The nicotine in cigarettes is extremely addictive. That's why so many people find it very hard to quit smoking, even if they desparately want to. Research has shown that diabetics who smoke have higher blood sugar levels than diabetics who do not smoke. If you have not been diagnosed with type 2 diabetes, and you're a smoker, this is another good reason to try to quit: smokers are at higher risk for developing diabetes. Quitting can help to reduce that risk, even if you can't change some of the other risks for the disease (age, ethnicity, family genetics, etc).
Diabetics who smoke put themselves at higher risk not just for the risks due to smoking, but also higher risk for an accelerated onset and/or increased severity of diabetes-related complications. For example, smoking can cause atherosclerosis (hardening of the arteries), which hinders the flow of blood and oxygen to the major organs of our bodies. People with diabetes are already at higher risk for heart attack and stroke; add smoking to the mix and the risk increases significantly again.
Smoking also increases the amount of glucose in the blood; it increases the risk of kidney damage and nerve damage; it increases the level of LDL (the 'bad' cholesterol) and decreases the amount of HDL (the 'good' cholesterol) in the blood; and it increases the amount of triglycerides (fats) in the blood. In short, it makes diabetes treatment more difficult.
Quitting smoking is undoubtedly very difficult for many people. Nicotine is well-known to be an addictive substance. There are many methods that help with the process of quitting smoking, but no single method that works for everyone. Start by talking to a doctor and ask for recommendations. Even decreasing the amount smoked is a step in the right direction. For instance, if you know that you always want a cigarette after dinner, then use that time instead to go for a walk - you'll avoid the cigarette, plus as a bonus, the walk will be great for your blood sugar. Or put your cigarettes and lighter somewhere inconvenient and out-of-sight. Find something else you love to do (go for a bike ride, read a book, watch a favourite show, take a soothing bath) and do that instead for 30 minutes when a cigarette craving hits. Every little step helps.
Many people find support groups very helpful too, whether they are groups that meet in person or they are online groups or forums. Telling friends and family can help too. Keep a positive attitude and remember that quitting is a process - there may be a lapse, but keep trying. Every bit of progress is one step closer.
Diabetes and smoking are a toxic mix. With the knowledge of how smoking affects diabetes, only you can decide if and when you want to quit. It is never too late to quit smoking - the body has amazing healing powers, and removing nicotine and other toxins from our bodies can only improve our health.