Table 4:

Stratified analysis of mean number of cases per day and incidence rate ratio for peanut-induced anaphylaxis

CharacteristicRest of year; no. of cases per day (95% CI)HalloweenChristmasEaster
No. of cases per day (95% CI)IRR (95% CI)*No. of cases per day (95% CI)IRR (95% CI)*No. of cases per day (95% CI)IRR (95% CI)*
Sex
 Female0.08 (0.07–0.09)0.16 (0.07–0.33)1.92 (0.91–4.08)0.04 (0.01–0.18)0.55 (0.14–2.21)0.09 (0.03–0.24)1.10 (0.41–2.95)
 Male0.13 (0.12–0.14)0.24 (0.14–0.44)1.90 (1.04–3.45)0.09 (0.03–0.24)0.69 (0.26–1.85)0.24 (0.14–0.44)1.90 (1.04–3.45)
Age, yr
 < 60.12 (0.11–0.13)0.18 (0.09–0.36)1.52 (0.75–3.06)0.02 (0.00–0.16)0.19 (0.03–1.35)0.09 (0.03–0.24)0.76 (0.28–2.03)
 ≥ 60.09 (0.08–0.10)0.22 (0.12–0.41)2.40 (1.28–4.51)0.11 (0.05–0.27)1.20 (0.50–2.91)0.24 (0.14–0.44)2.64 (1.45–4.82)
Recruitment method
 Retrospective0.12 (0.11–0.13)0.27 (0.15–0.47)2.26 (1.27–4.02)0.13 (0.06–0.30)1.13 (0.50–2.53)0.09 (0.03–0.24)0.75 (0.28–2.02)
 Prospective0.09 (0.08–0.10)0.13 (0.06–0.30)1.45 (0.65–3.26)0.00.00.24 (0.14–0.44)2.66 (1.46–4.86)
History of asthma
 Yes0.03 (0.03–0.04)0.09 (0.03–0.34)2.56 (0.94–6.94)0.04 (0.01–0.18)1.28 (0.32–5.18)0.09 (0.03–0.34)2.56 (0.94–6.94)
 No0.17 (0.16–0.19)0.31 (0.18–0.53)1.79 (1.06–3.05)0.09 (0.03–0.24)0.51 (0.19–0.37)0.24 (0.14–0.44)1.41 (0.78–2.56)
Severity of reaction
 Mild0.04 (0.04–0.05)0.09 (0.03–0.24)2.06 (0.76–5.56)0.02 (0.00–0.16)0.51 (0.07–3.68)0.00.0
 Moderate0.15 (0.14–0.17)0.29 (0.17–0.50)1.87 (1.08–3.24)0.09 (0.03–0.24)0.57 (0.21–1.54)0.29 (0.17–0.50)1.87 (1.08–3.24)
 Severe0.01 (0.01–0.2)0.02 (0.00–0.16)1.85 (0.25–13.48)0.02 (0.00–0.16)1.85 (0.25–13.48)0.04 (0.01–0.18)3.70 (0.89–15.35)
Hospital centre
 MCH0.14 (0.13–0.15)0.33 (0.20–0.55)2.41 (1.44–4.04)0.11 (0.05–0.27)0.80 (0.33–1.94)0.16 (0.07–0.33)1.13 (0.53–2.38)
 BCCH0.04 (0.03–0.05)0.02 (0.00–0.16)0.58 (0.08–4.19)0.02 (0.00–0.16)0.58 (0.08–4.19)0.04 (0.01–0.18)1.17 (0.29–4.73)
  • Note: BCCH = British Columbia Children’s Hospital, CI = confidence interval, IRR = incidence rate ratio, MCH = Montreal Children’s Hospital.

  • * Calculated with rest of year as reference category.

  • Value is 1.89 E–11.

  • Confidence interval is indeterminately large.