Background: Celiac disease (CD) prevalence has increased significantly in recent decades in some developed countries. Yet the environmental factors in the existing literature do not appear to provide a satisfactory explanation for this increase. Objective: To determine whether nine variables are associated with CD in children. These variables are: incidence of ear infection before 2 years old, courses of antibiotics before 2 years old, duration of breastfeeding, vitamin D drop exposure in infancy, vitamin D supplement exposure between 2-3 years old, age at gluten introduction into the diet, fat content of cow's milk consumed between 2-3 years old, quantity of cow's milk consumed between 2-3 years old, and type of water consumed at 2 years old. Methods: An Internet-based survey was conducted among parents living in the US with at least one biological child between 3 and 12 years old. Potential participants were informed about the survey through social media, websites, electronic newsletters, and advertisements. Results: After exclusions, there remained 332 responses associated with children with CD (cases), and 241 responses associated with children who do not have CD (controls). In this data set, skim milk as the primary form of liquid cow's milk consumed between 2-3 years old (adjusted odds ratio [aOR]=3.556, CI=1.430-10.22, P=0.010), vitamin D drops administered for more than 3 months (aOR=1.749, CI=1.079-2.872, P=0.025), courses of antibiotics (aOR=1.133, CI=1.037-1.244, P=0.007), and incidence of ear infection (aOR=1.183, CI=1.041-1.348, P=0.010) are all associated with CD in children. Conclusions: This study is the first to find an association between skim milk consumption and CD and vitamin D drop use for greater than 3 months and CD. It also adds to evidence that early life exposure to antibiotics and early life infection, specifically ear infection, are associated with CD.
Keywords: antibiotic; coeliac; ear infection; epidemiology; gluten; milk; vitamin D.