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.
8. It hurts bones. Smoking weakens the body's scaffolding and is a serious risk factor for osteoporosis, according to the National Institute of Arthritis and Musculoskeletal and Skin Diseases. It's been shown to fritter away bone density in postmenopausal women and to hike the risk of hip fractures in both sexes, according to the 2004 Surgeon General's Report. (People who endure hip fractures are 12 to 20 percent more likely to die than those who don't, the Report notes, though there are ways osteoporosis sufferers can protect themselves.) Smokers may also experience slower healing of broken bones and wounded tissues than do nonsmokers.
9. It may injure the insides. Sure, cigarettes may be smooth to inhale, but they can rough up the digestive system, leading to heartburn, peptic ulcers, and possibly gallstones, according to the National Institute of Diabetes and Digestive and Kidney Diseases. What's more, current and former smokers have an elevated risk of developing Crohn's disease, a condition characterized by inflammation in the digestive tract and causing pain and diarrhea, says NIDDK.
10. It may stifle sleep. Feeling groggy despite a night's slumber might be a problem for those who light up: A February study in Chest found that smokers are four times more likely to get nonrestorative sleep than those who don't smoke, and researchers deemed nicotine the likely culprit. They theorized that its stimulant properties deal smokers a double blow, making it difficult to fall asleep and also potentially sending the body into nicotine withdrawal during the night. (Half of the chemical's effect wears off within two hours.) Since inadequate shut-eye can invite health problems, consider forgoing cigarettes for the sake of your sleep.
11. It shaves years—and quality—off life. Men who have never smoked live on average 10 years longer than their peers who smoke heavily, according to an October report in the Archives of Internal Medicine. Moreover, they enjoyed a higher quality of life throughout those extra years, throwing sand in the face of the old smokers' defense that an early death is a small price to pay for a lifetime of pleasure. The study's Finnish authors drew their conclusion after scrutinizing data on more than 1,600 men tracked for nearly 30 years.