Tobacco and Alcohol Associated with Several Diseases

By Dr. John H. Holbrook

Medical science has documented that the use of tobacco and alcohol is associated with premature death and disability from several diseases including coronary heart disease, cancer, emphysema, chronic bronchitis, and cirrhosis. Although less publicized, studies have also demonstrated numerous adverse effects of these substances on the nervous system.

A burning cigarette is a miniature factory that produces several thousand chemicals. A pack-a-day cigarette smoker puffs more than 50,000 times a year, thus delivering a myriad of substances to vital organs, including the brain. Cigarette smoke constituents, such as nicotine, carbon monoxide and hydrogen cyanide, exert damaging effects on the nervous system.

Nicotine is both a stimulant and depressant of the nervous system and indirectly adversely affects many other organ systems. It is thought to play a major role in the development of addiction to tobacco products.

Carbon monoxide is a toxic gas that interferes with the transport and delivery of oxygen to cells. Cigarette smokers demonstrate 2 to 15 times as much blood carbon monoxide as non-smokers. Even low levels of blood carbon monoxide can impair intellectual function and coordinated, fine movements.

Hydrogen cyanide is a potent toxin that inhibits cellular respiration and produces deficient levels of intracellular oxygen.

Cigarette smoking increases the risk for developing narrowed or occluded cerebral and coronary arteries; these vascular disorders may lead to inadequate oxygen delivery to the brain and to the sudden onset of neurologic deficits (stroke). Women who use both tobacco and oral contraceptives face more than a 20-fold increase in risk for one type of stroke. Chronic lung disorders caused by smoking, emphysema and chronic bronchitis, may lead to impaired oxygen delivery to the brain and retention of excess amounts of carbon dioxide; the resulting disturbance of cerebral function may progress to stupor or coma.

Intrauterine exposure to the constituents of tobacco smoke may be harmful for the unborn child’s nervous system. Women who smoke during pregnancy deliver babies that are smaller than those born to non-smoking mothers; this retardation of fetal growth involves all dimensions, including head size. Long-term studies have shown that children born to women who smoke during pregnancy also have deficiencies in intellectual growth, emotional development, and behavior, compared to children born to non-smoking mothers. A British study of several thousand women who smoked during pregnancy demonstrated that their 11-year-old children were several months behind in reading, mathematics, and general ability, compared to children born to women who did not smoke during pregnancy.

In summary, tobacco smoke disturbs the structure and function of the nervous system. Furthermore, tobacco smoke contains numerous inadequately studied substances that might be anticipated to exert deleterious effects on the nervous systems. What these effects might be is currently an unanswered question.

In contrast to tobacco, alcoholic beverages contain a single substance of medical importance, ethanol. It is a depressant of the nervous system. Ethanol interferes with learning, impairs judgment and disturbs the ability to reason. Acute alcoholic intoxication presents a spectrum that may vary from slurring of speech and incoordination to coma and death. Withdrawal from alcohol may result in tremulousness, hallucinations, seizures, and death due to trauma, infection, or circulatory collapse. Because chronic alcoholics rarely eat balanced diets, they often develop diseases such as pellagra, beriberi, scurvy and anemia, which are caused by nutritional deficiencies.

These disorders commonly affect function of the peripheral nerves, the spinal cord and the brain. Alcoholics may develop poorly understood neurologic diseases that result in selective or generalized atrophy of the brain.

In recent years, much has been learned about the adverse effects of alcohol on the fetus. The most severe effects are seen in infants born to alcoholic mothers; these infants may demonstrate the fetal alcohol syndrome with severe mental retardation and multiple birth defects. Because no safe level of alcohol exposure has been established for the developing fetus, physicians recommend that women avoid alcohol consumption during pregnancy.

Both tobacco and alcohol are addictive substances. The majority of current cigarette smokers would like to stop smoking, but less than 20 percent of those currently attempting to stop are successful. The tobacco withdrawal syndrome is characterized by a craving for tobacco, restlessness, sleep disturbances, impaired intellectual function, slowing of the pulse, and an altered brain wave pattern. The physiological changes usually last only a few days, while the psychological symptoms may last much longer.

The addictive nature of tobacco and alcohol use causes consumers of these substances to pay a very high emotional, social, and intellectual toll.

In conclusion, tobacco and alcohol exert numerous adverse effects on the nervous system of the fetus, child, and adult. Those who avoid these substances are more likely to enjoy optimum function of their minds and even to “find wisdom and great treasures of knowledge.”

• Dr. Holbrook, associate professor of internal medicine at the University of Utah, is an editor for the U. S. Surgeon General’s Report on Smoking and Health and is a consultant for the National Cancer Institute.