Risk for weight gain
Dr. Rouland tried to reassure patients about the risk for gaining weight. “Weight gain is not inevitable. There is a risk for this, but it’s temporary. And, even with some weight gain, the cardiovascular benefits are still indisputable.”
A study carried out in 2013 focused specifically on this point, with an average post-cessation weight gain of 3.8 kg (8.4 lb) seen in diabetic individuals in the first 4 years after stopping smoking and of 0.1 kg (0.2 lb) thereafter. A time-based effect was observed with regulation of excess weight post-cessation over time, as seen in the general population (3 kg [6.6 lb] on average in nondiabetic individuals).
Weight gain tends to occur mainly in the immediate post-cessation period, essentially in the first 3 months, and there is a large variation in weight change. Some people gain a lot (from 5 to 10 kg [11 to 22 lb], or even more than 10 kg); others lose weight (20% of diabetic former smokers in the first month, 7% after 12 months), and 25% gain less than 5 kg (11 lb).
Blood glucose imbalance
“A risk for blood glucose imbalance has been reported after smoking cessation, although this is very slight and only temporary,” said Dr. Rouland.
A British retrospective study examined this question, focusing on glycated hemoglobin in patients with type 2 diabetes. Hemoglobin A1c increased by 0.21% (95% CI, 0.17-0.25; P < .001) within the first year after quitting. A1c decreased as abstinence continued and became comparable to that of continual smokers after 3 years. This increase in A1c was not mediated by weight change.
Another study published in 2018 on the topic of type 2 diabetes also reported on the risk for poor glycemic control (defined as A1c > 7%) persisting for 10 years after smoking cessation (odds ratio, 1.23; 95% CI, 1.06-1.42). Thereafter, between 10 and 19 years post-cessation, the OR decreased to 0.97 (95% CI, 0.80-1.19, NS). Beyond 20 years post-cessation, the OR was 1.14 (95% CI, 0.89-1.44, NS) and was therefore no longer significant.
Regardless, “the risk for poor glycemic control is lower in quitters than in active smokers,” said Dr. Rouland.
Quitting and diabetes risk
Will a smoker’s increased risk for diabetes drop when he or she stops smoking? “This is essentially what happens,” Dr. Rouland confirmed, “and his or her increased risk for metabolic syndrome also drops. One meta-analysis revealed a time-based effect.
“Patients who had stopped smoking less than 5 years previously had an increased relative risk for type 2 diabetes, and this risk dropped to 1.11 after more than 10 years of not smoking. Moreover, this relative risk for type 2 diabetes remained lower than that of active smokers, at between 1.19 and 1.60, depending on tobacco use.”
In regard to the risk for metabolic syndrome, those who quit smoking seem to have an increased risk of 10%, compared with nonsmokers (RR = 1.10, 1.08-1.11; P < .001). “But yet again, this increased risk is much lower than that of active smokers, whose risk is between 37% (less than 20 cigarettes/day) and 71% (more than 20 cigarettes/day).”