Tobacco use in diabetes mellitus: a retrospective cohort study to determine the effect of snuff tobacco use on diabetes mellitus complications over a period of nine years



diabetes mellitus, diabetic retinopathy, diabetic nephropathy, tobacco, smoking, snuff, smokeless tobacco


Background: Diabetes mellitus (DM) affects millions of people worldwide, with associated morbidity and premature mortality exacerbated by all forms of smoking. The effects of smokeless tobacco, such as snuff and chewing tobacco, have not been well researched. The use of these products is on the increase and is an important public health issue.

Objectives: The objective is to assess the difference between snuff tobacco use and non-tobacco use with regard to all-cause mortality, diabetic nephropathy (DN), and diabetic retinopathy (DR) over a nine-year period.

Methods: The records of 1 241 patients were assessed at the diabetic clinic at Kalafong Provincial Tertiary Hospital. Patient data extracted from the database included demographic information, clinical observations, and laboratory data. All data regarding changes in tobacco use were extracted. Survival analyses were done using Kaplan–Meier analysis with log-rank tests to assess the relationship between snuff use and time to the development of diabetes complications and mortality. To adjust for confounders such as diabetic control and duration, as well as systolic hypertension, Cox proportional hazards modelling was done with the same outcome measures.

Results: Of the 1 241, 120 patients died, representing a natural all-cause mortality of 9.7%. There was no statistically significant difference between snuff users and non-snuff users with regard to all-cause mortality after adjustment for age, smoking, and diastolic blood pressure. The HR for snuff use was 1.116 (CI = 0.603–2.064) (p = 0.726) after adjustment for age (HR 1.042, CI 1.026-1.058, p < 0.001), smoking (HR 1.66, CI = 1.126–2.447, p = 0.01), and diastolic blood pressure (HR 1.014, CI 1.004–1.025, p = 0.007).

Conclusion: This study could not demonstrate any additional risk to all-cause mortality, diabetic nephropathy, or diabetic retinopathy due to the use of snuff in diabetic patients.

Author Biographies

RA Ally, University of Pretoria

Department of Internal Medicine, School of Medicine, Faculty of Health Sciences, University of Pretoria, South Africa

D van Dyk, University of Pretoria

Department of Internal Medicine, School of Medicine, Faculty of Health Sciences, University of Pretoria and Diabetes Research Centre, University of Pretoria and Kalafong Provincial Tertiary Hospital, South Africa






Original Research