Quitting smoking pays off in diabetes care: fewer eye, kidney and nerve problems
☕ Includes a question for the family ↓
Tools for living with diabetesPart of a story we are following · 3 articles · See every update
If you have diabetes and smoke, here is a reason to pick a quit date. Quitting is a real part of diabetes care, and a large study found the payoff keeps growing the longer you stay smoke-free.
People with type 2 diabetes who quit and stayed quit for 8 or more years had a lower risk of eye, kidney and nerve damage than people who kept smoking. It takes time, and it is worth it. The clock starts the day you stop.
How the study worked
Researchers used South Korea’s national health records for a large group of adults first diagnosed with type 2 diabetes between 2003 and 2013, checked their smoking status at least 4 times at health checkups, and compared people who quit and stayed quit (grouped by how long they had been smoke-free) with people who smoked at every checkup. The results were published Oct. 1, 2026, in JAMA Network Open; because it is an observational study, it shows a strong link, and complications were identified from medical diagnosis codes.
What they found
After 8 or more smoke-free years, quitters had a lower risk than continuing smokers of:
- any small-vessel complication of diabetes
- kidney damage
- eye damage
- nerve damage
The biggest gap showed up in eye damage. People who had been smoke-free for 6 to 7 years already had a lower risk of nerve damage, so some benefits start to appear before the 8-year mark.
The links showed up mainly among men. Few women in the study smoked, which may explain why.
Why do small blood vessels matter?
Over time, diabetes can wear down the tiniest blood vessels in your body. Those vessels feed your kidneys, your eyes and your nerves. When they are damaged, the result can be kidney disease, vision problems and numbness or pain in the feet and hands.
Smoking adds to that strain. Quitting takes some of it away, and this study suggests the relief builds year after year.
What you can do today
Pick a quit date in the next two weeks and write it on your calendar. Then tell one person who can cheer you on. Your doctor or pharmacist can walk you through options such as nicotine replacement, quit-smoking medicines and quitlines, so you do not have to do it on willpower alone. Keep up your yearly eye exam, kidney tests and foot checks as you go. Choose the date now.
Talk about it at home
Your body has tiny tubes, thinner than a hair, that carry blood to your eyes, kidneys and nerves. Diabetes can wear them down, and smoking makes it worse. People who quit and stayed quit for many years had fewer problems with those parts of the body.
Question for the table
How do you think scientists could tell that quitting helped, and not just that people who quit were also doing other healthy things?
Keep exploring
Copies this article and its questions so you can paste them into ChatGPT, Claude, Gemini or the AI you use, and keep the conversation going.
Questions and answers
- What are microvascular complications?
- They are damage to the smallest blood vessels caused by diabetes, which can harm the kidneys, eyes and nerves.
- How long did people need to be smoke-free to see a benefit?
- In this study, 8 or more years went with lower risk of kidney, eye and nerve damage. Nerve damage risk was already lower at 6 to 7 years.
- Did the results apply to women too?
- The links showed up mainly among men. Few women in the study smoked, which may explain it.
- Does quitting help even after years of smoking?
- The study looked at people who were smoking at their first checkup and then quit. Those who stayed quit had lower risk over time.
