Objective To examine whether the timing of gluten introduction and breastfeeding duration are associated with subclinical celiac disease in children at the age of 6 years.
Methods This study was embedded in the Generation R study, a population-based prospective cohort study. Participants included 1679 Dutch children positive for HLA-DQ2/DQ8. Data on the timing of gluten introduction (<6 months vs. ≥6 months) and duration of breastfeeding (<6 months vs. ≥6 months) were obtained by questionnaire. Serum samples were analysed for anti-tissuetransglutaminase (tTG) levels at age 6 years. Anti-tTG levels were categorised into negative (≤7 U/ml) and positive (>7 U/ml) levels. Positive anti-tTG levels were further categorised based on the ≥10 times upper limit of normal (ULN) levels of the test kit (>7–70 U/ml and ≥70 U/ml). Multivariable logistic regression analyses were performed.
Results Positive anti-tTG levels were found in 43 children of which 26 children had levels above the 10 times ULN (≥70 IU/ml). The introduction of gluten from the age of 6 months onwards and breastfeeding for 6 months or longer were not significantly associated with positive anti-tTGlevels. In addition, the timing of gluten introduction and duration of breastfeeding were not significantly associated with positive anti-tTG levelsbelow and above the 10 times ULN.
Conclusions Delayed introduction of gluten beyond the age of 6 months does not increase the risk of subclinical CD. Also, breastfeeding for 6 months or longer does not decrease the risk of subclinical CD in children at 6 years of age.