Smoking Cessation and the Risk of Diabetes Mellitus and Impaired Fasting Glucose: Three-Year Outcomes after a Quit Attempt

<div><p></p><p>Weight gain after smoking cessation may increase diabetes mellitus and impaired fasting glucose (IFG) risk. This study evaluated associations between smoking cessation and continued smoking with incident diabetes and IFG three years after a quit attempt. The 1504 smokers (58% female) were mean (standard deviation) 44.7 (11.1) years old and smoked 21.4 (8.9) cigarettes/day. Of 914 participants with year 3 data, the 238 abstainers had greater weight gain, increase in waist circumference, and increase in fasting glucose levels than the 676 continuing smokers (p≤0.008). In univariate analyses, Year 3 abstinence was associated with incident diabetes (OR = 2.60, 95% CI 1.44–4.67, p = .002; 4.3% absolute excess) and IFG (OR = 2.43, 95% CI 1.74–3.41, p<0.0001; 15.6% absolute excess). In multivariate analyses, incident diabetes was associated independently with older age (p = 0.0002), higher baseline body weight (p = 0.021), weight gain (p = 0.023), baseline smoking rate (p = 0.008), baseline IFG (p<0.0001), and baseline hemoglobin A1C (all p<0.0001). Smoking more at baseline predicted incident diabetes among eventual abstainers (p<0.0001); weighing more at baseline predicted incident diabetes among continuing smokers (p = 0.0004). Quitting smoking is associated with increased diabetes and IFG risk. Independent risk factors include older age, baseline body weight, baseline glycemic status, and heavier pre-quit smoking. These findings may help target smokers for interventions to prevent dysglycemia.</p><p>Trial Registration</p><p>Clinicaltrials.gov <a href="http://www.clinicaltrials.gov/ct2/show/NCT00332644." target="_blank">NCT00332644</a></p></div

Baseline Participant Characteristics by Year 3 Smoking and Missingness Status.

<p><i>All values are mean (standard deviation); *with post-hoc tests of significant group differences.</i></p

Univariate Predictors of Year 3 Glycemic Group Status.

<p><i>IFG  =  impaired fasting glucose; DM  =  diabetes mellitus.</i></p><p><i>Asterisks indicate significance levels for the variables in the prediction of either Year 3 IFG or diabetes mellitus by univariate multinomial logistic regressions; the group consisting of participants with normal glycemic status was the reference condition for the IFG and DM groups:</i><b>*  = p<0.05; **  = p<0.01; ***  = p<0.0001.</b></p

Mixed-Effects Models Testing Selected Repeated Measures as a Function of Time and Year 3 Smoking Status.

<p><i>All values are mean (standard deviation); note: 89 participants with diabetes mellitus at baseline are omitted from these analyses.</i></p

Best-Fitting Multivariate Multinomial Logistic Regression Model Predicting Year 3 Glucose Group (Normal, Impaired Fasting Glucose, Diabetes Mellitus).

<p><i>Reference group  =  normal Year 3 glycemic status.</i></p><p><i>IFG  =  impaired fasting glucose.</i></p

Year 3 Weight Change, Diabetes Mellitus, and Impaired Fasting Glucose Status.

<p><i>Values are mean (standard deviation); diabetes mellitus  =  diabetes mellitus; IFG  =  impaired fasting glucose. “No diabetes” includes Year 3 participants who met criteria for IFG.</i></p><p><i>Year 3 participants who met criteria for diabetes mellitus are excluded from the IFG analyses.</i></p