According to a new study, conducted on over 28,000 people, daily cigarette smoking can reduce the size of your brain.
Previously, scientists had found that smokers tended to have smaller brains than non-smokers in terms of volume, but they were unable to clarify whether smoking causes the brain to shrink or if people with smaller brains were more likely to take up the habit.
In this new report, published in medRxiv, researchers have found strong evidence that smoking can cause brain shrinkage.
Brain imaging data showed differences in brain sizes
The study was conducted using brain imaging data from the UK Biobank, a large repository of genetic and health data from UK-based participants and then combined the imaging data with the participants’ self-reported smoking habits, collected in surveys.
The surveys were taken twice – once between 2006 and 2010 and then again between 2012 and 2013. In the same time window, participants’ brains were also scanned using MRIs.
Researchers found that compared to people that have never had a daily smoking habit, those who smoked on a daily basis prior to brain imaging had brain volumes that were 0.4 cubic inches (7.1 cubic centimetres) smaller, on average
Researchers also found that those who had previously smoked more heavily showed larger differences in grey matter – which is responsible for processing sensation, perception, voluntary movement, learning, speech, and cognition – than previous scans.
Each additional “pack year” smoked — a measure equivalent to smoking one pack a day for one year — was linked to a roughly 0.01-cubic-inch (0.15 cc) decrease in grey matter volume, on average.
According to researchers, this supports the idea that smoking causes reduction in brain size
Quitting smoking can reverse “shrinking” effects
It’s not all bad news for smokers, though. Further analysis by the researchers found that for people who had quit smoking for longer, they had slightly more grey matter than those who had quit more recently. The researchers believe that this suggests stopping smoking can reverse the decline in brain volume.
Finally, researchers looked at gene variants to see if the genes that influence smoking risk might too be linked to differences in grey matter volume. While they found that people with a higher genetic risk were more likely to have smoked in the past, their genetics in isolation weren’t tied to grey matter volume.
They found that a history of daily smoking was tied to grey matter volume, supporting their theory that smoking drives the changes in brain sizes.
Brain shrinking symptoms
Brain shrinking or as it’s known in the medical world, cerebral atrophy, is relatively normal over decades of time and especially in older people who may still be otherwise cognitively healthy. According to the National Institute of Neurological Disorders and Stroke, cerebral atrophy symptoms can include:
- Dementia
- Disorientation
- Seizures
- Difficulty communicating
- Memory loss
- Loss of coordination
- Localised weakness, loss of sensation, or paralysis
- Blurred or double vision
- Disturbances in speaking and understanding language
How to quit smoking
It goes without saying that smoking is bad for your health but of course, that doesn’t always make quitting easier. According to the NHS, there are plenty of NHS services to help you along the way when it comes to stopping smoking. These can include:
- One-to-one and group stop smoking sessions
- Nicotine replacement therapy like patches and gum
- Bupropion - an antidepressant medication that is also used to help stop smoking