Diabetes and smoking

Key points about diabetes and smoking

  • Smoking causes health problems in everyone who smokes, but if you have diabetes it can be even more damaging to your health.
  • Quitting smoking helps get your blood glucose level down and reduce your health risks.
  • It's not easy to quit, but you'll be glad you did. It is the thing shown to make the biggest positive impact on your health.
  • The sooner you quit, the more your health will benefit. 
  • Cutting down smoking is not the same as stoping completely.
  • There is support available to help you quit smoking.
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Smoking and diabetes both increase the risk of heart disease in similar ways. This means that when combined they greatly increase your chance of developing a heart-related condition such as a heart attack or stroke.  

High levels of glucose in your blood and smoking both damage the walls of your arteries (blood vessels) in a way that means fatty deposits (plaque) can build up much easier. This is known as atherosclerosis. As atherosclerosis occurs, your blood vessels narrow and therefore blood (and vital oxygen) flows through less easily.

When this happens to your coronary arteries (the arteries that supply the heart muscle with blood) you can have a heart attack or angina. When this happens to the arteries that take blood to your brain, you can have a stroke.

In the same way, both smoking and diabetes affect blood vessels in other parts of your body, so adding both together really increases your risk of conditions linked to poor blood circulation.

With diabetes, if you have high blood glucose levels over several years, your blood vessels can become damaged. This can lead to plaque forming in your blood vessels and make it harder for them to deliver enough blood to your cells.

Smoking slows down circulation in the smaller blood vessels that supply your hands and feet.

Poor circulation increases your risk of:

Diabetes can increase your risk of sight problems by damaging the small blood vessels that take blood and oxygen to your eyes. Eye conditions in diabetes include diabetic retinopathy,cataract and glaucoma. Smoking may add to blood vessel damage in your eyes and also cause different eye problems such as age-related macular degeneration. These eye conditions can lead to blindness. Read more about diabetes and eye problems

Raised blood glucose in diabetes can also damage the blood vessels in your kidneys. About 1 in 3 people with diabetes will end up with some kidney damage. Diabetic kidney disease is also called diabetic nephropathy.

If you smoke, you further increase your risk of kidney disease as it also damages your blood vessel walls.

Erectile dysfunction is the inability to get or maintain an erection firm enough for sex. This is common in men who have diabetes, especially those with type 2 diabetes. It can stem from damage to your nerves and blood vessels caused by poor long-term high blood glucose levels.

Men with diabetes who smoke are even more likely to have erection problems. When you smoke, chemicals from the cigarette can interfere with the blood flow to your penis and damage the lining of the blood vessels or lead to atherosclerosis (hardening of the arteries). It can also affect the smooth muscle tissue that needs to relax to allow blood to flow in. Nerve damage may also reduce sensation. 

How does smoking affect my joints when I have diabetes?

Movement and flexibility in your joints may be affected by smoking when you have diabetes.

How does smoking affect my nerves when I have diabetes?

Smoking will increase the risk of nerve damage in all parts of your body, leading to numbness and pain. This is on top of the risk of nerve damage caused by diabetes. Read more about diabetes and nerve damage.

If you smoke you have a higher chance of getting gum disease and losing your teeth.

Smoking raises your blood glucose level, making it harder to control your diabetes. Quitting smoking helps get your blood glucose level down. It can come down to the same level as people who have never smoked.

Stopping smoking reduces your risk of developing a major diabetes-related complication. Some people with diabetes don't quit smoking because of concerns over weight gain. However, studies have found that the benefits of giving up smoking for someone with diabetes outweigh any negative effects caused by weight gain.

It can be a challenge to quit smoking, but you'll be glad you've done it. As well as reducing your risk of diabetes complications, quitting smoking improves the quality of your life, your immune system and your level of wellbeing. You will save money too!  

The sooner you quit, the more your health will benefit.  Cutting down smoking does not change the major health risks so aim to stop completely.

The good thing is there is a lot of support and different treatment available to help you. Start by talking to your doctor about what might work best for you. Read more about quitting smoking

The following links provide further information about diabetes and smoking. Be aware that websites from other countries may have information that differs from New Zealand recommendations.

Diabetes and smoking(external link) Diabetes UK
Smoking and diabetes Quit Victoria, Australia 
Smoking and diabetes(external link) Centre for Disease Control and Prevention, US
How does smoking harm us and what’s in a cigarette?(external link) Health Promotion Agency, NZ


Diabetes poster [PDF, 349 KB] Ministry of Health and Diabetes Project Trust, NZ, 2014
Quit smoking(external link) Heart Foundation, NZ, 2018 English(external link), Chinese(external link), Hindi(external link), Korean(external link), Māori(external link), Samoan(external link), Tongan(external link), Order copies(external link)
Becoming smokefree(external link) Quitline, NZ, 2021
Te mutu tātou – bi-lingual booklet to help Māori smokers quit (external link)Quitline, NZ, 2021
Time to quit brochure(external link) Health Education, NZ, 2021
I quit smoking for baby and me(external link) Quitline, NZ, 2021


  1. Smoking and diabetes(external link) Centers for Disease Control and Prevention (CDC), US

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Credits: Healthify editorial team. Healthify is brought to you by Health Navigator Charitable Trust.

Reviewed by: Dr Alice Miller, FRNZCGP, Wellington

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