To examine the association between cigarette smoking and the incidence and progression of diabetic retinopathy.
A population-based cohort study of 708 adult younger-onset persons with diabetes, 485 older-onset persons taking insulin, and 502 older-onset persons with diabetes not taking insulin who participated in baseline, 4-year, and 10-year examinations. Incidence and progression of retinopathy and progression to proliferative retinopathy were measured as determined by fundus photography.
Neither smoking status nor pack-years smoked showed significant associations with increased risk of retinopathy.
Cigarette smoking is not a risk factor for the long-term incidence of retinopathy. However, the failure to find an association between smoking and diabetic retinopathy does not imply that persons with diabetes who smoke should not stop as cigarette smoking is a risk factor for other complications and associated conditions of diabetes, particularly cardiovascular disease.