Smoking and Diabetes: In a recent study featured in The Lancet Regional Health-Europe, researchers delved into the intriguing question of whether smoking during pregnancy or adulthood impacts the likelihood of developing type 1 diabetes (T1D) later in life.
The study explored T1D prevalence among individuals in Sweden, with a focus on maternal smoking during pregnancy and adult smoking habits. Leveraging data from various registers, including the Swedish National Population, Patient, Prescription, Diabetes, and more, researchers compared T1D patients to their non-diabetic siblings, employing cohort and sibling designs.
Using rigorous statistical models, the study unveiled intriguing patterns. Smoking during pregnancy appeared associated with a reduced risk of T1D during youth and young adulthood (20 to 24 years old) but showed no impact at older ages. Interestingly, adult smoking displayed an overall hazard ratio of 1.1, rising to 1.3 among those with a family history of diabetes. T1D patients exhibited a higher likelihood of having diabetic parents, lower education levels, obesity, and a smoking habit at baseline.
Sibling studies echoed the findings for maternal smoking and childhood T1D, but the protective effect didn’t extend into adulthood. Cohort analyses by age revealed a 24% to 30% reduced T1D incidence among children of smoking mothers compared to non-smoking mothers until 24 years of age, with no discernible difference between ages 25 and 30. Similarly, sibling studies showed a lower risk until ages 10 and 14, a trend towards lower risk between 15 and 19, but no reduction in risk at older ages.
Prenatal smoking correlated with a lower incidence of juvenile T1D, irrespective of a family history of diabetes. T1D risks among smokers varied marginally across cohorts, with no clear dose-response relationships. Intriguingly, combining data on adulthood and prenatal smoking exposure revealed a lower T1D incidence during adulthood only in individuals exposed to maternal smoking but without personal smoking habits. Notably, the Military Cohort results indicated no increase in T1D incidence among smokers and snus users.
In summary, the study’s findings suggest that maternal smoking during pregnancy may reduce the risk of T1D development in childhood, but this protective association diminishes in adulthood. Surprisingly, smoking during adulthood didn’t demonstrate a protective effect against T1D, and in some instances, results even hinted at contradictory outcomes. Furthermore, prenatal smoking didn’t show a significant association with adult-onset T1D risk. The study adds nuance to our understanding of the complex interplay between smoking habits and diabetes risk across different life stages.