Written by Dr. Matthew Capozzi, DPM, FACFAS, CWS (board-certified foot surgeon and wound specialist) · Medically reviewed by the CircuFiber Scientific Advisory Board · Updated: October 27, 2026

Yes. Smoking increases the risk of developing type 2 diabetes, and people who smoke are 30–40% more likely to develop it than people who do not. Nicotine and other chemicals in tobacco smoke make the body's cells less responsive to insulin, raise blood sugar, and promote abdominal fat, all of which push the body toward insulin resistance. For people who already have diabetes, smoking makes blood sugar harder to control and raises the risk of heart, kidney, nerve and circulation complications. Quitting reverses much of that added risk over time.

Key Takeaways

• Smoking is an independent risk factor for type 2 diabetes. According to the Centers for Disease Control and Prevention (CDC), smokers are 30–40% more likely to develop type 2 diabetes than non-smokers, and the risk rises with the number of cigarettes smoked.
• Smoking causes insulin resistance. Nicotine from tobacco smoke makes cells less able to use insulin properly, which disrupts blood sugar regulation; smoking also promotes abdominal obesity and non-alcoholic fatty liver disease, which worsen insulin resistance further.
• Smoking makes existing diabetes worse. It raises HbA1c, and it accelerates the cardiovascular, kidney, nerve and circulation complications of diabetes.
• Quitting helps, even with a short-term bump in risk. Former smokers can see a temporary rise in diabetes risk and some weight gain in the first years after quitting, but long-term glycemic control improves and the risk of complications and death falls.
• Proven quit tools work for people with diabetes: nicotine replacement therapy, prescription medication and counseling, ideally combined and coordinated with your diabetes care team.
• Secondhand smoke and smokeless tobacco have also been associated with a higher risk of type 2 diabetes.

Does smoking increase the risk of type 2 diabetes?

Smoking increases the risk of type 2 diabetes, and the relationship is now considered causal rather than a coincidence. Smoking has been widely identified as a leading cause of many chronic conditions, such as heart disease and cancer. Cigarette smoking is highly hazardous to our health. Research shows that smokers have an increased risk for type 2 diabetes compared to non-smokers. Scientists estimate that cigarette smoking accounts for at least 25 million cases of type 2 diabetes around the world, a truly staggering figure.

The CDC puts the individual risk in plain terms: people who smoke cigarettes are 30–40% more likely to develop type 2 diabetes than people who do not, and the more cigarettes a person smokes, the higher the risk. This grave statistic highlights why quitting smoking belongs in any conversation about preventing and managing type 2 diabetes. Smoking sits alongside excess weight, inactivity and poor diet as one of the controllable risk factors for diabetes.

How does smoking cause diabetes?

Smoking causes diabetes mainly by creating insulin resistance: the chemicals in tobacco smoke damage cells so that they respond poorly to insulin, and blood sugar rises as a result. Smoking also changes where the body stores fat and stresses the liver, which compound the problem.

Harm to body cells and insulin signaling

Smoking heightens the risk of type 2 diabetes by impairing insulin sensitivity, negatively impacting Ser636 phosphorylation of IRS-1 and reducing PPAR expression, both of which are involved in controlling glucose levels. This damage to cells leaves the body unable to regulate blood sugar properly, which raises the likelihood of developing diabetes. (See how sugar intake affects diabetes risk for the dietary side of the same problem.)

Cigarette smoking is also independently linked with non-alcoholic fatty liver disease (NAFLD), another factor that intensifies existing insulin resistance and raises the chances of diabetes developing even further.

Nicotine and insulin resistance

Nicotine from tobacco smoke makes the body's cells unable to use insulin properly, which disrupts regulation of blood sugar levels. Smoking itself can worsen abdominal obesity, which further disrupts how the body responds to and uses insulin. The end result of this increase in insulin resistance is a higher risk of developing diabetes, or of worsening pre-existing problems with blood glucose control. Our guide to insulin resistance and how to improve sensitivity explains the mechanism in more depth.

Does smoking make diabetes worse if you already have it?

Smoking makes existing diabetes worse in two ways: it raises blood sugar and HbA1c by deepening insulin resistance, and it damages the blood vessels and nerves that diabetes already puts under strain. Prolonged smoking raises HbA1c levels and deteriorates insulin resistance, which can in turn lead to serious complications of type 2 diabetes. People with diabetes who smoke are more likely to develop heart disease, kidney disease (diabetic nephropathy), eye disease and nerve damage, and because smoking constricts blood vessels it also worsens circulation problems such as cold feet with diabetes and slows the healing of foot wounds.

What happens to diabetes risk when you quit smoking?

Quitting smoking lowers your long-term risk of diabetes complications and improves blood sugar control, although diabetes risk can rise briefly in the first years after quitting. Smokers who have already been diagnosed with diabetes will find that the long-term benefits more than compensate for any initial risk. Studies show a reduction in cardiovascular issues and diabetic nephropathy once someone has quit cigarettes altogether.

Improved glycemic control

Individuals can experience better glycemic control when they quit smoking, although an increase in weight is a potential side effect. Research has demonstrated that quitting can result in improved glucose homeostasis, most likely because abstaining from cigarettes reduces insulin resistance and lowers levels of insulin secretion. Overall, even with possible weight gain, those who give up the habit are able to enjoy greater regulation of their blood sugar, which is one more reason checking your blood sugar regularly matters during a quit attempt.

Fewer diabetes complications

The benefits of quitting smoking for individuals with diabetes are undeniable. By ceasing to smoke, the risk of diabetic nephropathy falls toward that of someone who has never smoked, and studies cited in the original research found as much as a 30% decrease in all-cause mortality among people with diabetes who quit smoking compared with those who continued. Smoking cessation must be taken seriously by anyone dealing with this disease; its significance cannot be overstated.

The short-term rise in risk after quitting

Quitting smoking has been associated with a temporary rise in type 2 diabetes risk in the first few years, and some studies have reported that risk peaks around three years after quitting before declining. The main driver appears to be weight gain after quitting. The risk falls over time, and the cardiovascular and overall health gains from quitting outweigh it, so this is a reason to plan for weight management when you quit, not a reason to keep smoking. Our article on weight loss strategies for diabetes can help.

What are the best ways to quit smoking if you have diabetes?

The most effective way to quit smoking with diabetes is to combine a quit aid (nicotine replacement therapy or a prescription medication) with counseling, under the guidance of your healthcare team. People with diabetes who smoke need specialized support and advice to stop, because of the strong connection between smoking and diabetes risk. Everyone has an individual path when it comes to stopping tobacco use, so healthcare providers should carefully examine each situation and choose the methods most likely to succeed.

Nicotine replacement therapy (NRT)

Nicotine replacement therapy (NRT) can provide helpful relief from withdrawal symptoms and cravings when attempting to quit smoking. People with diabetes should first consult with their doctor before using NRT, as the treatment may have interactions with diabetes medications or other health consequences. Through close consultation between healthcare providers and patients, it is possible to use this form of cessation aid safely while working toward quitting successfully.

Medications and counseling

Using a medication like Chantix along with nicotine replacement therapy can increase the likelihood of successfully quitting smoking for people with diabetes. This medication works by reducing the positive effects a person experiences when they smoke, lessening cravings and withdrawal symptoms. It is important to consult a doctor before beginning any quit-assistance medication, as it may interfere with diabetes medicines.

Extended counseling that lasts over 10 minutes has also been found to raise the success rate of giving up cigarettes by 40–60%. By taking advantage of both medication and professional advice, smokers living with diabetes have more resources available than ever before.

Alternative smoking products

Quitting smoking completely is the goal for people with diabetes, yet some may find it difficult to do so. Products such as e-cigarettes and dissolvable tobacco are sometimes suggested for people who are unable to quit altogether, and vaping is another option some people turn to. These products are not proven safe, and investigation into their long-term health impacts is essential before any definite recommendations can be made. If you are considering them, talk to your doctor rather than switching on your own.

How can your healthcare provider help you quit?

Your healthcare provider can prescribe and monitor quit aids, refer you to counseling, and adjust your diabetes treatment as your blood sugar changes after quitting. Healthcare providers have an essential role to play in promoting smoking cessation and supporting people with diabetes through the quitting process. They are responsible for administering appropriate treatments, such as nicotine replacement therapy or other medications, and providing the necessary aid while individuals quit.

Healthcare professionals can also offer counseling and alternative forms of support to those attempting to kick the cigarette addiction. Practitioners should work closely with patients to design individual approaches to stopping smoking successfully, and continuous encouragement throughout this challenging journey is vital too.

What other lifestyle changes lower diabetes risk alongside quitting?

Quitting smoking is an important step to lower the risk of diabetes, but other lifestyle modifications help as well. These include maintaining a healthy body weight, engaging in regular physical activity, eating a balanced diet, getting adequate sleep, controlling stress levels and staying socially connected. All of these steps can lead to better outcomes for people who already have diabetes and enhance overall wellbeing by helping prevent other chronic conditions. Health promotion plays an essential role here too: encouraging individuals through positive messages may boost their motivation to make healthier decisions about daily habits. For practical plans, see our guides to preventing type 2 diabetes, managing diabetes with exercise and diet and stress management with diabetes.

Does secondhand smoke increase diabetes risk?

Secondhand smoke exposure has been associated with an increased risk of type 2 diabetes, and research has indicated that tobacco alternatives such as smokeless tobacco can also be a contributing factor in developing the condition. For people with diabetes attempting to abstain from smoking, being exposed to someone else's cigarette smoke may make quitting more difficult and put their health at stake. Individuals with diabetes should take extra measures to avoid exposure to other people's cigarettes and adhere to a healthy lifestyle regimen to reduce the chance of complications.

When should you see a doctor about smoking and diabetes?

See your doctor before you start any quit attempt if you have diabetes, so that nicotine replacement or prescription medication can be chosen safely and your diabetes medicines adjusted as your blood sugar changes. Also see your doctor if you smoke and notice early signs of diabetes such as increased thirst, frequent urination, fatigue, blurred vision or slow-healing cuts; a simple blood test can confirm or rule out diabetes. If you already have diabetes and smoke, ask for a check of your heart, kidney, eye and foot health, because smoking accelerates all of these complications.

Frequently asked questions about smoking and diabetes

How much does smoking increase your risk of diabetes?

Smoking is a major risk factor for developing type 2 diabetes, with those who smoke having a 30–40% greater likelihood of acquiring it than non-smokers, according to the CDC. The risk is dose-dependent, meaning heavier smokers face a higher risk. Prolonged smoking also raises HbA1c levels and worsens insulin resistance, which can result in serious complications in people who already have type 2 diabetes.

Does quitting smoking reduce the risk of diabetes?

In the long run, yes. Quitting smoking has been associated with a temporary rise in type 2 diabetes risk in the first few years, with some studies reporting a peak around three years after quitting, largely driven by weight gain. That risk declines over time, and former smokers end up with lower risks of heart disease, kidney disease and early death than people who keep smoking. Managing weight while quitting helps shorten the window of added risk.

Can quitting smoking reverse diabetes?

Quitting smoking does not reverse diabetes on its own, but it reduces insulin resistance and improves glycemic control, which makes diabetes easier to manage. Combined with weight loss, physical activity and a healthy diet, quitting can help some people with type 2 diabetes reach normal blood sugar levels. Read more on whether diabetes can be reversed.

How does smoking damage body cells?

Smoking makes the body less sensitive to insulin and alters how proteins that help regulate glucose are expressed, amplifying the risk of type 2 diabetes. The chemicals in tobacco smoke also cause inflammation and damage to blood vessel linings, which contribute to the heart and circulation complications that affect people with diabetes.

Is secondhand smoke linked to type 2 diabetes?

Secondhand smoke has been associated with an elevated chance of developing type 2 diabetes, indicating a probable relationship between the two. More research is needed to understand the association fully, but avoiding smoke exposure is a sensible precaution for anyone with or at risk of diabetes.

Is smoking bad for diabetes even if my blood sugar is well controlled?

Yes. Even with good blood sugar control, smoking independently damages blood vessels, raises blood pressure and increases the risk of heart attack, stroke, kidney disease and poor circulation in the legs and feet. For people with diabetes these risks are already elevated, so smoking adds to them rather than replacing them.

References, studies and sources

• Centers for Disease Control and Prevention (CDC). Smoking and Diabetes. https://www.cdc.gov/tobacco/campaign/tips/diseases/diabetes.html
• Pan, A., Wang, Y., Talaei, M., Hu, F. B., Wu, T. (2015). Relation of active, passive, and quitting smoking with incident type 2 diabetes: a systematic review and meta-analysis. The Lancet Diabetes & Endocrinology. https://doi.org/10.1016/s2213-8587(15)00316-2
• Chiolero, A., Faeh, D., Paccaud, F., Cornuz, J. (2008). Consequences of Smoking for Body Weight, Body Fat Distribution, and Insulin Resistance. The American Journal of Clinical Nutrition, 87(4), 801–809. https://doi.org/10.1093/ajcn/87.4.801
• American Diabetes Association. Diabetes overview and risk factors. https://diabetes.org/
• National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). Diabetes. https://www.niddk.nih.gov/health-information/diabetes

About the author: Dr. Matthew Capozzi, DPM, FACFAS, CWS, is a board-certified foot surgeon through the American Board of Foot and Ankle Surgery. He is a Diplomate of the American Academy of Wound Management and Fellow of the American College of Foot and Ankle Surgeons. He completed a three-year residency program in Foot and Ankle Reconstructive Surgery at St. Francis Hospital & Medical Center in Hartford, CT in 2010. Dr. Capozzi is a board-certified Wound Specialist® granted by the American Academy of Wound Management.

Healthcare disclaimer: Always consult your physician before beginning any program. This general information is not intended to diagnose any medical condition or to replace your healthcare professional. If you experience any pain or difficulty, stop and consult your healthcare provider. CircuFiber socks are a general wellness product intended to promote a temporary increase in local blood flow and circulation; they are not intended to diagnose, treat, cure, or prevent any disease. Individual results vary.