Exposure, Effects of Second-Hand Smoke

By: Dr. Magdy Badran

Second-hand smoke (SHS) is smoke from burning tobacco products, such as cigarettes, cigars, or pipes. SHS also is a smoke that has been exhaled, or breathed out, by the person smoking. SHS is also known as environmental tobacco smoke. SHS is one of the most important and most widespread exposures in the indoor environment. Most exposure to SHS occurs in homes and workplaces. People are also exposed to SHS in public places such as in restaurants, cars, and other vehicles.

 

Women and children suffer more

The tobacco epidemic is one of the biggest public health threats the world has ever faced, killing more than 7 million people a year. More than 6 million of those deaths are the result of direct tobacco use while around 890 000 are the result of non-smokers being exposed to SHS.

Women suffer more from the impacts of SHS as they are 50% more likely to be non-smokers than men. Half of the world’s children are exposed to SHS. In terms of years of life loss, children are by far the most affected from SHS, as most of their SHS deaths occur from respiratory infections during the first few years of life.

 

Exposure to SHS is strongly associated with a number of adverse effects on children, involving, in particular, the respiratory tract. The vast majority of children exposed to tobacco smoke is accidental. Children’s exposure is involuntary, arising from smoking, mainly by adults, in places where children live, work, and play. Baby girls who are exposed to cigarette smoke while in their mothers' wombs are more likely to experience miscarriage as adults.

 

SHS and circulation

Smoking damages blood vessels and can make them thicken and grow narrower. SHS can make your heart beat faster and your blood pressure goes up. Smoking, either active or passive, can cause cardiovascular disease via a series of interdependent processes, such as enhanced oxidative stress, hemodynamic and autonomic alterations, endothelial dysfunction, thrombosis, inflammation or hyperlipidemia. Internationally, 25% of middle-aged cardiovascular deaths are attributable to smoking. Even exposure to small quantities—e.g. occasional smoking, passive smoking, a few cigarettes per day—is sufficient to have deleterious consequences.

Nicotine is a poison

 

One cigarette delivers 1.2-2.9 mg of nicotine, and the typical one-pack-per-day smoker absorbs 20-40 mg of nicotine each day. Nicotine deregulates cardiac autonomic function, raises heart rate, causes coronary and peripheral vasoconstriction and increases myocardial workload. In addition, nicotine is associated with insulin resistance, increased serum lipid levels, and intravascular inflammation that contributes to the development of atherosclerosis.

Nicotine stimulates the release of adrenaline by the adrenal cortex, leading to the increased serum concentrations of free fatty acids (FFA) observed in smokers. The increased release of FFA in the heart raises myocardial oxygen consumption, adding to the myocardial workload.

Smoking is associated with elevated serum concentrations of total cholesterol and triglycerides. On the other hand, smoking lowers serum concentrations of high-density lipoprotein cholesterol, a powerful protective factor against the development of atherosclerosis.

 

Carbon monoxide - the silent killer

Carbon monoxide is produced from the incomplete combustion of carbon-containing substances, such as gasoline and tobacco. Carbon monoxide exposure has been implicated in the process of atherosclerosis, contributing to the accumulation of cholesterol in the aorta and coronary arteries and endothelial damage (Endothelium refers to cells that line the interior surface of blood vessels).

Inhalation of cigarette smoke, by either active or passive smokers, decreases the supply of oxygen to the tissues. Carbon monoxide decreases the oxygen-transporting capacity of blood because of its much higher hemoglobin affinity 200 times that of oxygen.

Carboxyhemoglobin byproduct of this reaction is unable to carry oxygen, reducing its availability to tissues and causes chemical asphyxia and hypoxia. In addition, myoglobin (a protein found in the muscle cells) binds with carbon monoxide so that the heart muscle does not take up the necessary oxygen.

 

No safe level of exposure to SHS

There is no risk-free level of SHS exposure; even brief exposure can be harmful to health. Tobacco smoke contains more than 7,000 chemicals, including hundreds that are toxic and about 250 that can cause cancer even in people who have never smoked.

 

Health effects of SHS on children

Children face a greater risk than adults of the negative effects of SHS. Young children have little control over their surroundings. Babies can't move to another room because the air is smoky. They depend on the adults in their lives to make sure their environment is safe.

When the air is tainted with cigarette smoke, young, developing lungs receive a higher concentration of inhaled toxins than do older lungs because a child's breathing rate is faster than that of adults.

Adults breathe in and out approximately 14 to 18 times a minute, and newborns can breathe as many as 60 times a minute. Up until a child is about 5 years old, the respiratory rate is quite fast.

In children, SHS causes the following: ear infections, more frequent and severe asthma attacks, respiratory symptoms (for example, coughing, sneezing, and shortness of breath), respiratory infections (bronchitis and pneumonia) and a greater risk for sudden infant death syndrome.

 

SHS and pregnancy

Babies whose mothers smoke during pregnancies often weigh less at birth than those born to non-smoking mothers. Low birth weight is a leading cause of infant death.

Mothers smoking during pregnancy have an altered local and systemic immune system. The smoking-induced damages for the unborn offspring manifest themselves at various times in life, some being clearly visible from birth on, others becoming evident only in the following generation.

Maternal cigarette smoking during pregnancy may affect fetal kidney development, cause congenital heart defects, decrease the size of the fetal brain, decrease pulmonary function in offspring later in life, increase pediatric hospitalization and increase mortality because of respiratory infections in early childhood.

 

Cigarettes cause infantile colic

Babies can be exposed to smoke while they're still in the womb, through breast milk, or by being around a smoker after birth. Exposure to cigarette smoke and its metabolites may be linked to elevated risks of infantile colic, smoking is linked to increased plasma and intestinal motilin levels and higher-than-average intestinal motilin levels are linked to elevated risks of intestinal colic. Motilin increases the contractions of the stomach and intestines, increasing the movement of food through the gut.

 

What you can do

You can protect yourself and your family from SHS by: quitting smoking if you are not already a nonsmoker, not allowing anyone to smoke anywhere in or near your home, not allowing anyone to smoke in your car, even with the windows down. Make sure your children’s daycare center and schools are tobacco-free. Seek out restaurants and other places that do not allow smoking. Teach your children to stay away from SHS.

Every person should be able to breathe tobacco-smoke-free air. Hard-hitting anti-tobacco advertisements and graphics pack warnings – especially those that include pictures – reduce the number of children who begin smoking and increase the number of smokers who quit.

Graphic warnings can persuade smokers to protect the health of non-smokers by smoking less inside the home and avoiding smoking near children. Mass media campaigns can also reduce tobacco consumption by influencing people to protect non-smokers and convincing youths to stop using tobacco. Tobacco taxes are the most cost-effective way to reduce tobacco use, especially among young and poor people.