Disease course and symptoms in smoking versus non-smoking patients with Celiac disease

Background and study aims: Knowledge about the impact of smoking in Celiac disease is limited. We aimed to assess clinical differences between smoking and non-smoking patients with celiac disease. Patients and methods: We conducted a cross-sectional questionnaire-based study among patients with Celiac disease distributed through a common interest group. Patients answered questions regarding the clinical manifestation of disease, adherence to a gluten-free diet and symptom development over time. Patients were asked whether they smoked at the time of diagnosis. Comparisons to the Swiss General Population were performed using data from the Swiss federal statistic office with data from the health survey 2012. Results: Data on smoking status was available from 1537 individuals. We found a significantly lower proportion of smokers among questionnaire respondents compared to the Swiss general population in the same time frame (8.5% vs 28.2%, p < 0.01). Compared to non-smokers, smokers had a higher age at diagnosis (39 years vs 32 years, p < 0.01) and more frequently reported diarrhea as an initial symptom (67% vs 56%, p =0.013). Smokers tended to adhere less strictly to a gluten-free diet than non-smokers (69% strict adherence vs. 77% p =0.052). Six and twelve months after diagnosis, the proportion of patients with symptomatic improvement was not different between smokers and non-smokers. Conclusions: We found a lower rate of smokers in this large group of celiac disease patients compared to the general population. Differences in presenting symptoms and higher age at diagnosis suggest that smoking might influence disease onset and/or presentation in an early phase.