Table 6.
Explanatory variables in intussusception cases (BC level 1) and matched controls; comparison among study groups (n = 388)
| Exposure | Cases (n = 116) n/N (%) | Population-based controls (n = 272) n/N (%) |
Univariate matcheda logistic regression analysis (OR + 95% CI, p value) |
|---|---|---|---|
| Complications during pregnancy | 35/116 (30.2) | 73/272 (26.8) | 1.13 (0.70–1.83) p = .6050 |
| Complications during childbirth | 47/116 (40.5) | 95/272 (34.9) | 1.20 (0.76–1.90) p = .4326 |
| Preterm birth (birth at fewer than 37 weeks gestational age) | 4/113 (3.5) | 9/270 (3.3) | 0.84 (0.25–2.81) p = .7718 |
| Low birthweight (<2500 g) | 1/116 (0.9) | 11/272 (4.0) | 0.15 (0.02–1.23) p = .0779 |
| High birthweight (>4200 g) | 5/116 (4.3) | 16/272 (5.9) | 0.70 (0.25–1.97) p = .5033 |
| Small (< gender-specific 10th percentileb) for gestational age | 10/113 (8.9) | 25/270 (9.3) | 0.92 (0.42–2.01) p = .8279 |
| Large (> gender-specific 90th percentileb) for gestational age | 10/113 (8.9) | 23/270 (8.5) | 0.89 (0.40–1.98) p = .7658 |
| Breastfeeding$ at the month of index date* | 50/116 (43.1) | 162/272 (59.6) | 0.52 (0.33–0.84) p = .0074 |
| Formula milk$ at the month of index date* | 53/114 (46.5) | 99/265 (37.4) | 1.41 (0.89–2.24) p = .1408 |
| Supplementary food$ at the month of index date* | 93/116 (80.2) | 204/271 (75.3) | 1.55 (0.75–3.20) p = .2420 |
| Food intolerance in the first year of life$ | 4/113 (3.5) | 13/267 (4.9) | 0.66 (0.21–2.07) p = .4754 |
| Food allergy in the first year of life$ | 2/111 (1.8) | 6/268 (2.2) | 0.73 (0.14–3.68) p = .6997 |
| Surgery prior to index date* | 3/99 (3.03) | 5/271 (1.85) | 1.28 (0.27–5.98) p = .7580 |
| Family history of intussusception | 9/113 (8.0) | 6/271 (2.2) | 3.47 (1.18–10.18) p = .0235 |
n number of participants exposed; N total number of participants with available information; BC Brighton Collaboration criteria for intussusception; *index date cases: date of symptom onset, controls: day of life on which the matching case experienced first symptoms of intussusception; $according to information obtained from parents within the scope of a standardized telephone interview; amatched by gender, date of birth (± 30 calendar days), federal state, and place of residence (first digit of the zip code); baccording to Voigt et al.58