Inflammation markers predict increased weight gain in smoking quitters

Objective: Undesirable weight gain often follows smoking cessation. We investigated whether weight gain after smoking cessation is greater in those with higher levels of inflammatory markers. Research Methods and Procedures: We studied weight gain and risk of a large gain (greater than or equal to 90th percentile) over 3 years in a cohort study of 11,687 U.S. men and women, 45 to 64 years old, with focus on the 2664 who continued and the 493 who quit smoking. Results: Among new quitters, adjusted weight gain for those in the highest (vs. lowest) quartile of leukocytes was 0.56 kg/yr more (95% confidence interval, 0.17 to 0.95); for those in the highest (vs. lowest) quartile of fibrinogen, 0.60 kg/yr more (95% confidence interval, 0.27 to 0.92; p = 0.02 and 0.001 for adjusted smoking status by leukocyte and smoking status by fibrinogen interaction terms, respectively). In adjusted analyses, the odds ratio for a large gain associated with quitting (vs. continuing) was 6.2 for those in the highest quartile of leukocytes vs. 2.2 for those in the lowest leukocyte quartile (p = 0.03 for smoking status by inflammatory marker interaction). Similarly, the odds ratio for a large gain associated with quitting was 4.5 in the highest fibrinogen quartile vs. 2.5 in the lowest (p = 0.09 for the interaction term). Discussion: Weight gain after smoking cessation is increased in those with higher baseline levels of leukocytes and fibrinogen. These findings suggest a close relationship between inflammatory mediators and regulators of energy balance that may have important clinical implications.