TY - JOUR

T1 - Effect of probiotics on thymus size and markers of infection in late infancy: a randomized controlled trial

AU - Larnkjær, Anni

AU - Michaelsen, Kim F.

AU - Rytter, Maren Johanne Heilskov

AU - Mølgaard, Christian

AU - Laursen, Rikke Pilmann

N1 - CURIS 2021 NEXS 102

PY - 2021

Y1 - 2021

N2 - Background: Probiotics are known to stimulate the immune system but the effect on thymus size in late infancy is unknown. We examined the effect of probiotics on thymus size and C-reactive protein (CRP) in healthy Danish infants starting daycare. We further examined associations between thymus size, CRP and recent infections.Methods: The study included 186 children randomized to a combination of Lactobacillus rhamnosus, LGG® and Bifidobacterium animalis spp. lactis, BB-12® or placebo for 6 months. Thymus size, assessed as thymus index (TI) and thymus weight index (TWI), was measured by ultrasound at baseline and at endpoint. Blood samples were drawn to measure CRP. Infections were parent-reported.Results: There was no significant difference in thymus size between the probiotic group and placebo (p ≥ 0.248) but TWI tended to be higher in the probiotic group corresponding to 5% higher than placebo (p = 0.068) in an adjusted model. There was no effect of probiotics on CRP (p = 0.331). At the endpoint, thymus size was inversely associated with CRP (p ≤ 0.040), diarrhea (p ≤ 0.050), and TI was also associated with the absence from daycare due to respiratory or gastrointestinal infections (p = 0.010).Conclusion: The probiotic intervention had no effect on thymus size or CRP in Danish children at the age of starting daycare.Impact: Overall there was no effect on thymus size of a combination of Lactobacillus rhamnosus, LGG® and Bifidobacterium animalis spp. lactis, BB-12® administered to Danish children starting daycare.This study examines the effect of probiotics on thymus size in healthy children when they start daycare thus exposed for infections while their immune system is still developing. This has to our knowledge not been described before.We found no significant difference in thymus size between the probiotic and placebo groups, but for thymus weight index, there was a trend. This should be investigated further in studies designed for this as primary outcome.

AB - Background: Probiotics are known to stimulate the immune system but the effect on thymus size in late infancy is unknown. We examined the effect of probiotics on thymus size and C-reactive protein (CRP) in healthy Danish infants starting daycare. We further examined associations between thymus size, CRP and recent infections.Methods: The study included 186 children randomized to a combination of Lactobacillus rhamnosus, LGG® and Bifidobacterium animalis spp. lactis, BB-12® or placebo for 6 months. Thymus size, assessed as thymus index (TI) and thymus weight index (TWI), was measured by ultrasound at baseline and at endpoint. Blood samples were drawn to measure CRP. Infections were parent-reported.Results: There was no significant difference in thymus size between the probiotic group and placebo (p ≥ 0.248) but TWI tended to be higher in the probiotic group corresponding to 5% higher than placebo (p = 0.068) in an adjusted model. There was no effect of probiotics on CRP (p = 0.331). At the endpoint, thymus size was inversely associated with CRP (p ≤ 0.040), diarrhea (p ≤ 0.050), and TI was also associated with the absence from daycare due to respiratory or gastrointestinal infections (p = 0.010).Conclusion: The probiotic intervention had no effect on thymus size or CRP in Danish children at the age of starting daycare.Impact: Overall there was no effect on thymus size of a combination of Lactobacillus rhamnosus, LGG® and Bifidobacterium animalis spp. lactis, BB-12® administered to Danish children starting daycare.This study examines the effect of probiotics on thymus size in healthy children when they start daycare thus exposed for infections while their immune system is still developing. This has to our knowledge not been described before.We found no significant difference in thymus size between the probiotic and placebo groups, but for thymus weight index, there was a trend. This should be investigated further in studies designed for this as primary outcome.

U2 - 10.1038/s41390-020-0895-5

DO - 10.1038/s41390-020-0895-5

M3 - Journal article

C2 - 32305995

VL - 89

SP - 563

EP - 568

JO - Pediatric Research

JF - Pediatric Research

SN - 0031-3998

IS - 3

ER -