoker’s.
· If you quit smoking, your risks for cancers of the mouth, throat, esophagus, and bladder drop by half within 5 years.
· Ten years after you quit smoking, your risk for lung cancer drops by half.
Sources:NHP India ;CDC USA