10 Overlooked Reasons to Quit Smoking

You know smoking causes lung cancer, emphysema, and heart disease, but you're still lighting up. To help you get on the wagon, we've compiled a list of little known ways your life can go up in smoke if you don't kick the habit.

From an increased risk of blindness to a faster decline in mental function, here are 10 compelling -- and often surprising -- reasons to stick to your commitment. And so you don't have to go it alone, we've also put together a step-by-step guide on how to use WebMD Resources to get started. No butts about it!

Alzheimer's Disease: Smoking Speeds Up Mental Decline

In the elderly years, the rate of mental decline is up to five times faster in smokers than in nonsmokers, according to a study of 9,200 men and women over age 65.

Participants took standardized tests used to detect mental impairment when they entered the study and again two years later. Higher rates of mental decline were found in men and women -- and in persons with or without a family history of dementia or Alzheimer's disease, the researchers reported in the March issue of the journal Neurology.

Smoking likely puts into effect a vicious cycle of artery damage, clotting and increased risk of stroke, causing mental decline, writes researcher A. Ott, MD, a medical microbiologist with Erasmus University Medical Centre in the Netherlands.

The bottom line: The study provides substantial evidence that chronic tobacco use is harmful to the brain and speeds up onset of Alzheimer's disease, Ott says.

Lupus: Smoking Raises Risk of Autoimmune Disease

Smoking cigarettes raises the risk of developing lupus -- but quitting cuts that risk, an analysis of nine studies shows.

Systemic lupus erythematosus -- known as lupus -- is a chronic autoimmune disease that can cause inflammation, pain, and tissue damage throughout the body. Although some people with lupus have mild symptoms, it can become quite severe.

For the analysis, Harvard researchers reviewed studies that examined the relationship between cigarette smoking and lupus. Among current smokers, there was "a small but significant increased risk" for the development of lupus, they report. Former smokers did not have this increased risk, according to the study, which appeared in the March issue of Arthritis & Rheumatism.

SIDS: Maternal Smoking Doubles Risk

Smoking increases the risk of sudden infant death syndrome, or SIDS, a European analysis shows.

The researchers compared 745 SIDS cases with more than 2,400 live babies for comparison and concluded that just under half of all deaths were attributable to infants sleeping on their stomachs or sides. Roughly 16% of SIDS deaths were linked to bed sharing, but for unknown reasons, bed sharing was particularly risky when the mother smoked. The risk was very small when mothers did not smoke during pregnancy, the researchers say.

Maternal smoking alone was associated with a doubling in SIDS risk. The risk was 17 times greater, however, for babies who bed shared and had mothers who smoked. The findings are reported in the Jan. 17 issue of The Lancet.

"The safest thing to do is to put the baby to bed on his back with no bedcovers in the same room with parents who don't smoke," London School of Hygiene and Tropical Medicine epidemiologist Robert G. Carpenter, PhD, tells WebMD.

Colic: Smoking Makes Babies Irritable, Too

Exposure to tobacco smoke may increase babies' risk of colic, according to a review of more than 30 studies on the topic.

Colic often starts a few weeks after birth, peaking at about 5 to 8 weeks of age. It usually goes away by 4 months of age. Babies' symptoms include irritability, inconsolable crying, red face, clenched fists, drawn-up legs, and screaming.

Colic affects an estimated 5%-28% of babies born in Western countries. Its causes have been attributed to everything from exposure to cow's milk proteins to feeding difficulties to maternal depression or anxiety.

Tobacco smoke appears to raise levels of a gut hormone called motilin in the blood and intestines. Motilin increases the contractions of the stomach and intestines, increasing the movement of food through the gut. "Higher-than-average motilin levels are linked to elevated risks of infantile colic," the researchers write in the October issue of the journal Pediatrics.

An Increased Risk of Impotence

Guys concerned about their performance in the bedroom should stop lighting up, suggests a study that linked smoking to a man's ability to get an erection. The study of nearly 5,000 Chinese men showed that men who smoked more than a pack a day were 60% more likely to suffer erectile dysfunction, compared with men who never smoked cigarettes.

Overall, 15% of past and present smokers had experienced erectile dysfunction, more commonly known as impotence. Among men who had never smoked, 12% had erection problems, according to the study, presented last year at the American Heart Association's annual Conference on Cardiovascular Disease Epidemiology and Prevention in Miami.