BACKGROUND: Environmental risk factors playing a causative role in Crohn's 
Disease (CD) remain largely unknown. Recently, it has been suggested that 
refrigerated food could be involved in disease development. We thus conducted a 
pilot case control study to explore the association of CD with the exposure to 
domestic refrigeration in childhood.
METHODOLOGY/PRINCIPAL FINDINGS: Using a standard questionnaire we interviewed 
199 CD cases and 207 age-matched patients with irritable bowel syndrome (IBS) as 
controls. Cases and controls were followed by the same gastroenterologists of 
tertiary referral clinics in Tehran, Iran. The questionnaire focused on the date 
of the first acquisition of home refrigerator and freezer. Data were analysed by 
a multivariate logistic model. The current age was in average 34 years in CD 
cases and the percentage of females in the case and control groups were 
respectively 48.3% and 63.7%. Patients were exposed earlier than controls to the 
refrigerator (X2 = 9.9, df = 3, P = 0.04) and refrigerator exposure at birth was 
found to be a risk factor for CD (OR = 2.08 (95% CI: 1.01-4.29), P = 0.05). 
Comparable results were obtained looking for the exposure to freezer at home. 
Finally, among the other recorded items reflecting the hygiene and comfort at 
home, we also found personal television, car and washing machine associated with 
CD.
CONCLUSION: This study supports the opinion that CD is associated with exposure 
to domestic refrigeration, among other household factors, during childhood.