Celiac Disease Risk Climbs If Gluten Is Introduced After Age Six Months

October 15, 2013

By Will Boggs, MD

NEW YORK (Reuters Health) Oct 15 - Introduction of gluten after six months of age is associated with an increased risk of celiac disease, researchers from Norway report.

"This is in line with findings from a previous study on a high-risk cohort from the US," Dr. Ketil Stordal from the Norwegian Institute of Public Health in Oslo told Reuters Health. "There does not seem to be any reason to avoid gluten introduction before six months; rather a time window for optimal introduction is from four to six months of age."

In earlier studies, introduction of gluten early (before four months) or late (after six months) was associated with increased risk of celiac disease, whereas breastfeeding and low dose of gluten at introduction were associated with lower risk of celiac disease.

In this study, breastfeeding wasn't protective, however.

Dr. Stordal and colleagues used data from the Norwegian Mother and Child Cohort Study (MoBa) to analyze the association between timing of gluten introduction, breastfeeding, and the risk of celiac disease.

The study included 324 children with celiac disease and 81,843 cohort controls followed for up to six months, and 287 children with celiac disease and 67,628 cohort controls followed for up to 18 months.

As reported October 7 online in Pediatrics, similar percentages of children had gluten introduced at five or six months (45.3%) and after six months (46.6%), with 8.0% receiving gluten by four months of age. Just over three quarters of the mothers (78.1%) were still breastfeeding when the babies were six months old.

The incidence of celiac disease was 3.68 per 1000 of infants who were introduced to gluten at five or six months, compared with 4.24 per 1000 among infants who received gluten at or before four months. The rate was 4.15 per 1000 when gluten was started after six months.

In adjusted models, introduction of gluten after six months was associated with a 27% increased risk of celiac disease, whereas early introduction of gluten was not associated with increased risk of celiac disease.

For children breastfed more than 12 months, the risk of celiac disease was 59% higher (although the difference was not statistically significant) for those introduced to gluten after six months.

In adjusted analyses, infants breastfed more than 12 months were 49% more likely than those breastfed less than six months to develop celiac disease. There was no association between breastfeeding for six to 12 months and celiac disease risk.

In another subgroup analysis, the risk of celiac disease among children introduced to gluten at six months of age was highest in those breastfed more than a month after gluten introduction, but again, the difference was not statistically significant.

"Our findings could not support any reduced risk with breastfeeding, neither alone or during introduction of gluten," Dr. Stordal said. "We do not think that prolonged breastfeeding > 12 months is increasing the risk; this finding could be attributable to even more delayed gluten introduction or to reasons for prolonged breastfeeding not detectable in our data."

"Causality remains to be proven," Dr. Stordal said, "and definitive recommendations should ideally be based on randomized controlled trials, similar to the multicenter study expected from Europe within a few months."

"We do for now have a limited understanding of environmental factors impacting on the risk of celiac disease outside the presence of gluten in the diet," Dr. Stordal explained. "There are lines of evidence pointing to early events during pregnancy and infancy as critical for the risk of immune-mediated and autoimmune diseases, but these remain to be identified."

SOURCE: https://bit.ly/17GKrxA

Pediatrics 2013.


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