Study confirms link between smoking tobacco and diabetes, clears nicotine

The results of a Swedish study confirm the link between diabetes and smoking, with the incidence being noticeable up to 15 years after quitting smoking. Consumption of nicotine in the form of snus, on the other hand, would be ruled out as a cause of type 2 diabetes.

Several lifestyle risk factors have been identified in the development of type 2 diabetes. Among these factors, smoking – active or passive – has already been identified as one of the causes of this diabetes. However, Swedish and American researchers wanted to validate whether this risk factor was also true in ex-smokers and snus users.[1].

Smoking has a clear impact on the development of type 2 diabetes

The study is based on a cohort study of 36,742 people who completed a self-administered questionnaire on their lifestyle habits (weight, height, household composition, physical activity, smoking, snus use, alcohol and coffee consumption) and their level of education.[2]. These data were cross-referenced with those from the Swedish National Patient Register based on the personal identification number, which is unique to each Swede. Participants were aged 56 to 95 years, with a mean age of 69.8 years. Type 1 diabetes was excluded from the study.

The results show that in this sample, 9 % were active smokers, 38 % were ex-smokers and 5.5 % were snus users. 2,264 people were identified as having been diagnosed with type 2 diabetes or receiving anti-diabetic treatment for this type of diabetes, with an incidence rate of 8 per 1000 person-years. An increased risk of type 2 diabetes was found in smokers and ex-smokers, compared with people who had never smoked. This risk of type 2 diabetes decreased after smoking cessation, but remained significantly increased during the fifteen years following smoking cessation. Current or former snus use, however, offered little difference with the reference group of non-smokers, once the results were adjusted for other potential risk factors.

Persistence of incidence of diabetes in ex-smokers

From this study, the authors conclude that the impact of smoking on the onset of type 2 diabetes is confirmed in smokers and that it persists up to 15 years after quitting smoking. These authors also suggest that the absence of a significant impact of snus use on type 2 diabetes would seem to implicate smoked tobacco more than nicotine in the onset of this pathology. They admit, however, that the small number of snus users does not allow a ruling on this hypothesis, other studies having on the contrary shown an impact of snus use on type 2 diabetes.

The links between smoking and diabetes are already widely documented, with the risk of developing type 2 diabetes estimated to be 30 to 40 times higher than that of smoking.[3]. They find further confirmation here, which underlines that the damage from smoking can also be observed many years after stopping smoking.

Keywords: type 2 diabetes, smoking, ex-smokers, snus

M.F.

[1] Tobacco pouches that are placed between the gum and lip. Often confused with nicotine pouches, which do not contain tobacco.

[2] Titova O, Baron J, Fall T, Michaëlsson K, Larsson S, Swedish Snuff (Snus), Cigarette Smoking, and Risk of Type 2 Diabetes, Am J Prev Med 2023;000(000):1−7 (in press – February 20, 2023). https://doi.org/10.1016/j.amepre.2023.01.016

[3] Durlach V, Vergès B, Al-Salameh A, Bahougne T, Benzerouk B, Berlin I, Clair C, Mansourati J, Rouland A, Thomas D, Thuillier P, Tramunt B, Le Faou AL, Smoking and diabetes interplay: A comprehensive review and joint statement, Diabetes & Metabolism, 2022, Volume 48, Issue 6, 101370.