A temporary deterioration in glycemic control, lasting up to 3 years, is linked to smoking cessation in adults with type 2 diabetes, according to recent study findings published in The Lancet Diabetes & Endocrinology.

“Knowing that deterioration in blood glucose control occurs around the time of stopping smoking helps to prepare those with diabetes and their clinicians to be proactive in tightening their glycemic control during this time,” Deborah Lycett, PhD, of the faculty of health and life sciences at Coventry University in the United Kingdom, said in a press release.

Deborah Lycett

Lycett and colleagues evaluated data from 10,692 adult smokers with type 2 diabetes from The Health Improvement Network to determine whether diabetes control deteriorates temporarily after smoking cessation and whether weight change mediates the relationship. The study began on Jan. 1, 2005, and follow-up was conducted until transfer out of practice, death or end of follow-up on Dec. 31, 2010.

During follow-up, 55% of participants did not attempt to quit smoking (continual smokers), whereas 29% quit for 1 year or more (long-term quitters). During the first year of smoking cessation, researchers found an increase in HbA1c of 0.21%.

HbA1c levels rose at the time of quitting but gradually decreased as cessation continued in long-term quitters, whereas HbA1c rose gradually in continual smokers. By 3 years after cessation, HbA1c levels in quitters became comparable to those in continual smokers.

According to the researchers, weight changes did not mediate the increase in HbA1c levels.

“Stopping smoking is crucial for preventing complications that lead to early death in those with diabetes,” Lycett said. “So, people with diabetes should continue to make every effort to stop smoking, and at the same time they should expect to take extra care to keep their blood glucose well controlled and maximize the benefits of smoking cessation.”