Smoking can increase the risk of type 1 diabetes
Adult smoking appears to increase the risk of adult-onset type 1 diabetes, with stronger effects in those with a family history of diabetes, highlighting the importance of investigating modifiable risk factors for adult-onset type 1 diabetes.
A recently published study by researchers at the Institute of Environmental Health, Karolinska Institutet, shows that exposure to maternal smoking during pregnancy may reduce the risk of developing type 1 diabetes in childhood, but not in adulthood. In contrast, there was evidence that adult smoking may increase the risk of adult-onset type 1 diabetes.
The study used data from Swedish nationwide registers and prospectively analysed the incidence of type 1 diabetes in relation to maternal smoking during pregnancy and adult smoking. For the analysis of maternal smoking, the study included a total of 3,170,386 individuals, of whom there were 18,745 cases of type 1 diabetes. In the case of adult smoking, 1,608,291 people were included, with 1,274 cases of type 1 diabetes.
The results showed that prenatal exposure to smoking was associated with a lower incidence of type 1 diabetes in childhood and young adulthood, especially in the 20-24 age group. The hazard ratio (HR) for this age group was 0.76. However, this protective effect was not observed in older people. However, the HR associated with adult smoking was estimated to be 1.14 overall, suggesting an increased risk. Notably, this risk was even more obvious in those with a family history of diabetes, where the HR was 1.34.
The authors discuss that these findings are consistent with observations in persons with LADA (latent autoimmune diabetes in adults) where smoking was associated with a 30% higher risk. Further, they speculate that the proposed mechanisms include the adverse effects of smoking on insulin sensitivity, which may accelerate the autoimmune process in type 1 diabetes.
These findings provide insights into the origins of type 1 diabetes and highlight the importance of the foetal developmental period. In addition, the study emphasizes the importance of studying adult-onset type 1 diabetes, as it is more common in adults than previously thought, with an estimated median age of diagnosis of 29 years.
First author of the recently published article is Yuxia Wei from the ESTRID group.
Prenatal and adult exposure to smoking and incidence of type 1 diabetes in children and adults-a nationwide cohort study with a family-based design.
Wei Y, Edstorp J, Feychting M, Andersson T, Carlsson S
Lancet Reg Health Eur 2024 Jan;36():100775