While smoking is damaging to everyone’s health, the nicotine in cigarettes is thought to be even more dangerous for people suffering from diabetes. In lab experiments, researchers have discovered that nicotine raised blood sugar levels; and the more nicotine that was present, the higher the blood sugar levels were. Higher blood sugar levels are linked to an increased risk of complications from diabetes, such as eye and kidney diseases.
“Smoking is really harmful for diabetics. It’s even more harmful to them than to a non-diabetic,” said study author Xiao-Chuan Liu, an associate professor in the department of chemistry at California State Polytechnic University in Pomona. “This study should encourage diabetics to quit smoking completely, and to realize that it’s the nicotine that’s raising blood sugar levels.” For the same reason, it is important to limit the use of nicotine replacement products, such as nicotine patches, if they are to be used for the long-term, Liu said. “Don’t use electronic cigarettes or nicotine gum for a long time. You need to stop nicotine intake,” he advised.
It was already well-established before that smoking increased the risk of complications in people with diabetes. What hasn’t been clear, however, is whether or not there is a specific component of cigarettes that increases this risk.
In order to test whether or not nicotine contributed to higher blood sugar levels, Liu and his colleagues added equal amounts of glucose to samples of human red blood cells. They then added varying levels of nicotine to each sample of red blood cells for either one or two days. The hemoglobin A1C (HbA1C) levels of the samples where then tested, which is a measure of the percentage of red blood cells which have glucose molecules attached to them. In the management of diabetes, the HbA1C test gives doctors an idea of average blood sugar levels for the past three months or so. Most diabetics aim for a level of 7% or less, based on American Diabetes Association guidelines. The researchers found that nicotine raised Hb1Ac; with the lowest dose of nicotine raising Hb1AC levels by 8.8%, and the highest dose raising it by 34.5%.
Dr. Joel Zonszein, director of the Clinical Diabetes Center at Montefiore Medical Center in New York City, said that while researchers showed that nicotine can significantly raise A1C levels in the lab, it is important to also know if it does so in the body. Whether or not nicotine is the specific reason that blood sugar levels are higher in smokers, he said, “Everybody — whether they have diabetes or not — should stop smoking. Patients with diabetes already have a much higher risk of cardiovascular disease, and smoking adds to that.” He also said that using nicotine replacement products for a month or two is fine. “If nicotine replacement is used for a short period of time with smoking cessation as the goal, there’s no risk. But it’s not OK if someone plans to replace smoking with nicotine replacement products indefinitely,” said Zonszein.