Health Risks

Smoking -- even just a few cigarettes a day -- has been linked to many serious health risks. Some are listed below.

Effects on the Lungs

According to the American Lung Association, smoking is directly responsible for about 90% 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.

Cardiovascular Effects

All forms of tobacco raise the risk of heart attacks. Smoking, chewing tobacco, and being exposed to secondhand smoke greatly increase the risk of a heart attack. In some cases, the risk of heart problems in people who smoke or are exposed to smoke may be three times greater. The risk of a heart attack among those who stopped smoking may slowly decrease over time.

Effects on Male Fertility and Erectile Dysfunction

Smoking can harm a man's sexuality and fertility. Heavy smoking is frequently cited as a contributory factor in erectile dysfunction because it decreases the amount of blood flowing into the penis.

Smoking impairs sperm motility, reduces sperm lifespan, and may cause genetic changes that can affect a man's offspring. One 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 Female Infertility, Pregnancy, and Childbirth

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 the Unborn Child. Smoking during pregnancy increases the risk for stillbirth, prematurity, and low birth weight in their babies. Women who smoke during pregnancy have lower levels of folate, a B vitamin that is important for preventing birth defects.

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

A new study published in July 2008 found a definite connection between smoking in the first trimester of pregnancy and an increased risk of having a baby with cleft lip (a split lip that has not closed during the fetus' development).