More research has been published linking smoking to health risks - with a study suggesting the habit affects IQ
Researchers from the Universities of Aberdeen and Edinburgh looked at how the cognitive abilities of smokers and non-smokers changed over time.
They found smokers performed significantly worse in five separate tests.
The research, part of the Scottish Mental Health Survey, is published in New Scientist magazine.
It would appear that the well-worn cliché that 'smoking stunts your growth' may be true when it comes to intellectual development
Amanda Sandford, Action on Smoking and Health
They were then tested a second time between 2002 and 2002, when they reached the age of 64.
On this occasion they underwent tests to evaluate their non-verbal reasoning, memory and learning, how quickly they processed information, decisions about how to act in particular circumstances and construction tasks.
Current or former smokers were found to perform less well in the tests even after factors such as childhood IQ, education, occupation and alcohol consumption were taken into account.
The effect appeared to be stronger in current smokers according to the study, which was also published in the journal Addictive Behaviors.
The researchers suggest a "small but significant" negative effect of 4% linked to the combined effects of smoking and impaired lung function - itself linked to smoking.
It has been suggested in previous studies that there could be a link between impaired lung function and a negative effect on the thinking processes, but it is not clear what the mechanism for that might be.
Dr Lawrence Whalley of the University of Aberdeen, who led the research, said the explanation could be that smoking causes oxidative stress - cumulative damage caused by molecules called "free radicals" - to organs including the brain.
"Ageing neurons are very sensitive to oxidative damage."
Writing in Addictive Behaviors, Dr Whalley added: "The harmful effects of smoking on lung function are well established."
But he said the detrimental effect on cognition could be due to be attributable to poor heart and lung function affecting the brain, or directly harmful effects of smoking on brain - as well as lung - tissue.
Amanda Sandford, of the group Action on Smoking and Health said: "It would appear that the well-worn cliché that 'smoking stunts your growth' may be true when it comes to intellectual development.
"Contrary to what many people commonly believe - that smoking may help brain function, it is in fact more likely to wreak havoc with brain cells and IQ.
"Any teenager tempted to smoke should heed the message that it really is dumb to take up this noxious habit. " - Reference BBC News
- People may smoke to look cool. People may smoke because of peer pressure, because they want to hang out with friends who take cigarette breaks and you don't want to appear different. Or people may be unable to stop smoking because they are too addicted. Smoking has extremely negative effects, especially on a health and appearance. Smoking affects not only the smoker, but also those in his or her proximity.Sam Diephuis / Getty Images
Smoking is Bad for Your Long-term Health
- The U.S. Centers for Disease Control and Prevention says smoking is the leading cause of fatal lung disease and can also lead to various cancers, coronary heart disease, strokes and reduced blood circulation.
Smoking is Hazardous to Other People's Long-term Health
- According to the U.S. Surgeon General, breathing other people's smoke, known as secondhand smoke, can shorten a person's lifespan. Secondhand smoke also causes cancers and respiratory diseases in both children and adults. In fact, secondhand smoke often contains more cancer-causing and toxic chemicals than those found in smoke a person inhales himself.
Smoking Can Repel Non-smokers
- A non-smoker may see your smoking as off-putting. How would you feel if you were around a person who smelled terrible all the time and blew nasty-smelling air around you? A smoker may lose out on dating opportunities or chances to make new friends among non-smokers who detest the habit.
Smoking Makes You and Others Smell Bad
- Smoking makes your breath smell like an ashtray. Smoke also tends to cling to clothing. Spending time in a bar or restaurant that allows smoking in a non-ventilated area will make a person smell like an ashtray at the end of the night, even if that person did not smoke.
Smoking Can Hinder Breathing
- Smoking can make breathing difficult. Smokers often have coughing fits, even when not actually smoking. Furthermore, inhaling secondhand smoke can make breathing difficult. Furthermore, it can spark and worsen symptoms of asthma attacks in children, according to the U.S. Environmental Protection Agency.
Smoking Harms Fetuses
- Smoking can have a negative effect on a woman's unborn child. If a pregnant woman smokes during her pregnancy or inhales someone else's smoke constantly, she can pass unwanted prenatal diseases to the fetus. Kicking a smoking habit in your first trimester of a pregnancy could lower a woman's risk for delivering a preterm or small-for-gestational-age baby, a 2009 study published in the Obstetrics & Gynecology medical journal found.
Smoking Can Cause Oral Problems
- Smoking can make a person lose teeth. People with gum disease who quit smoking during their dental treatments showed more symptoms of recovery, according to a 2005 study by the University of Newcastle upon Tyne, UK.
Smoking is Bad for Your Skin
- Smoking increases a person's risk of developing wrinkles on her face. A 2008 Israeli study, published in the International Journal of Dermatology, found facial wrinkling was more likely to be seen among smokers than among nonsmokers.
Smoking Discolors Walls
- Smoke stains walls. If a smoker plans on selling your house and has smoked at home regularly, he may want to consider painting the walls.
Smoking is addictive
- It is difficult to quit smoking. Nicotine is a addictive drug and quitting it can lead to unpleasant symptoms of withdrawal. Smokers who have recently kicked the habit are often irritable or angry, may shake a lot and get headaches.
• Lung Cancer
• Heart Diseases
• High Blood Pressure
• Bad Breath
• Gum Disease
• Infertility on men and women
• Thyroid Disease
• Harmful effects on Bones and Joints