Updated 26 August 2013

Smoking: what you don’t know

Yes, we know you know: smoking ups risk for lung cancer and heart disease. But cot death? Damaged sperm? Tobacco use is a total onslaught on you and yours.


Yes, we know you know: smoking ups risk for lung cancer and heart disease. But cot death? Damaged sperm? Tobacco use is a total onslaught on you and yours.

Each new study makes it more apparent that smoking harms just about every tissue in the body, and in the bodies of those in a smoker’s presence. It may even harm your yet-to-be-conceived children. The following are some of the most important findings from recent research on the effects of tobacco use:

Smoking dads may pass on damaged genes
Children could inherit genetic damage if their father is (or has been) a smoker.

In an experiment on mice, Canadian researchers demonstrated that smoking can cause mutations in the DNA of sperm cells, irreversible changes that could potentially be inherited by offspring.

“We have known that mothers who smoke can harm their foetuses, and here we show evidence that fathers can potentially damage offspring long before they may even meet their future mate,” said Carole Yauk, lead author of the study.

Study findings suggested that damage is related to duration of exposure i.e. the longer you smoke, the more mutations accumulate and the more likely a potential effect may arise in your offspring.

Smokers’ sleep does not refresh
Smokers are four times as likely as non-smokers to report feeling unrested after a night’s sleep, according to a Johns Hopkins University School of Medicine study.

Smokers spend less time in deep sleep – the restorative part of the sleep cycle that aids on recovery from sleep deprivation – and more time in light sleep than non-smokers.

Researchers speculate that the stimulating effects of nicotine could cause smokers to experience nicotine withdrawal each night, which may contribute to disturbances in sleep.

Study author Naresh Punjabi from Johns Hopkins University School of Medicine: “Smokers commonly experience difficulty falling asleep due to the stimulating effects of nicotine. As night evolves, withdrawal from nicotine may further contribute to sleep disturbance.”

Nicotine tied to infant death
The risk of a baby succumbing to sudden infant death syndrome is higher when the mother smoked during pregnancy – and nicotine may be to blame, according to Canadian researchers.

Normally, a drop in oxygen in the bloodstream arouses a baby from sleep, which leads to better breathing.

During the newborn period, this is triggered by specialised cells in the adrenal gland that detect oxygen deprivation and respond by releasing the appropriate hormones to help the body adapt.

Using rats, the researchers showed that nicotine exposure can lead to a breakdown in this chain of events by impairing the ability of these specialised cells to release the appropriate hormones.

Puffing may bring on diabetes
Smokers are on average 44% more likely than non-smokers to develop type II diabetes, according to a massive Swiss study that pooled the results of 25 other studies and tracked the health of a total of 1.2 million people.

For heavy smokers the risk of developing type II diabetes is even higher. The researchers estimate that smoking 20 or more cigarettes a day result in a 61% higher risk than that of non-smokers.

On the positive side though, the researchers found that quitting does indeed make a difference. Apparently, former smokers only have a 23% higher risk than non-smokers – which is well below the 44% increased risk for the average smoker.

Smokers more vulnerable to TB
If all of the above isn't scary enough, smoking has also been associated with an increased risk of developing tuberculosis. And not only does it increase the risk of infection, it also ups the odds of actually getting sick, says a team of US researchers.

They estimate that smokers are at a 73% higher risk of infection than non-smokers. Once infected, the chances of actually getting active TB disease is 50% higher than what it is for non-smoking people who are infected.

Add it all up, and smokers are 2.5 times more likely than non-smokers going down that terrible road from being clean to struggling with activeTB.

Compiled by Marcus Low and Olivia Rose-Innes, Health24, May 2008

Smoking damages sperm: EurekAlert, June 2007
Smokers don’t sleep well, EurekAlert, February 2008
Smoking increases TB risk, January 2008, Archives of Internal Medicine
More clues to smoking-SIDS link, February 2008, Reuters Health
Smoking tied to diabetes, December 2007, Reuters Health


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