Background
Methods
Study design
Food hypersensitivity definitions
Control infants
Statistical analysis
Results
Participants
All participants | Lost to follow up (2 years) | Eligible for DBPCFC | |||
---|---|---|---|---|---|
Not challenged | Challenged | Confirmed food hypersensitivity | |||
n | 1140 | 317 | 15 | 55 | 41 |
Baseline characteristics | |||||
Caucasian ethnicity | 1093 (95.8 %) | 304 (96.0 %) | 11 (73.3 %) | 50 (90.9 %) | 39 (95.1 %) |
Smoking during pregnancy | 70 (6.1 %) | 45 (14.2 %) | 0 (0.0 %) | 1 (1.8 %) | 1 (2.4 %) |
Mothers’ mean age, years | 31.9 (5.2) | 30.0 (5.8) | 31.9 (5.2) | 32.0 (5.5) | 31.6 (5.3) |
Fathers’ mean age, years | 34.1 (5.7) | 32.6 (6.4) | 33.9 (5.1) | 33.9 (4.5) | 33.2 (4.6) |
Highest education of parents | |||||
Low (up to 12y) | 220 (19.3 %) | 86 (27.2 %) | 4 (26.7 %) | 9 (16.4 %) | 7 (17.1 %) |
Intermediate (>12 years, e.g. college) | 331 (29.0 %) | 96 (30.2 %) | 3 (20.0 %) | 19 (34.5 %) | 13 (31.7 %) |
High (e.g. university) | 565 (49.6 %) | 121 (38.3 %) | 8 (53.3 %) | 27 (49.1 %) | 21 (51.2 %) |
Allergies in family | |||||
Maternal atopy (A, AR or E) | 765 (67.1 %) | 210 (66.4 %) | 13 (86.7 %) | 48 (87.3 %) | 36 (87.8 %) |
Paternal atopy (A, AR or E) | 610 (53.5 %) | 170 (53.7 %) | 11 (73.3 %) | 30 (54.5 %) | 23 (56.1 %) |
Maternal food hypersensitivity | 249 (21.8 %) | 77 (24.4 %) | 6 (40.0 %) | 13 (23.6 %) | 11 (26.8 %) |
Paternal food hypersensitivity | 135 (11.8 %) | 35 (11.1 %) | 1 (6.7 %) | 7 (12.7 %) | 6 (14.6 %) |
Urban living environment | 273 (23.9 %) | 99 (31.2 %) | 6 (40.0 %) | 11 (20.0 %) | 8 (19.5 %) |
Mean number of sibs at home | 1.7 (0.88) | 1.8 (0.99) | 1.4 (0.65) | 1.6 (0.71) | 1.5 (0.64) |
Female sex | 557 (48.9 %) | 166 (52.4 %) | 6 (40.0 %) | 23 (41.8 %) | 17 (41.5 %) |
Animals in household at birth | |||||
Any | 566 (49.6 %) | 164 (50.6 %) | 8 (53.3 %) | 33 (60.0 %) | 26 (63.4 %) |
Cat | 325 (28.5 %) | 92 (28.4 %) | 4 (26.6 %) | 15 (27.3 %) | 10 (24.4 %) |
Dog | 204 (17.9 %) | 66 (20.4 %) | 3 (20.0 %) | 15 (27.3 %) | 13 (31.7 %) |
Season of birth (n = 1139) | |||||
Summer | 379 (33.3) | 112 (34.6 %) | 2 (13.3 %) | 21 (38.2 %) | 17 (41.5 %) |
Autumn | 251 (22.0) | 66 (20.4 %) | 7 (46.6 %) | 13 (23.6 %) | 8 (19.5 %) |
Winter | 183 (16.1) | 51 (15.7) | 2 (13.3 %) | 9 (16.4 %) | 8 (19.5 %) |
Spring | 326 (28.6) | 95 (29.3 %) | 4 (26.6 %) | 11 (20.0 %) | 8 (19.5 %) |
Cumulative incidence of food hypersensitivity
Characteristics of participants with food hypersensitivity
Participants with food hypersensitivity (n = 41) | Control participants (n = 82) | p value | |
---|---|---|---|
Median (IQR) age of child, months | 9.3 (5.7–17.0) | 14.9 (10.1–20.2) | 0.024 |
Diagnostic criteria: positive DBPCFC | 41 (100 %) | ||
History of anaphylaxis | 0 (0 %) | ||
Presenting symptoms | |||
Gastrointestinal | 11 (26.8 %) | ||
Cutaneous (eczema and/or urticaria) | 22 (46.3 %) | ||
Respiratory | 4 (9.7 %) | ||
Other | 3 (7.3 %) | ||
None | 1 (2.4 %) | ||
How soon did symptoms appear, minutes (SE) [Range] | 170 (118) [0–4320] | ||
Positive specific IgE (≥0.35 kU/l) | 21 (51.2 %) | ||
Median specific IgE, kU/l | 1.85 (0.85–3.81) | ||
Positive SPT (≥3 mm) | 17 (41.4 %) | ||
Median SPT weal diameter, mm | 5.00 (3.00–6.25) | ||
Eczema | 32 (78.1 %) | 45 (54.9 %) | 0.005 |
Wheeze | 17 (41.5 %) | 21 (25.6 %) | 0.054 |
Rhinitis | 14 (34.1 %) | 11 (13.4 %) | 0.007 |
Potential risk factors for food hypersensitivity
Participants with food hypersensitivity (n = 41) | Control participants (n = 82) | p value | |
---|---|---|---|
Maternal atopy | 36 (87.8 %) | 52 (63.4 %) | 0.002 |
Paternal atopy | 23 (57.5 %) | 50 (61.0 %) | 0.844 |
Mean maternal pre-pregnancy weight, kg | 65.9 (14.0) | 64.0 (11.5) | 0.558 |
Mean maternal pre-pregnancy height, cm | 164.1 (5.9) | 165.0 (6.6) | 0.690 |
Median parity | 0.0 (0.0–1.0) | 0.0 (0.0–1.0) | 0.729 |
Singleton pregnancy | 40 (97.6 %) | 82 (100.0 %) | 0.333 |
Maternal smoking in pregnancy | 1 (2.4 %) | 3 (3.7 %) | 1.000 |
Other household smoking in pregnancy | 8 (19.5 %) | 5 (6.1 %) | 0.027 |
Aspirin/paracetamol during pregnancy | 30 (81.1 %) | 49 (69.0 %) | 0.132 |
Any anti-inflammatory during pregnancy | 4 (11.1 %) | 7 (9.9 %) | 0.542 |
Maternal antibiotics during pregnancy | 9 (22.0 %) | 19 (23.3 %) | 0.286 |
Mode of delivery | |||
Normal | 20 (51.3 %) | 37 (45.7 %) | 0.860 |
Caesarean | 13 (31.7 %) | 20 (24.4 %) | |
Forceps | 3 (7.3 %) | 12 (14.8 %) | |
Mean gestation, weeks | 39.5 (1.7) | 40.0 (1.4) | 0.062 |
Mean birth weight, grams | 3480 (470) | 3370 (562) | 0.913 |
Antibiotics in first week of age | 0 (0.0 %) | 0 (0.0 %) | 1.000 |
Environmental | |||
Urban living Environment | 8 (19.5 %) | 11 (13.4 %) | 0.601 |
Live on a main road | 3 (7.3 %) | 5 (6.1 %) | 0.535 |
Cat at home | 10 (24.4 %) | 24 (29.3 %) | 0.365 |
Dog at home | 13 (31.7 %) | 12 (14.6 %) | 0.026 |
Mould in home | 5 (12.2 %) | 8 (9.8 %) | 0.457 |
Type of flooring where baby sleeps | |||
Carpet | 37 (90.2 %) | 72 (87.8 %) | 0.757 |
Wooden, laminate or parquet | 4 (9.8 %) | 9 (11.0 %) | |
Linoleum or vinyl tiles | 0 (0.0 %) | 1 (1.2 %) | |
Type of mattress your baby sleeps on | |||
Foam | 29 (70.7 %) | 51 (62.2 %) | 0.362 |
Synthetic | 10 (24.4 %) | 22 (26.8 %) | |
Other | 2 (4.9 %) | 9 (11.0 %) | |
Cleaning kitchen work surfaces | |||
Non-bactericidal | 12 (29.3 %) | 27 (32.9 %) | 0.396 |
Bactericidal | 27 (65.9 %) | 50 (61.0 %) | |
Neither | 1 (2.4 %) | 5 (6.1 %) | |
Do not know | 1 (2.4 %) | 0 (0.0 %) | |
Cleaning table where you eat | |||
Spray cleaner | 26 (63.4 %) | 38 (46.3 %) | 0.131 |
Soap and Water | 10 (24.4 %) | 19 (23.2 %) | |
Just water | 2 (4.9 %) | 6 (7.3 %) | |
None of these | 3 (7.3 %) | 19 (23.2 %) | |
Pacifier/dummy | |||
Latex | 5 (12.2 %) | 8 (9.8 %) | 0.202 |
Silicon | 21 (51.2 %) | 32 (39.0 %) | |
Attendance at day care or a nursery | 13 (31.7 %) | 19 (23.2 %) | 0.246 |
Mean age when started day care or a nursery, months | 7.3 (2.19) | 8.74 (3.74) | 0.269 |
Health | |||
Upper respiratory infection | |||
None | 9 (23.7 %) | 21 (27.6 %) | 0.856 |
Occasionally | 20 (52.6 %) | 36 (47.4 %) | |
Often | 9 (23.7 %) | 19 (25.0 %) | |
Lower respiratory infection | |||
None | 34 (89.5 %) | 71 (93.4 %) | 0.462 |
Occasionally | 4 (10.5 %) | 4 (5.3 %) | |
Often | 0 (0.0 %) | 1 (1.3 %) | |
Wheeze with upper respiratory infection | |||
None | 24 (63.2 %) | 59 (77.6 %) | 0.195 |
Occasionally | 11 (28.9 %) | 15 (19.7 %) | |
Often | 3 (7.9 %) | 2 (2.6 %) | |
Bronchiolitis (bronchitis) | |||
None | 36 (94.7 %) | 75 (98.7 %) | 0.106 |
Occasionally | 2 (5.3 %) | 1 (1.3 %) | |
Often | 0 (0.0 %) | 0 (0.0 %) | |
Middle ear infection | |||
None | 32 (84.2 %) | 70 (92.1 %) | 0.165 |
Occasionally | 6 (15.8 %) | 6 (7.9 %) | |
Often | 0 (0.0 %) | 0 (0 %) | |
Gastrointestinal illness | |||
None | 30 (78.9 %) | 69 (90.8 %) | 0.125 |
Occasionally | 7 (18.4 %) | 7 (9.2 %) | |
Often | 1 (2.6 %) | 0 (0.0 %) | |
Medication | |||
Median number of antibiotics in last 12 months | 1 (0–2) | 0.5 (0–1) | 0.341 |
Mean age when first received antibiotics, months | 8.65 (7.04) | 8.44 (6.59) | 0.964 |
Received aspirin | 1 (2.6 %) | 0 (0.0 %) | 0.333 |
Received paracetamol | 38 (100.0 %) | 74 (97.4 %) | 0.442 |
Received anti-inflammatories (e.g. Ibuprofen, Nurofen) | 29 (76.3 %) | 51 (67.1 %) | 0.214 |
Received anti-reflux medication | 11 (28.9 %) | 10 (13.2 %) | 0.039 |
Received any vaccinations | 37 (97.4 %) | 73 (96.0 %) | 0.565 |
Received any skin creams, lotions or powders | 33 (86.8 %) | 55 (72.4 %) | 0.079 |
All infants will food hypersensitivity (n = 41) compared to control infants | ||||
---|---|---|---|---|
Univariate | Multivariable* | |||
Odds ratio (95 % CI) | p value | Odds ratio (95 % CI) | p value | |
Wheeze, (at initial assessment) | 2.120 (0.940–4.782) | 0.092 | 20.591 (1.465–289.341) | 0.025 |
Maternal atopy | 5.192 (1.683–16.017) | 0.002 | 87.479 (1.021–7498.366) | 0.049 |
Gestation, weeks | 0.756 (0.585–0.978) | 0.033 | 0.171 (0.045–0.642) | 0.009 |
Age at first solids, weeks | 0.920 (0.830–0.998) | 0.044 | 0.506 (0.282–0.908) | 0.022 |
Mean infant healthy eating dietary pattern score, arbitrary units | 0.365 (0.229–0.583) | 0.002 | 0.155 (0.028–0.868) | 0.034 |
IgE-mediated (n = 21) compared to control infants | Non-IgE-mediated (n = 20) compared to control infants | |||||||
---|---|---|---|---|---|---|---|---|
Univariate | Multivariable** | Univariate | Multivariable** | |||||
Odds ratio | p | Odds ratio | p | Odds ratio | p | Odds ratio | p | |
Eczema (at initial assessment) | 17.83* (2.89–∞) | <0.001 | 18.67**** (1.03–338.41) | 0.048 | ||||
Rhinitis (at initial assessment) | 3.94 (1.31–11.83) | 0.023 | 4.80**** (1.19–19.36) | 0.027 | 2.96 (0.92–9.52) | 0.087 | ||
Maternal atopy | 11.54 (1.47–90.35) | 0.003 | ||||||
Vitamin D supplement during pregnancy | 8.68*** (0.66–∞) | 0.097 | ||||||
Age at first egg from any source, months | 1.05 (1.00–1.11) | 0.026 | Not included in analysis as likely reverse causality | |||||
Dog in the home | 3.24 (1.00–10.48) | 0.076 | 4.37 (1.38–13.80) | 0.015 | 19.49 (1.17–325.93) | 0.039 | ||
Wheeze associated with upper respiratory tract | 2.84 (1.01–7.98) | 0.052 | ||||||
Healthy eating dietary pattern score, arbitrary units | 0.36 (0.20–0.66) | 0.001 | 0.32**** (0.16–0.66) | 0.012 | 0.34 (0.19–0.62) | <0.001 | 0.28 (0.09–0.87) | 0.028 |
Maternal age, years | 0.87 (0.78–0.99) | 0.037 | ||||||
Paternal age, years | 0.893 (0.803–0.992) | 0.035 | ||||||
Maternal food hypersensitivity | 2.790 (0.994–7.831) | 0.055 | ||||||
Other household smoking | 5.133 (1.32–19.95) | 0.023 | ||||||
Consumed probiotics whilst breastfeeding | 3.31 (1.13–9.75) | 0.084 | 45.41 (3.41–604.67) | 0.004 | ||||
Age at first solid, months | 0.84 (0.73–0.97) | 0.021 | 0.60 (0.40–0.89) | 0.011 | ||||
Milk overlap, months | 0.94 (0.88–1.00) | 0.037 | ||||||
Received anti-reflux medication | 3.312 (1.13–9.75) | 0.030 | Not included in analysis as likely reverse causality |