Feasibility of Using Biomarkers to Examine Associations between Commercial Cigarette Smoking and Glycemic Levels during a Smoking Cessation Attempt

Introduction: American Indians have a higher prevalence of type 2 diabetes mellitus (T2DM) and commercial cigarette smoking compared to other racial groups. The complex relationship between smoking, cessation, and glycemic control is not well understood. We examined the feasibility of using continuous glucose monitoring (CGM) and mobile health (mHealth) to understand the acute effects of smoking and cessation on glycemic levels.

Methods: We recruited T2DM current smokers aged 21 to 75 in the Cherokee Nation Health System willing to make a cessation attempt. Patients wore 14-day FreeStyle Libre Professional CGM sensors to examine glycemic levels two weeks pre-quit and two weeks post-quit. Participants completed daily smartphone assessments using mHealth to report cigarettes, meals, exercise, tobacco, and nicotine replacement therapy. Remote carbon monoxide (CO) sensors were used to biochemically verify abstinence. Participants completed a semi-structured interview at exit to describe their experiences using the technology.

Results: We enrolled 13 participants and 10 made a smoking cessation attempt defined as at least a 10% reduction in cigarette consumption. Most participants who reduced cigarette consumption experienced a decrease in mean glucose. Many experienced episodes of hypoglycemia post-quit. Participants on average experienced a 13% absolute change in desired time in range in the two weeks post-quit but the direction varied by baseline HbA1c. For those who normally experienced high glucose levels, their glucose levels also decreased and for some led to an increase in time in range. Glycemic variability increased in most patients, and most recorded weight loss. Participants reported satisfaction with the technology.

Conclusion: A decrease in cigarettes per day resulted in a decrease in glucose levels initially, which suggests an acute change in glucose metabolism. A more granular view of acute glycemic changes using CGM during smoking cessation could inform tailored interventions for smokers with T2DM.