Pre-Diagnosis Dietary Pattern Differences in Australian Children with Inflammatory Bowel Disease: Exposure Across Ethnicities

Background/Objectives: The pre-diagnosis dietary intake in newly diagnosed multi-ethnic paediatric inflammatory bowel disease (PIBD) is not well understood. This study aimed to describe the pre-diagnosis diet and environmental factors in children with newly diagnosed PIBD attending a single Australian tertiary children’s hospital. Methods: A pilot cross-sectional study was conducted from February 2022 to February 2023 involving children with newly diagnosed PIBD. Results: Of 56 children confirmed with PIBD, 54% had Crohn’s disease (CD)—mean ± SD age, 11.55 years ± 2.84—and 46% had Ulcerative Colitis (UC)—11.50 years ± 2.94 (45%, non-Caucasian). More Caucasians had an IBD family history (48.3% vs. 20%; p = 0.02 *). Non-Caucasian children demonstrated significantly lower mean serum vitamin D levels than Caucasian children (42.5 vs. 69 nmol/L; p ≤ 0.001 ***). Most children across ethnicities for both IBD subtypes had ‘regular’ intakes of red meat, whereas more Caucasian children had ‘regular’ intakes of processed/deli meat (72% vs. 39%; p = 0.02 *). A total of 64% of non-Caucasian children with CD reported a usual pre-diagnosis diet that differed from the traditional diet, compared to 42% with UC (p = 0.29). When eating out, fast foods were chosen regularly by most children with PIBD. Pre-diagnosis dietary intake data indicated that most with PIBD ‘rarely/never’ had whole-food sources of plant protein and had ‘infrequent’ intake of rice. Plant food diversity was low (mean 11 types/week). Conclusions: The significantly lower likelihood of IBD family history, along with relatively lower vitamin D levels, and the predominance of a Western-style dietary pattern among non-Caucasian children are compatible with the hypothesis that non-genetic factors may be important in PIBD, warranting further investigation into diet and environmental factors in this group. Further investigation of the pre-disease modifiable non-genetic factors contributing to the development of PIBD in the migrant population group is recommended. The finding across ethnicities of low pre-diagnosis plant food diversity was novel; however, due to the lack of healthy controls and the use of a novel but non-validated exposome tool, causality associations should be interpreted cautiously.