Previous research has suggested that diabetes control deteriorates for one year following smoking cessation. A study of smoking cessation in diabetic patients was conducted to further investigate the association between quitting smoking and changes in diabetes control. The study reported an increase in HbA1c during the first year following quitting, which lasted up to 3 years. The observed changes were not associated with weight change in the participants. The authors suggest that patients with type 2 diabetes who quit smoking are more likely to experience reduction in glycemic control, which has the potential to increase microvascular complications.
Lycett, D, Nichols, L, Ryan, R, Farley, A, Roalfe, Al Mohammed, MA, Szatkowski, L, Coleman, T, Farmer, A, Aveyard, P “The association between smoking cessation and glycaemic control in patients with type 2 diabetes: a THIN database cohort study” The Lancet Diabetes & Endocrinology Volume 3, No. 6, p423–430, June 2015.