12 Reasons to Really Quit Smoking

Video: Secrets to a Better You: How to Stop Smoking for Good

Heightened susceptibility to infections, it appears, isn't limited just to those who do the smoking: A May study in Tobacco Control found that children exposed to secondhand smoke at home during early infancy (especially those born prematurely or with a low birth weight) are more prone to a throng of severe illnesses that may land them in the hospital at some point during childhood. The findings were based on an analysis of more than 7,000 Chinese children from 1997 to 2005.

4. It may stultify a sex life. If men want to hop aboard the Viagra bandwagon, mounting evidence suggests that puffing cigarettes might be just their ticket. Smokers are more apt to experience erectile dysfunction than nonsmokers are, and this risk climbs as the number of cigarettes smoked increases. A study in the American Journal of Epidemiology in 2007 tracked more than 7,500 Chinese men with low risk for artherosclerosis, a chief underlying cause of erectile dysfunction, and found that smoking could independently hike a man's chance of wrangling with the sexual condition. Preventing smoking is an "important approach" for cutting the risk of ED, the researchers concluded.

5. It may lead to wrinkles...everywhere. Not only does smoking contribute to premature facial wrinkles, but a 2007 study in the Archives of Dermatology found that it may also lead to wrinkling of skin that rarely sees the light of day—in areas such as the inner arm and perhaps the buttocks.

6. It may hasten menopause. Women who smoke face an increased risk of infertility, and they may experience natural menopause at a younger age than do nonsmokers, according to the 2004 and the 2001 Surgeon General's Reports, respectively. Further evidence: A 2001 animal study in Nature Genetics found that chemicals in cigarette smoke can hurry menopause by killing off egg cells made by ovaries, thereby dwindling the egg cell reserve. Since the timing of menopause is dictated by the size of a woman's egg cell reserve—which is stocked with about a million eggs at birth and vanishes by menopause—anything that speeds up its loss could logically lead to a much earlier onset of fertility troubles, notes Jonathan Tilly, one of the study's authors and director of the Vincent Center for Reproductive Biology at Massachusetts General Hospital. More worrisome: Women who smoke during pregnancy may be compromising not only their own future fertility but the fertility of their unborn daughters. In studies testing that idea, mice exposed to chemicals in cigarette smoke during gestation were born with shrunken egg reserves. "Even under the best-chance scenario—you're a nonsmoker, you're healthy, you're young, you eat well, you're in shape—human fertility isn't 100 percent," says Tilly. "Anything you can do to make it better is certainly worth your while."

7. It may dull vision. Several studies have found a robust link between smoking and eye disease, specifically age-related macular degeneration, which can permanently blur vision or cause blindness. A 2005 review of 17 studies in the journal Eye reported that active smokers may face two to three times the risk for developing the disease experienced by those who have never smoked.