Effect of the time of gluten introduction on the development of CD
| Reference | Age of gluten introduction | Effect size | GRADE score | Bias risk |
|---|---|---|---|---|
| Retrospective studies | ||||
| Fälth-Magnusson et al19 | Mean age at gluten introduction: 6-month for CD cases 6.1 for controls | Range 4–7 Range 4–10 p NS | 2 | High |
| Peters et al23 | Continuous risk per month (1–12 months) <3 vs >3 months 3 vs 4 months 4 vs 5 months >5 months | HR 0.98 (95% CI 0.86 to 1.11) HR 0.72 (95% CI 0.29 to 1.79) HR 0.52 (95% CI 0.18 to 1.44) HR 1.21 (95% CI 0.40 to 3.68) HR 0.72 (95% CI 0.28 to 1.85) | 1 | High |
| Prospective studies | ||||
| Ivarsson et al21 | 1–4 months 5–6 months (reference) 7–12 months | HR 1.4 (95% CI 0.87 to 2.4) HR 0.76 (95% CI 0.41 to 1.4) | 2 | High |
| Ziegler et al14 | <3 months 3–6 months (reference) >6 months | HR 2.3 (95% CI 0.3 to 18.2) HR 0.7 (95% CI 0.3 to 1.8) | 3 | Medium |
| Norris et al15 | 1–3 months 3–4 months (reference) >7 months | HR 5.17 (95% CI 1.44 to 18.57) HR 1.87 (95% CI 0.97 to 3.60) | 3 | Medium |
| Welander et al22 | 3–4 months 5–6 months (reference) 7–8 months | HR 1.0 (95% CI 0.3 to 3.3) HR 1.1 (95% CI 0.6 to 2.0) | 3 | High |
| Størdal et al26 | <4 months 5–6 months (reference) >6 months | OR 1.27 (95% CI 1.01 to 1.65) OR 1.05 (95% CI 0.69 to 1.58) | 3 | High |
| Jansen et al27 | >6 months | NS | 3 | Medium |
| Vriezinga et al13 | 16–24 weeks | HR 1.23 (95% CI 0.79 to 1.91) | 4 | Low |
| Lionetti et al12 | 6 vs 12 months | HR 0.9 (95% CI 0.6 to 1.4) | 4 | Low |
| Aronsson et al16 | <17 weeks 17–26 (reference) >26 weeks | HR 0.59 (95% CI 0.33 to 1.04) HR 0.90 (95% CI 0.69 to 1.18) | 3 | Medium |
CD, celiac disease; NS, not significant.