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Published on October 26, 2021

Smoking in midlife raises your risk of dementia by over 150 percent

Smoking and Dementia

In addition to causing cancer, particularly of the lungs, smoking can also lead to heart disease and be devastating to the brain. A study published last fall in the Archives of Internal Medicine showed that heavy smoking in midlife increased the risk of Alzheimer’s disease and vascular dementia by over 150 percent.

The study of over 21,000 people was conducted between 1978 and 1985. Participants were then followed for 23 years. The results showed that people who smoked two packs of cigarettes a day in middle age had an increased risk of 157 percent for Alzheimer’s and of 172 percent for vascular dementia.

“It’s legit,” said Neurologist Sean Horrigan, DO at Neurologists of Cape Cod in Hyannis. “Smoking is linked with multiple health hazards. It has been so well studied for so many years. When it comes to promoting brain health and protecting cognitive performance, it’s a fact that smokers are at a much higher risk for dementia as well as suffering a stroke in their lifetime.”

Yet, while the percentage of smokers has dropped from 20.9 percent in 2005 to 14 percent in 2019, there are still 34.1 million Americans who regularly smoke cigarettes, according to the CDC. Sixteen million Americans live with smoking-related diseases and smoking accounts for one in five deaths in the U.S.

The association between smoking and stroke has a lot to do with vascular health, Dr. Horrigan said. “Your brain is only as good as the blood vessels feeding it.” 

If the blood vessels are inflamed by smoking, it causes your vascular health to decline, he added. That in turn causes poor blood circulation, atherosclerotic disease and, eventually, organ shutdown. Poor vascular health speeds up the Alzheimer’s process. People who smoke begin showing signs of Alzheimer’s at an earlier age and progress with the disease more rapidly.

Smoking tobacco also increases a person’s blood platelet count, which then thickens the blood, Dr. Horrigan said. Cigarettes also have many direct toxic compounds that can accelerate atherosclerosis. Once you start to get artery damage, every organ that the arteries feed suffers because of poor circulation, which can eventually lead to a heart attack or stroke. Having a stroke then also increases the risk of vascular dementia, he said.

Patients with vascular dementia decline in a different way than Alzheimer’s patients, he said. He described the typical decline of an Alzheimer’s patient as a gradual slope downward. Whereas, patients with vascular dementia tend to decline in a more staircase manner, meaning they will stay stable for a while and then take a big step down all at once. The cause of this bigger step could be a stroke, or another decline in vascular health.

Another harmful and debilitating disease caused by smoking is COPD, a lung disease where the patient has a compromised ability to get adequate oxygen. When the brain doesn’t get enough oxygen, it performs poorly.

“The human brain is an especially sensitive organ,” Dr. Horrigan said. “It really needs the appropriate amount of oxygen and nutrition on a second-to-second basis. If you starve the brain of O2, it’s obviously not going to perform its best.”

Other Health Benefits to Quitting

Fortunately, if you do smoke, there are plenty of health benefits if you quit, especially if you do it at a younger age. A study of just over 113,00 done by Jennifer Deal, assistant professor of epidemiology at Johns Hopkins Bloomberg School of Public Health in Baltimore, indicated that the average smoker’s increased risk for dementia decreases over time if they quit.

Decreasing the risk of dementia is far from the only benefit of quitting smoking. Dr. Horrigan shared a chart put out by the World Health Organization showing the effects of quitting smoking and the improvements and time required to get back to a healthier life.

Those effects include:

  • 20 minutes after your last cigarette, your heart rate and blood pressure drop.
  • 12 hours after your last cigarette, the carbon monoxide level in your blood drops to normal.
  • 2 to 12 weeks after your last cigarette, your circulation improves and lung function increases.
  • 1 to 9 months after your last cigarette, coughing and shortness of breath decreases.
  • 1 year after your last cigarette, your risk of coronary heart disease is half that of a smoker.
  • 5 to 15 years after your last cigarette, your risk of stroke is reduced to that of a nonsmoker.
  • 10 years after your last cigarette, your risk of lung cancer is cut in half.
  • 15 years after your last cigarette, your risk of coronary heart disease is reduced to the level of a person who never smoked.

If you are interested in quitting smoking, talk to your doctor about safe nicotine replacements like gum, lozenges, patches and prescription drugs that can quell the urge to smoke. You can also visit for more information.

They offer a quit plan, tips on the best ways to quit and smoke-free apps and text messaging that offers 24/7 support and encouragement. They also offer the chance to speak with experienced smoking cessation counselors who will help you make a plan to succeed if you call 1-800-QUIT-NOW. You can even sign up to participate in a research study that might help other people quit in the future.

“It surprises me that there are so many Americans that continue to smoke,” Dr. Horrigan said. “The numbers have gotten better and you’d think with all the knowledge out there it would be close to zero, but it’s not.”