On the one hand, it makes total sense to me that childhood antibiotics could mess up your digestive tract immune system. On the other hand:
"Subgroup analysis showed that antibiotic use <18 years old was a risk factor for CD development in the Chinese (adjusted OR 4.80, 95% CI 1.62–12.24; P = 0.005) but not in Australian populations (OR 1.80, 95% CI 0.33–9.95; P = 0.498)."
If it were a robust finding, it would not fall apart on subgroup analysis.
Actually the reverse, we should be skeptical of subgroup analyses, because they are often fishing for results, have issues with multiple comparisons, and are typically underpowered.
"Subgroup analysis showed that antibiotic use <18 years old was a risk factor for CD development in the Chinese (adjusted OR 4.80, 95% CI 1.62–12.24; P = 0.005) but not in Australian populations (OR 1.80, 95% CI 0.33–9.95; P = 0.498)."
If it were a robust finding, it would not fall apart on subgroup analysis.