The burden of celiac disease (CD) is increasingly recognized as a global problem. However, whether this situation depends on genetics or environmental factors is uncertain. The authors examined these aspects in Sweden, a country in which the risk of CD is generally considered to be high. If environmental factors are relevant, CD risk in second-generation immigrant children should be related to maternal length of stay in Sweden before delivery.
Linking the Swedish Medical Birth Registry to other national registries, the authors investigated all singleton children (n = 792,401) born in Sweden between 1987 and 1993. They studied the risk of CD in children before age 6 as a function of the mother's geographical region of birth and length of stay in Sweden before delivery using Cox regression models.
In children whose mothers immigrated to Sweden from a country outside of Europe, a maternal length of stay in Sweden of more than 5 years increased the hazard ratio (HR) of CD (1.73, 95% confidence interval (CI) 1.06-2.81). The authors observed a similar result among children born to mothers from a Nordic country outside of Sweden (HR 1.57, 95% CI 0.89-2.75), but a non-conclusive protective effect was observed in second-generation immigrant children from a non-Nordic European country (HR 0.65, 95% CI 0.39-1.09).
The risk of CD among second-generation immigrants seems to be conditioned by maternal length of stay in Sweden before delivery, suggesting that environmental factors contribute to the variation in CD risk observed across populations.