Smoking prevalence after bariatric surgery is the same as pre-surgery levels within seven
years of the procedure, according to research led by the University of Pittsburgh Graduate School of Public Health. This is despite one in seven adult patients smoking cigarettes the year prior to undergoing surgery and nearly all successfully quitting at least a month before their operation. The findings suggest that there may be missed opportunities to engage patients in interventions to improve long-term smoking cessation rates, particularly at regular post-surgery check-ups.
"Smoking cessation prior to surgery is strongly recommended to reduce surgical complications," said lead author, Dr Wendy King, associate professor of epidemiology at Pitt Public Health. "But there isn't the same emphasis on maintaining cessation after surgery. Our findings show that there is a need for ongoing support in order to reduce and quickly respond to relapses."
Reporting their findings in the study, ‘Changes in Smoking Behavior Before and After Gastric Bypass, published in the Annals of Surgery, King and her colleagues followed 1,770 adults who underwent Roux-en-Y gastric bypass (RYGB) surgery for seven years post-surgery, annually surveying them about their smoking habits. The participants were enrolled in the National Institutes of Health-funded Longitudinal Assessment of Bariatric Surgery-2 (LABS-2), a prospective, observational study of patients undergoing weight-loss surgery at one of ten hospitals across the US.
More than 45% of the participants reported a history of smoking prior to surgery, with 14% still smoking in the year before surgery, which fell to 2% in the month before surgery. The rate rebounded to nearly 10% in the year following surgery and steadily climbed back to 14% by seven years post-surgery.
"Interestingly, the people who picked up smoking post-surgery weren't just the people who quit smoking in the year prior to surgery, presumably to prepare for the operation,” said co-author, Dr Gretchen White, assistant professor in Pitt's School of Medicine. “Many had never smoked to begin with."
Additionally, people who identified as smokers post-surgery smoked more, going from an average of a dozen cigarettes per day in the year before surgery to more than 15 cigarettes per day seven years post-surgery. These findings contrast with concurrent reductions in smoking prevalence and intensity in the general US population.
The researchers hypothesised that weight control would be a key reason weight-loss patients took up smoking after surgery, but found that the prevalence of smoking for weight control was actually fairly stable over time, at about 2% pre- and post-surgery, and did not appear to be related to smoking more cigarettes. King noted that "this surprised everyone, as there is a general assumption that weight control is a main motivator for smoking."
While the study was not designed to find a biological reason for the results, the researchers did observe that gastric bypass patients were more likely to smoke post-surgery than patients who underwent gastric banding. A recent study showed that gastric bypass increases exposure to the psychoactive nicotine metabolite cotinine. Just as gastric bypass increases the risk of alcohol use disorder due to changes in alcohol metabolism that lead to higher and quicker elevation of blood alcohol levels, it may also increase risk of smoking via nicotine metabolism, King suggested.
The scientists identified several factors that predict which patients would be most likely to take up smoking after surgery. Not surprisingly, a prior history of smoking was the greatest risk factor. In addition, younger age, poverty, being married or living as married, and drug use were each associated with increased risk.