Smoking significantly increases the risk of diabetes and worsens the condition in patients with diabetes. Its main effects include raising blood glucose, increasing insulin resistance, damaging blood vessels, exacerbating complications, and reducing treatment efficacy.
I. Raising Blood Glucose
Smoking directly increases blood glucose levels.Harmful substances such as nicotine in tobacco stimulate the release of glucose-raising hormones (epinephrine, cortisol), which promote glucose release from the liver and inhibit insulin secretion and action, leading to higher blood glucose.For diabetic patients, this makes glycemic control much more difficult.
II. Increasing Insulin Resistance
Smoking is an important risk factor for insulin resistance.Long-term smoking impairs cell function, interferes with insulin signal transduction, and increases insulin resistance — a core mechanism in the development and progression of type 2 diabetes.
III. Damaging Blood Vessels
Smoking is directly toxic to vascular endothelial cells and accelerates atherosclerosis.In diabetic patients, who already have more vulnerable blood vessels, smoking further damages macro‑ and microvessels, increasing the risk of myocardial infarction and stroke.
IV. Worsening Complications
Smoking significantly accelerates diabetic complications:
Diabetic nephropathy: accelerates the decline in glomerular filtration rate
Diabetic retinopathy: worsens retinal ischemia and neovascularization
Diabetic neuropathy: increases nerve ischemia and injury
Diabetic foot: severely impairs lower‑extremity circulation, raising the risk of gangrene and amputationV. Reducing Treatment Efficacy
Smoking alters the metabolism of some glucose-lowering drugs, reducing their effectiveness.Smokers often have other unhealthy habits (irregular diet, physical inactivity), which further weaken overall treatment outcomes.
For patients with diabetes, quitting smoking is one of the most important non-pharmacological interventions to control the disease and delay complications.It is strongly recommended to make a smoking cessation plan and seek professional support from smoking cessation clinics.