Patients with type 2 diabetes who quit smoking are likely to see a temporary deterioration in their glycaemic control that can last up to three years, according to UK researchers.
Researchers from Coventry University examined primary care records for 10,692 adult smokers with type 2 diabetes over six years to investigate whether or not quitting was associated with altered diabetes control.
“People with diabetes should continue to make every effort to stop smoking”
Their study found that in the 3,131 people who quit and remained abstinent for at least one year, HbA1c increased by 2.3mmol/mol (0.21%) before decreasing gradually as abstinence continued.
In the same period, 5,831 continual smokers experienced a more gradual increase in HbA1c, to the extent that HbA1c levels in quitters became comparable with the levels seen in continual smokers three years after quitting.
The researchers also concluded that weight changes often associated with quitting smoking did not significantly alter the association between smoking cessation and HbA1c levels.
Previous research has shown that an 11mmol/mol reduction in the HbA1c level of a diabetes patient will result in them being 16% less likely to experience heart failure and 37% less likely to experience microvascular complications.
Lead study author Dr Deborah Lycett said: “Stopping smoking is crucial for preventing complications that lead to early death in those with diabetes.
“Knowing that deterioration in blood glucose control occurs around the time of stopping smoking helps to prepare those with diabetes and their clinicians to be proactive in tightening their glycaemic control during this time,” she said.
The study findings have been published online in The Lancet Diabetes & Endocrinology.