

The relationship between vitamin D status and allergic diseases in New Zealand preschool children (289)

Carolyn T Cairncross 1 , Cameron C Grant 2 , Welma Stonehouse 3 , Cath A Conlon 1 , Barry McDonald 1 , Lisa A Houghton 4 , Darryl Eyles 5 , Carlos Camargo, Jnr 6 , Jane Coad 1 , Pamela R von Hurst 1
  1. Massey University, Auckland, New Zealand
  2. University of Auckland, Auckland, New Zealand
  3. CSIRO, Adelaide, Australia
  4. University of Otago, Dunedin, New Zealand
  5. University of Queensland, Brisbane, Australia
  6. Massachusetts General Hospital, Boston, USA

Background/Aims: Historically, research on vitamin D deficiency in young children focussed on bone development and rickets. Growing awareness of the immunomodulatory effects of vitamin D has led to the investigation of the relations of vitamin D status to many allergic diseases. Our objective was to investigate this topic in preschool-aged children in NZ.

Methods: Dried capillary blood spots were collected from 1329 children during late winter to early spring for 25(OH)D measurement by LC-MS/MS. Caregivers completed a questionnaire about their child’s  recent medical history. Modules of the validated International Study of Asthma and Allergies in Childhood questionnaire were used to identify eczema, allergic rhinoconjunctivitis (ARC) and asthma; diagnosis of doctor-diagnosed food allergy was by parental report. Analysis was by multivariable logistic regression.

Results: Mean 25(OH)D concentration was 52 (SD 19) nmol/L, with 7% of children <25nmol/L and 49% <50nmol/L. Children with 25(OH)D concentrations ≥75nmol/L (n=29) had a two-fold increased risk for parent-report of doctor-diagnosed food allergy compared to children with 25(OH)D 50-74nmol/L (OR=2.21, 1.33-3.68, P=0.002). There was a non-significant U-shaped association between 25(OH)D and ARC, with a nadir at approximately 60nmol/L. No associations were present between 25(OH)D concentration and presence of parent-reported eczema or asthma.

Conclusions: Vitamin D deficiency was not associated with several allergic diseases in these NZ preschool children. In contrast, high 25(OH)D concentrations were associated with a two-fold increased risk of food allergy, with a trend of higher risk of ARC following a U-shaped association with 25(OH)D.

Funding source: Health Research Council of New Zealand