Key Point

Smoking cessation is beneficial for lung function; however, maximum benefit requires the control of weight gain, especially in men.

NEW YORK CITY—Controlling weight gain in individuals who have quit smoking could maximize improvement of lung function, particularly in men, according to Susan Chinn, DSc, and colleagues.¹

As part of the European Community Respiratory Health Survey, investigators measured the lung function of 6,654 people in 1991-1993, when participants were ages 20 to 44, and again in 1998-2002. Changes in lung function, smoking status, and weight were analyzed.

The average smoking intensity between surveys of participants who continued to smoke was just under one pack a day for men, less for women, and less still for those who had quit or quit and restarted smoking. Among men, FEV₁ declined by 5.7 mL/year per pack of cigarettes smoked each day between surveys; among women, FEV₁ declined by 5.8 mL/year per pack of cigarettes smoked each day.

The investigators also found that compared with individuals who had never smoked, decline in FEV₁ was lesser in male sustained quitters (mean difference, 5.4 mL/year) and in those who had quit smoking between surveys (mean difference, 2.5 mL/year) and greater in smokers (mean difference, -4.8 mL/year). Overall decline in FEV₁ was 32 mL/year among men and 25 mL/year among women, or 0.8% in both men and women.

WEIGHT GAIN AFTER SMOKING CESSATION

According to the investigators, mean weight and body mass index (BMI) increased in men and women during follow-up. The increase was greatest in those who had quit smoking and lowest in those who had restarted smoking, and applied to participants of all weight ranges. On average, men gained more weight than women; however, the increase in BMI was slightly greater in women.

The investigators said that when mean change in lung function was adjusted for change in either weight or BMI, a large effect on the difference in lung function between quitters and smokers was observed. “The relation of decline in lung function to increasing weight or BMI was substantially greater in men than in women for both change in FEV₁ and change in FVC,” the investigators explained. FEV₁ decreased by 11.5 mL/kg of weight gained in men and by 3.7 mL/kg of weight gained in women. This change in FEV₁ diminished the benefit of quitting smoking by 38% in men and by 17% in women, said the investigators.

“Our results strongly support the inclusion of a weight reduction intervention as part of randomized controlled trials of smoking cessation,” the investigators noted.

In an accompanying editorial, Graham A. Colditz, MD, DrPH, and Cynthia Stein, MD, MPH, recommended that “while ongoing research explores alternative pharmacological strategies to counter weight gain, emphasis should be placed on counseling patients to increase physical activity.”² They pointed out that beyond the short-term benefits, physical activity can also reduce the risk of mortality, coronary heart disease, and cancer.

Drs. Colditz and Stein emphasized that although lifestyle interventions have proven effective for controlling weight gain, individual efforts must be reinforced by the support of family members, counseling of health care providers, participation in community walking groups and exercise programs at work, and changes in regulations to provide access to safe areas for exercise.

—Karen L. Spittler

References
1. Chinn S, Jarvis D, Melotti R, et al. Smoking cessation, lung function, and weight gain: a follow-up study. Lancet. 2005;365:1629-1635.
2. Colditz GA, Stein C. Smoking cessation, weight gain, and lung function. Lancet. 2005;365:1600-1601.

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