Tobacco: Impacts on Health

February 7, 2016

Smoking and smokeless tobacco usage not only impacts the user but can also harm those exposed to tobacco smoke. Studies have shown that tobacco is also detrimental to the health of the children and grandchildren of tobacco users. In 1964, the U.S. Surgeon General’s office released a landmark report on the health effects of tobacco usage ⁽¹⁾. We now know that all forms of tobacco are harmful to the user and, frequently, to those nearby. Tobacco’s negative impact can even extend to unborn future offspring of users.

Smoking tobacco

Firsthand exposure

What is it?
- Firsthand exposure refers to the tobacco smoker’s exposure to tobacco smoke and its many toxins.

Prevalence
- In 2012, approximately 18.1% of U.S. adults (at least 18 years old) were cigarette smokers. Among the smokers, 78.4% of them smoked every day ⁽²⁾.

Health problems
- There are many health-related issues associated with smoking tobacco, including cancer, brain damage, heart disease, stroke, lung disease, and wrinkles.
  - Cancer
    - Smoking tobacco is linked to many types of cancers, including cancer of the mouth, nose, throat, larynx, esophagus, lung, stomach, liver, pancreas, kidney, blood and bone marrow, colon, and intestine ⁽³⁾.
  - Heart disease and stroke
    - Cigarette smoking causes coronary heart disease, the leading cause of deaths in the U.S. It has been found that cigarette smokers are 2-4 times more likely to develop coronary heart disease than nonsmokers and are twice as likely to have a stroke ⁽⁴⁾.
  - Brain damage
    - Present in all forms of tobacco, the carcinogen NNK has been found to cause brain damage by causing immune cells to attack healthy brain cells ⁽⁵⁾.
  - Wrinkles
    - Although wrinkles are not a serious health concern, studies have found that smoking is linked to the breakdown of elastin fibers, which are the protein bundles responsible for the skin’s ability to stretch and relax. Loss of elastin fibers results in skin wrinkles ⁽⁶⁾.

Lung disease
- Chronic obstructive pulmonary disease (COPD) is a broad term that covers lung diseases including emphysema and chronic bronchitis. COPD refers to serious lung diseases. Patients have less airflow through their airways, making it harder for them to breathe. This condition can occur when the tiny air sacs in the lungs lose their ability to stretch and shrink, when the walls separating the air sacs become damaged or inflamed, or when the airways are obstructed by abnormal amounts of mucus ⁽³⁾⁽⁷⁾⁽⁸⁾⁽⁹⁾. Smoking is responsible for 9 out of 10 COPD-related deaths ⁽⁷⁾. Smoking has also been found to trigger asthma attacks ⁽¹⁰⁾.

Loss of Y chromosome
- Recent studies suggest that male smokers are at a significantly greater risk of losing their Y chromosome. Specifically, male smokers were found to be up to 4 times more likely to have blood cells that have lost the Y chromosome ⁽¹¹⁾. The Y chromosome is the chromosome that contains sex-determining genes. Previous studies have suggested that loss of Y chromosome may be associated with a shorter lifespan and a greater risk for developing cancer ⁽¹²⁾.

Secondhand exposure

What is it?
- Secondhand exposure to smoke is the involuntary or passive exposure of nonsmokers to tobacco smoke. The two types of tobacco smoke relevant to secondhand smoke exposure are called mainstream smoke and sidestream smoke. Mainstream smoke refers to the smoke that is exhaled by a smoker, while sidestream smoke refers to the smoke that comes from the lit end of a cigarette, cigar, pipe, and other tobacco-smoking devices. While all secondhand smoke exposure is regarded as harmful, sidestream smoke is considered to be more toxic than mainstream smoke because sidestream smoke contains higher concentrations of carcinogens ⁽¹³⁾.

When a person is exposed to secondhand smoke, the nicotine in the smoke is changed by the body (metabolized) into cotinine, a nicotine byproduct, which can be detected in saliva, urine, and blood samples ⁽¹⁴⁾⁽¹⁵⁾.

Prevalence
- Although secondhand smoke exposure (measured by cotinine levels) has decreased among U.S. nonsmokers and among all racial and ethnic groups, it still remains higher among non-Hispanic black Americans than among non-Hispanic white Americans and Mexican Americans. The percentage of nonsmokers who had measurable levels of cotinine in their system decreased from 87.9% (1988-1991) to 40.1% (2007-2008). It was estimated that approximately 88 million U.S. nonsmokers were exposed to secondhand smoke in 2007-2008 ⁽¹⁶⁾⁽¹⁵⁾.

Health problems
- There are many health-related issues associated with secondhand smoke, including cancer, pregnancy problems, heart disease, stoke, and lung problems.
  - Cancer
    - Secondhand smoke exposure has been found to increase a nonsmoker’s risk of developing lung cancer by 20-30% ⁽¹⁴⁾⁽¹⁵⁾. Ongoing research suggests that secondhand smoke exposure may increase a nonsmoker’s risk of developing breast cancer ⁽¹³⁾.
  - Birth and pregnancy
    - Secondhand smoke exposure has been found to increase the risk of a miscarriage, stillborn birth, and other pregnancy-related problems ⁽¹³⁾.
  - Heart disease and stroke
    - Secondhand smoke exposure has been found to increase a nonsmoking adult’s risk of getting heart disease by 25-30% and has also been found to increase a nonsmoking adult’s risk for heart attack and stroke ⁽¹⁴⁾⁽¹⁵⁾.
  - Lung disease
    - Secondhand smoke exposure is responsible for approximately 7,500 to 15,000 annual hospitalizations of U.S. children aged 18 months and younger and is responsible for approximately 150,000 to 300,000 annual cases of bronchitis and pneumonia in U.S. children aged 18 months and younger ⁽¹⁴⁾⁽¹⁵⁾. Secondhand smoke has also been found to trigger asthma attacks ⁽¹⁰⁾.

Preventative measures
- Ways to avoid secondhand smoke exposure and to protect from its damaging effects include, but are not limited to, the following: not being exposed to secondhand smoke, preventing indoor smoking, filtering the air, and ventilating buildings ⁽¹³⁾.

Thirdhand exposure

What is it?
- Thirdhand exposure to smoke refers to the involuntary or passive absorption, through the skin or ingestion through the mouth, of carcinogenic tobacco residues that may be found on surfaces or mixed with the dust in the air. Thirdhand exposure is most prevalent among babies and children who are more inclined to touch surfaces and subsequently lick their hands. The health effects of thirdhand exposure to smoke are still under study ⁽¹³⁾.

Transgenerational effects

What is it?
- Tobacco exposure not only affects the health of the smoker but can also affect the health of the smoker’s children, grandchildren, and so on. The toxins and carcinogens present in tobacco smoke can cause unfavorable genetic and epigenetic* changes to the smoker’s DNA as well as to the smoker’s descendants’ DNA, which could lead to genomic instability and damaged DNA repair systems. The mechanisms of how this works is still under study ⁽¹⁷⁾.

*Epigenetic changes refer to slight chemical modifications that control the “on” or “off” status of a gene. These changes are not the same as mutations, which refer to alterations of the ‘letters’ of the DNA sequence itself. An epigenetic change would be like changing the letter ‘a’ into the letter ‘A’. They are similar, but not the same. A mutation would be like changing the letter ‘a&’ to the letter ‘b’. They are very different.

Recent studies of epigenetic changes suggest that the amount of methylation (a form of epigenetic change) of the F2RL3 gene may serve as a measure of a person’s lifetime exposure to firsthand tobacco smoke. This means that F2RL3 methylation has the potential to help determine a person’s risk for developing smoking-related cardiovascular diseases ⁽¹⁸⁾. Other studies have found that the toxins in tobacco smoke can lead to epigenetic changes within reproductive cells (sperm/egg). Specifically, changes in the expression of important microRNAs (miRNAs) in human spermatozoa have been found. Researchers believe that these epigenetic changes are heritable and may affect sperm health and the development of the embryo ⁽¹⁹⁾. A study using rats suggests that maternal smoking during pregnancy could result in nicotine-induced asthma in children, grandchildren, and subsequent generations ⁽²⁰⁾⁽²¹⁾.

E-cigarette poisoning

What is it?
- E-cigarette poisoning happens when e-cigarette liquid containing nicotine is ingested, inhaled, or absorbed through the skin or eyes. This can lead to vomiting, nausea, eye irritation, heart problems, and even death. According to a CDC study, there has been an increase in the number of calls received by U.S. poison centers regarding e-cigarette liquids (1 call per month in 2010 to 215 calls per month in 2014). There was no similar increase in the number of calls received regarding conventional cigarettes. Furthermore, approximately 51% of calls regarding e-cigarette poisoning involved children under the age of 5, and approximately 42% of calls regarding e-cigarette poisoning involved people aged 20 and older⁽²²⁾. Another recent source reports that in 2013, 1,351 calls were received by poison controls centers in the U.S. regarding e-cigarette liquids, three times more than the number of calls received in 2012. Furthermore, 365 of those 1,351 calls were referred to hospitals, also three times more than in 2012. Currently, e-cigarette liquids are sold online to the general public by the liter (about one quart) at nicotine concentrations as high as 10% ⁽²³⁾. According to a study conducted at Washington University School of Medicine in St. Louis, many parents fail to safely store e-cigarette liquids and few parents were aware of the risks associated with unsafe e-liquid storage. 36% of the e-cigarette users surveyed did not lock up e-liquid bottles after use and did not use childproof caps. Also among those surveyed, 3% reported instances where their child attempted to consume the e-liquid ⁽²⁴⁾. The FDA is currently planning e-cigarette liquid regulations ⁽²⁵⁾.

E-cigarette fires and explosions

While fires and explosions caused by e-cigarettes are rare, they can cause serious injuries and burns when they do occur. Between 2009 and 2014 in the United States, 25 incidents involving e-cigarette explosion and fire were reported. These 25 incidents were associated with 9 injuries and 0 deaths. ⁽²⁶⁾ Most e-cigarette explosions result from the spontaneous ignition and explosion of e-cigarette batteries during e-cigarette use or during e-cigarette battery charging. These explosions can cause internal and external burns to the user’s face, neck, throat, lungs, and more. ⁽²⁷⁾⁽²⁸⁾ E-cigarette batteries have also spontaneously exploded when it is not in use or charging. ⁽²⁹⁾

Smokeless tobacco

Firsthand exposure

What is it?
- Firsthand exposure refers to the user’s exposure to the dangerous chemicals found in smokeless tobacco.

Prevalence
- It was estimated that in 2012, about 9 million people aged 12 and older living in the U.S. used smokeless tobacco. Smokeless tobacco usage is higher among younger age groups. According to CDC’s 2012 National Youth Tobacco Survey, smokeless tobacco usage is higher among high school-aged people than among young adults between the ages of 18 and 25 ⁽³⁰⁾.

Health problems
- There are many health-related issues associated with using smokeless tobacco, some of which include cancer, heart disease, mouth sores (leukoplakia), and dental problems.
  - Cancer
    - Smokeless tobacco usage is linked to various types of cancers, such as those of the mouth, tongue, cheek, gum, throat, esophagus, stomach, and pancreas ⁽³⁰⁾.
  - Heart disease
    - Although more studies are needed to identify the role of smokeless tobacco in heart diseases, current data suggests that smokeless tobacco users are more likely to have heart disease, high blood pressure (hypertension), and heart failure than those who do not use smokeless tobacco ⁽³⁰⁾.
  - Dental
    - Smokeless tobacco usage is linked to cavities and tooth decay ⁽³⁰⁾.
  - Leukoplakia
    - Leukoplakia refers to white mouth lesions that can become cancerous. These oral soft tissue abnormalities are most commonly found in smokeless tobacco users, at the site where smokeless tobacco is placed ⁽⁵⁾.

Additional statistics

Deaths

Smoking tobacco is responsible for approximately 1 in every 5 deaths (includes exposure to firsthand and secondhand smoke), which translates to more than 480,000 deaths in the U.S. each year. Men account for approximately 279,000 of those annual deaths, while women account for approximately 202,000 of those annual deaths ⁽³¹⁾ ⁽³²⁾ ⁽³³⁾. As a comparison, there are 525,949 minutes per year, so that works out to nearly one death from smoking every minute.

From 2005-2009, it was estimated that approximately 42,000 annual deaths among nonsmokers were due to secondhand smoke exposure. Among those 42,000 annual deaths, approximately 7,300 deaths were due to lung cancer, while approximately 34,000 annual deaths were due to heart disease

⁽¹⁵⁾

. It is estimated that at least 30% of all cancer deaths are due to tobacco use

⁽³⁴⁾

. It was also estimated that, since 1964, approximately 2.5 million nonsmokers have died due to secondhand smoke exposure

⁽¹⁵⁾

Life expectancy

According to the World Health Organization, 1 in 2 lifetime smokers will die of a disease associated with tobacco use ⁽³⁵⁾. According to the Centers for Disease Control & Prevention (CDC), U.S. nonsmokers live at least 10 years longer than U.S. cigarette smokers ⁽³¹⁾ ⁽³²⁾ ⁽³⁶⁾.

Preventable deaths

An estimated 1 out of every 3 cancer deaths in the U.S. could be prevented if no one smoked tobacco.A smoker’s risk for getting mouth, throat, esophageal, and bladder cancer decreases by half within 5 years of quitting smoking, and a smoker’s risk of dying from lung cancer decreases by half within 10 years of quitting smoking ⁽³⁷⁾.

[“source -pcworld”]

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