Cigarette Smoking and Progression of Retinopathy and Nephropathy in Type 1 Diabetes

Abstract

The objective of the present study was to analyse the association between cigarette smoking and progression of retinopathy and nephropathy, respectively, in a prospective multicentre study including 636 people with Type 1 diabetes: 81 % of the original cohort of consecutively referred patients, aged 15 to 40 years and free of severe late diabetic complications. At baseline, all patients had participated in a 5‐day in‐patient group treatment and teaching programme for intensification of insulin therapy. Patients were examined at recruitment, and after 1, 2, 3 and 6 years including assessment of smoking status, blood pressure, metabolic control, and degree of nephropathy. Degree of retinopathy was assessed by ophthalmoscopy or fundus photography at baseline and after 6 years. Several logistic regression analyses were performed by describing the responses retinopathy and nephropathy, respectively, either as progression yes/no or as actual status at the 6‐year follow‐up and by using different measures for smoking. Adjustments for important covariables were made. While significant associations between smoking, and retinopathy and nephropathy respectively, were found, the relations were variable depending on the statistical model used. The results show that the real associations between smoking and retinopathy and nephropathy are complex and that more emphasis should be put on the complete description of the response variables and the statistical models used in clinical and epidemiological research.

Low cumulative incidence of proliferative retinopathy in childhood-onset type 1 diabetes: a 24-year follow-up study

“…The effect of tobacco smoking on DR has long been contested [41][42][43]. In our study we did not find smoking to be a predictor for development of DR or PDR.…”

Estrogens and the diabetic kidney

“…In a randomized trial of captopril in type 1 DM, no effects of sex on the course of diabetic renal disease was observed after a 3-year follow-up. 11,18 Similarly, no effects of sex on the progression of diabetic renal disease over 2 years were observed in a prospective study examining the effects of smoking 19 or in a Danish cohort of normoalbuminuric patients followed for 11 years. 12 Male sex was found to be associated with a decline in glomerular filtration rate over 5 years in a prospective study of a smaller cohort of patients with established diabetic nephropathy.…”

Longitudinal study examining the risk factors for proliferative retinopathy and maculopathy in type-I diabetes: The Royal College of Physicians of Edinburgh Diabetes Register Group

“…The evidence for smoking in type-I diabetes is not clear cut. Smoking has been of borderline significance, 12 relevant only in the short term 14 or only significant depending on the statistical model used 13 in various previous studies. Our study again suggests a weak association between smoking and both proliferative disease and maculopathy in type-I diabetes, which is present on univariate analysis but not after adjustment for confounding factors.…”

“…Observational data have also identified the duration of diabetes, 6 raised cholesterol, [7][8][9] raised triglycerides, 9,10 and proteinuria 11 as risk factors. Smoking has previously been of borderline significance in type-I diabetes, 12,13 but may be of significance for patients who have had diabetes for less than 5 years. 14 Many of these studies have examined the risk factors for developing any sight-threatening retinopathy, but few studies have focused on the relative risks of developing proliferative retinopathy compared to maculopathy.…”