# Bone structure and body composition in adolescents with cow’s milk allergy in infancy: a clinical cohort study

## TL;DR

Adolescents with a confirmed cow's milk allergy in infancy may have lower bone density compared to peers without the allergy.

## Contribution

This study identifies a potential link between cow's milk allergy in infancy and reduced volumetric bone mineral density in adolescence.

## Key findings

- CMA-confirmed adolescents had lower radial vBMD compared to CMA-refuted peers.
- CMA-confirmed adolescents had lower tibial vBMD compared to controls.
- No differences in body composition were observed between the groups.

## Abstract

We compared bone structure and body composition in adolescents with a challenge-confirmed cow’s milk allergy (CMA) during infancy to peers with refuted CMA and to controls.

An observational clinical cohort study.

A tertiary allergy clinic at Helsinki University Hospital.

From a randomised controlled trial from 1999 to 2001 evaluating the effect of probiotics on atopic eczema, we followed up participants (n=81) at 15–18 years’ age and recruited age-matched controls (n=49). Original study participants all had atopic eczema, and CMA confirmed (n=43) or refuted (n=38) by double-blind placebo-controlled cow’s milk challenge in infancy.

The primary outcome was differences in volumetric bone mineral density (vBMD) measured with peripheral quantitative CT. Secondary outcomes were differences in body composition by a bioelectric impedance analysis.

Participant’s median age was 17.3 years, 62% were females. After adjusting for sex, age-adjusted body mass index, past 5 years’ mean daily supervised physical activity, daily vitamin D intake from food and supplements and mean daily intake of dairy products, the CMA-confirmed group had, compared with the CMA-refuted group, lower median total vBMD at the distal radius (Z-scores −1.49 vs −0.78). The CMA-confirmed group had lower median total vBMD (Z-scores −0.05 vs +0.01) and lower median trabecular vBMD (Z-scores +0.20 vs +0.51) at the distal tibia compared with controls. No group differences in body composition were found.

An early childhood history of CMA may be associated with lower adolescent radial and tibial vBMD. Further studies are needed to assess this potential association.