Objectives: It has been suggested that environmental factors other than gliadin might play a role in pathogenesis of celiac disease. Cigarette smoking was reported to exert a protective effect against the development of symptomatic celiac disease; however, this relationship was not confirmed. The aim of this study was to determine the effect of cigarette smoking on celiac disease.
Methods: A cohort of 87 consecutive celiac disease patients attending the clinic of Malabsorption and 174 age- and sex-matched individuals diagnosed with functional GI disorder were included in the study. Clinical information was obtained both at the time of diagnosis and at follow-up by reviewing the clinical history. Smoking information was obtained through an in-person interview using a questionnaire.
Results: Although 33% of controls were current smokers at the time of the study, only 16% of celiac patients were smokers at diagnosis (odds ratio, 0.39; 95% confidence interval 0.19-0.79; p < 0.006). The proportion of nonsmokers among patients (84%) was significantly greater than that among controls (67%; odds ratio, 2.54; 95% confidence interval 1.27-5.16; p < 0.007). Current smoker patients had a lower baseline BMI (p < 0.05) and body weight (p < 0.05) compared to former smokers. Compared with nonsmokers, control individuals who were active smokers at entry in the study were younger (p < 0.02) and had lower body weight (p < 0.03) and BMI (p < 0.03). Interestingly, positive lineal correlation was observed between age at diagnosis and daily cigarette consumption (r = 0.72; p < 0.004) in active smokers. We did not detect any relationship either between causes for cessation of smoking and clinical symptoms or between differences in the proportions of smoking habits when patients were stratified according to their clinical status at diagnosis (symptomatic vs subclinical/asymptomatic cases).
Conclusions: This study provides evidence that, compared with control subjects, a significantly lower proportion of patients with celiac disease were current smokers at the time of diagnosis, and that cigarette smoking delayed diagnosis of celiac disease. Our study suggests that the nutritional compromise of patients with celiac disease who smoked resulted from the summation of the effect of celiac disease per se and that produced by the smoking habit. Further studies are necessary to identify whether the relationship between smoking and celiac disease is causal or incidental.