People with diabetes who smoke are more than twice as likely to have an episode of severe hypoglycemia, or very low blood sugar, as those who have never smoked.

Loss of sugar can cause mental confusion, or even coma or seizures in severe instances. Smoking, through its effect on hormone regulation and insulin clearance, has been hypothesized to result in severe hypoglycemia.

Quoting a study published in the journal Diabetes Care, Dr. Aggarwal said that after taking account of other factors, smoking conferred a 2.6-fold increased risk of having severe hypoglycemia.

Furthermore, smoking was associated with similarly increased odds of having diabetes-related nerve damage, impaired kidney function, and sight-threatening retinal defects.