Smoking is the leading preventable cause of death and disability. On average, people who smoke die 10 years earlier than non-smokers.¹ The statistics are always staggering, with millions of people affected.

But quitting smoking is hard. Extremely hard. People who quit will often say that it was one of the hardest things they have ever done in their life. One of the major barriers to smoking cessation is weight gain. Weight concerns may impact a patient's initial desire to quit as well as his or her long-term success. Weight gain is a legitimate issue, particularly because it can lead to insulin resistance and then borderline or even overt diabetes.

The conversation often goes like this:

Doctor: Quitting smoking is the most important thing you can do to improve your cardiovascular health.
Patient: I know. Everyone knows that. But I am really worried I will gain weight. My weight is already a problem for me, especially because my sugar has been a little high. My sister is heavy, and she just found out that she has diabetes.
Doctor: Some weight gain is common with quitting smoking. However, the dangers of continuing to smoke are far worse, even if you do gain a little bit of weight.

These statements would be accurate based on prior research, including a recent study looking at the cardiovascular impact of weight gain after smoking cessation in more than 108,000 Korean men.² In the Korean study, smoking cessation decreased the risk of myocardial infarction and stroke, regardless of the change in body mass index (BMI).

Prior theoretical calculations have also estimated that a patient would have to increase his or her BMI by nearly 16 kg/m² to offset the dangers of smoking.³ For example, a person who is 5'5" tall and weighs 130 pounds, he or she would have to gain approximately 96 pounds to offset the benefits of smoking cessation. However, these calculations are only theoretical.

Imaging the awful scenario in which the doctor has to say: "Indeed, weight gain is a problem. And in fact, if you do gain weight, then you may develop diabetes and your chances of dying may be just as high as if you had kept on smoking!"

The study recently published by Hu and colleagues addresses this exact question.⁴ The investigators prospectively looked at changes in smoking status and body weight in three cohorts (the Nurses' Health Study, the Nurses' Health Study II, and the Health Professionals Follow-up Study), which were pooled to increase statistical power. They found that the risk of diabetes did temporarily increase after quitting smoking, with a peak at 5 to 7 years. Not surprisingly, the hazard ratios for the risk of diabetes were higher with more weight gain. But they found that the risk of diabetes then decreased over time, dropping to the rate of nonsmokers for those with the longest follow-up duration (after 30 years).

The most critical study finding was that cardiovascular and overall mortality decreased substantially across the board after quitting, no matter how much weight was gained. The study definitively concludes that weight gain with smoking cessation does not mitigate the health benefits in terms of reducing both cardiovascular and all-cause mortality.

Thus, the conversation can still continue as follows:

Doctor: I can understand that you are concerned about gaining weight. But a recent large research study showed that even if you do gain weight after you quit smoking, you will still live longer and your risk of heart attack and stroke will be lower when you quit. This is the case even if you develop diabetes in the short-term.

Of note, the risk of diabetes was not increased among those who did not gain weight. Thus, the next logical question is how to prevent excessive weight gain for patients who are trying to quit smoking. Hu and colleagues and the accompanying editorial both addressed this issue, which is of enormous consequence given that 40% of American adults are either overweight or obese.⁵ This question may be even more important in the real world than in this study, which included mostly white (97.6%) health professionals whose mean baseline body-mass index was only 24.1 kg/m².

The study found that each increase in 10 MET-hours per week in physical activities was associated with 0.13 kg less weight gain. Walking briskly at 3 mph is approximately 3.3 METs per hour. Doing a 3.3 MET activity for 60 minutes equals 198 MET-minutes (or 3.3 MET-hours). Thus, to achieve an extra 10 MET-hours (600 MET-minutes) per week, one would need to walk briskly for about 3 extra hours per week.

In addition, each 10-point increase in the Alternative Healthy Eating Index (AHEI) score was associated with 0.26 kg less weight gain.⁴ In keeping with prior studies, the authors thus concluded that increasing physical activity and improving diet quality may help to prevent excessive weight gain.

What if the patient is already overweight? Attempting to quit smoking and to lose weight simultaneously is an insurmountable challenge. The mantra of "Maintain, don't gain" should be promoted during the smoking cessation process. The first priority should always be smoking cessation. Weight loss can be addressed afterwards.

Pharmacologic treatment for smoking cessation may help to prevent excessive weight gain, but the benefits are often temporary. A Cochrane review found that medications including bupropion, fluoxetine, nicotine replacement therapy, and varenicline all reduced weight gain while taking the medication but only exercise interventions have been found to help over the long-term.⁶

The next step in the conversation may be:

Patient: OK. You have convinced me that the benefits of quitting are more important than my weight. But what can I do to try to lose weight or to prevent myself from gaining even more weight?
Doctor: Quitting smoking is the first priority for your health. But don't forget that all adults need a minimum of 30 minutes per day of brisk exercise. Keeping up this daily exercise regimen is important, particularly while quitting smoking. Your daily exercise, along with watching what you eat, will help you maintain your weight and help you prevent weight gain. After you quit smoking, we can work together on the weight loss.

In summary, the study by Hu et al is consistent with prior studies which have shown that weight gain with smoking cessation does not attenuate the cardiovascular benefits.⁷ These results are great news for patients and great news for the medical community, underscoring the plain fact that no other health intervention offers such a large potential benefit as smoking cessation.

References

1. Doll R, Peto R, Boreham J, Sutherland I. Mortality in relation to smoking: 50 years' observations on male British doctors. BMJ 2004;328:1519.
2. Kim K, Park SM, Lee K. Weight gain after smoking cessation does not modify its protective effect on myocardial infarction and stroke: evidence from a cohort study of men. Eur Heart J 2018;39:1523-31.
3. Diverse Populations Collaboration. Smoking, body weight, and CHD mortality in diverse populations. Prev Med 2004;38:834-40.
4. Hu Y, Zong G, Liu G, et al. Smoking cessatino, weight change, type 2 diabetes, and mortality. N Engl J Med 2018;379:623-32.
5. Hales CM, Carrol MD, Fryar CD, Ogden CL. Prevalence of obesity among adults and youth: United States, 2015-2016. NCHS Data Brief, No 288. National Center for Health Statistics. 2017.
6. Farley AC, Hajek P, Lycett D, Aveyard P. Inteventions for preventing weight gain after smoking cessation. Cochrane Database Syst Rev 2012;1:CD006219.
7. Tonstad S. Weight gain does not attenuate cardiovasuclar benefits of smoking cessation. Evid Based Med 2014;19:25.

Clinical Topics: Cardiovascular Care Team, Diabetes and Cardiometabolic Disease, Prevention, Exercise, Smoking

Keywords: Diabetes Mellitus, Type 2, Weight Gain, Body Mass Index, Weight Loss, Smoking Cessation, Bupropion, Fluoxetine, Nicotine, Insulin Resistance, Smoking Cessation, Smoking, Research Personnel, Obesity, Body Weight, Overweight, Diabetes Mellitus, Stroke, Myocardial Infarction, Exercise Therapy, Epidemiologic Studies, Metabolic Syndrome

< Back to Listings