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One in ten cigarette smokers in their 40s experience cognitive decline

Smoking cigarettes can cause a person to experience cognitive decline in their 40s, according to a study.

A study of 136,018 participants over age 45 by an Ohio State University (OSU) team found that 10% of middle-aged or older smokers suffered from memory loss and confusion. Overall, smokers were twice as likely to have brain problems as their peers.

Kicking the bad habit can stop the decline. Former smokers who quit more than 10 years ago had a 50% higher risk of brain problems – half the risk of current smokers.

Cognitive problems are rare in middle-aged people, as the brain doesn’t start to lose function until after age 65 in most cases. Smoking has been linked to many significant health issues later in life, such as Alzheimer’s and cancer, among others. Women are also more likely to experience cognitive decline than men.

Researchers have found that smoking can cause cognitive decline in people as young as 45 (file photo)

Researchers have found that smoking can cause cognitive decline in people as young as 45 (file photo)

Smoking has been linked to an increased risk of developing cognitive conditions such as Alzheimer’s disease, but presentation of these problems in middle-aged people is rare.

For their research, published in the Journal of Alzheimer’s Disease, researchers surveyed a sample of nearly 140,000 people about their smoking habits and whether they felt they experienced memory loss during that time.

They found that 8% of people who had never smoked in their lifetime experienced cognitive decline.

Meanwhile, 16% of current smokers reported brain problems and memory loss.

Many of these smokers were too young to be dealing with these problems.

Just under 10% of participants aged between 45 and 49 reported brain problems when surveyed – with the researchers noting that nearly all were smokers.

The rate of reported cognitive problems was similar among survey participants in their fifties.

Differences in cognitive decline between smokers and non-smokers greatly diminish in old age, as at this point many people develop conditions like Alzheimer’s and dementia for a variety of reasons.

What is Alzheimer’s?

Alzheimer’s disease is a progressive, degenerative disease of the brain in which abnormal protein buildup causes nerve cell death.

This disrupts the transmitters that transmit messages and causes the brain to shrink.

More than 5 million people suffer from the disease in the United States, where it is the 6th leading cause of death, and more than 1 million Britons have it.


As brain cells die, the functions they provide are lost.

This includes memory, orientation, and the ability to think and reason.

Disease progress is slow and gradual.

On average, patients live five to seven years after diagnosis, but some can live ten to 15 years.


  • short term memory loss
  • disorientation
  • behavioral changes
  • mood swings
  • Difficulties handling money or making a phone call


  • Severe memory loss, forgetting close family members, familiar objects or places
  • Becoming anxious and frustrated with an inability to make sense of the world, leading to aggressive behavior
  • Eventually lose the ability to walk
  • May have trouble eating
  • Most will eventually need round-the-clock care

Source: Alzheimer’s Association


“The association we saw was most significant in the 45-59 age group, suggesting that stopping at this stage in life may have benefits for cognitive health,” said Jeffrey Wing, senior author of the study and professor of epidemiology at OSU.

Quitting smoking can undo some of the damage, however. About 12% of survey participants who quit more than a decade ago reported cognitive problems.

This is still a 50% increase over the baseline group of non-smokers, a significant decrease compared to non-smokers.

People who quit smoking in the last 10 years had a 13% risk of developing the disease, slightly higher than those who quit for a long time.

“These findings may imply that time since smoking cessation is important and may be linked to cognitive outcomes,” said Jenna Rajczyk, an OSU doctoral student who led the research.

“This is a simple assessment that can easily be done routinely, and at younger ages than usual we start to see cognitive declines that reach the level of a diagnosis of Alzheimer’s disease or dementia,” she continued.

‘It’s not an intensive battery of questions. It’s more of a personal reflection of your cognitive state to determine if you feel you’re not as sharp as you used to be.’

The study only took self-reported examples of cognitive problems and did not collect any data on clinical diagnosis of Alzheimer’s or dementia.

Signs of the devastating condition often begin to emerge decades before the patient is ready to receive a diagnosis, and it is rare for a middle-aged person to be told by a doctor that they have the disease.

Alzheimer’s disease is the leading cause of dementia in the United States. It affects an estimated 6.5 million Americans age 65 and older.

The number of Americans suffering from the disease is expected to double over the next 20 years, as longer life expectancy will lead to more cases over time.

There is no known cure for the disease, and treatments available to slow the progression of the disease are scarce.