Smoking Health Risks:

Health Risks

Effects on the Lungs

According to the American Lung Association, smoking is directly responsible for about 90 percent of the deaths due to lung cancer. Smoking is also responsible for the majority of deaths due to chronic obstructive pulmonary disease (COPD), which includes emphysema and chronic bronchitis.

A study in the July 2006 American Journal of Respiratory and Critical Care Medicine showed that smokers with asthma who give up smoking can improve their lung function in as little as 1 week. The small study involved 21 smokers with asthma. Ten of them quit smoking for 10 weeks, while the others continued to smoke. After just a week, lung function test scores in those who stopped smoking improved considerably. In less than 2 months, lung function scores among those who stopped smoking improved by more than 15%.

Study authors say their findings show that there is a “reversible component to the harmful effects of smoking on the airways in asthma.”

Secondhand Smoke

Secondhand smoke is produced by a burning cigarette or other tobacco product. An estimated 4 million children a year get sick from being around secondhand smoke. Parental smoking has been shown to affect the lungs of infants as early as the first 2 – 10 weeks of life, and such abnormal lung function could persist throughout life.

Exposure to secondhand smoke in the home increases the risk for asthma and asthma-related emergency room visits in children who have existing asthma.

Parental smoking is believed to increase the risk for lower respiratory tract infections (such as bronchitis or pneumonia) by 50%. Environmental exposure to smoke is thought to be responsible for 150,000 – 300,000 such cases of such every year.

Effects on the Heart and Blood Vessels

All forms of tobacco raise one’s heart attack risk. Smoking, chewing tobacco, and being exposed to secondhand smoke greatly increase one’s risk of a heart attack. In some cases, the risk of heart problems in people who smoke or are epoxies to smoke may be three times greater, according to a study published in the Lancet. However, the study also found that the risk of a heart attack among those who stopped smoking slowly decreased over time.

Effects on Male Fertility and Impotence

Smoking has a negative affect on a man’s sexuality and fertility. Heavy smoking is frequently cited as a contributory factor in impotence because it decreases the amount of blood flowing into the penis. One study noted that among men with high blood pressure, smoking caused a 26-fold increase in impotence.

Smoking impairs sperm motility, reduces sperm lifespan, and may cause genetic changes that can affect a man’s offspring. One 2002 trial found that men or women who smoke have lower success rates with fertility treatments. An earlier study reported that men who smoke also have lower sex drives and less frequent sex.

Effects on Pregnancy and Female Infertility

Studies have linked cigarette smoking to many reproductive problems. Continuing to smoke during pregnancy may also cause health problems in the baby.

Negative effects of smoking on female fertility include:

• Greater risk for infertility. Women at greatest risk for fertility problems are those who smoke one or more packs a day and who started smoking before age 18.
• Earlier menopause. Women who smoke tend to start menopause at an earlier age than nonsmokers, perhaps because toxins in cigarette smoke damage eggs.
• Pregnancy complications. Women who smoke have a greater risk for ectopic pregnancy and miscarriage.

Effects on Unborn Child. Smoking during pregnancy is harmful to an unborn child in many ways. Smoking reduces the mother’s folate levels, a B vitamin that is important for preventing birth defects. Pregnant women who smoke increase the risk for stillbirth, prematurity and low birth weight in their babies. Infant mortality rates in pregnant smokers are increased by 33%, mostly because of low birth rate.

Some women carry particular genes that may make it especially likely that they will deliver low birth weight infants if they smoke, although newborns of all female smokers have a greater risk for low weight.

The good news is that women who quit before becoming pregnant or even during the first trimester reduce the risk for a low birth weight baby to that of women who never smoked.

Children of mothers who smoke during pregnancy may also be at increased risk for obesity and diabetes.

Women who want to become pregnant should try smoking cessation aids before they try to conceive and make all attempts to quit. If new mothers cannot quit, they should be sure not to smoke in the same room as their infant. This simple behavior can considerably reduce the risks to the child.

Effects on Bones and Joints

Smoking has many harmful effects on bones and joints:

• Smoking can keep new bone from forming. Women who smoke are at high risk for loss of bone density and osteoporosis.

• Postmenopausal women who smoke have a significantly greater risk for hip fracture than those who do not.
• Smokers are more apt to develop degenerative disorders and injuries in the spine.
• Smokers have more trouble recovering from surgeries, including knee or hip replacements.
• Smokers whose jobs involve lifting heavy objects are more likely to develop low back pain than nonsmokers.
• Smoking may increase the risk of rheumatoid arthritis in some older women. A 2006 study in Annals of the Rheumatic Diseases showed that smoking nearly doubled the risk of rheumatoid arthritis in postmenopausal women who did not have the most established genetic risk factor for the disease, a genotype called HLA-DRB1 SE.

Smoking and Diabetes

Smoking may increase the risk of developing diabetes. Researchers involved in the Insulin Resistance Atherosclerosis Study (IRAS) looked at the relationship between smoking and diabetes and found that 25% of smokers who started the trial with normal blood sugar had diabetes 5 years later compared to 14% of non-smokers. The results were published in Diabetes Care.

A study released in 2006 supports earlier beliefs that smokers have a higher risk of developing glucose intolerance, a condition that precedes diabetes. The study, published in the British Medical Journal, involved 4,572 people. The findings suggest that chemicals in smoke could affect the pancreas. The pancreas is the organ that produces insulin, which helps control blood sugar (glucose) levels.

Smoking and the Gastrointestinal Tract

Smoking increases acid production in the stomach. It also reduces blood flow and production of compounds that protect the stomach lining.

Diverticulitis. A 2000 study suggested that smoking was a major risk factor in diverticulitis, a condition in which small bumps develop in the wall of the colon. In addition, smokers were at risk for complications from diverticulitis, including bleeding and abscess. Diverticulitis mostly affects people over age 50.

Reviewed By: Harvey Simon, MD, Editor-in-Chief, Associate Professor of Medicine, Harvard Medical School; Physician, Massachusetts General Hospital