Characteristics of cases and community controls (percentage, unless stated otherwise)
| Characteristics | Cases n=567 | Community controls n=2320 |
|---|---|---|
| Study centre | ||
| Nottingham | 193 (34.0) | 738 (31.8) |
| Bristol | 179 (31.6) | 794 (34.2) |
| Norwich | 106 (18.7) | 467 (20.1) |
| Newcastle | 89 (15.7) | 321 (13.8) |
| Median age in years (IQR)* | 2.18 (1.49, 2.92) | 2.24 (1.54, 3.02) |
| Age group: | ||
| 0–12 months | 65 (11.5) | 204 (8.8) |
| 13–36 months | 378 (66.7) | 1575 (67.9) |
| 37–62 months | 124 (21.9) | 541 (23.3) |
| Male | 280 (49.4) | 1210 (52.2) |
| Ethnic group: white | 514 (92.1) [9] | 2115 (92.6) [36] |
| Children aged 0–4 years in family | [11] | [29] |
| 0 | 6 (1.1) | 16 (0.7) |
| 1 | 299 (53.7) | 1379 (60.2) |
| 2 | 229 (41.2) | 810 (35.4) |
| ≥3 | 22 (4.0) | 86 (3.8) |
| First child | 210 (41.7) [64] | 895 (42.7) [222] |
| Maternal age ≤19 at birth of first child† | 84 (16.5) [8] | 208 (9.7) [14] |
| Single adult household | 92 (16.6) [13] | 262 (11.5) [43] |
| Median weekly hours out-of-home child care (IQR) | 12 (0.5, 22.0) [31] | 15 (2.5, 24.0) [112] |
| Adults in paid work | [11] | [35] |
| ≥2 | 263 (47.3) | 1281 (56.1) |
| 1 | 184 (33.1) | 742 (32.5) |
| 0 | 109 (19.6) | 262 (11.5) |
| Receives state benefits | 228 (41.7) [20] | 795 (35.1) [54] |
| Overcrowding (>1 person per room) | 46 (8.8) [42] | 163 (7.4) [128] |
| Non-owner occupier | 241 (43.5) [13] | 771 (33.8) [41] |
| Household has no car | 81 (14.6) [11] | 219 (9.6) [28] |
| Median IMD score (IQR) | 17.5 (10.3, 31.7) | 15.1 (9.3,26.5) [24] |
| Median distance (km) from hospital (IQR) | 3.5 (2.2, 5.9) | 4.0 (2.4, 7.6) [24] |
| Mean Child Behaviour Questionnaire (CBQ) score (SD) | 4.75 (0.91) [24] | 4.61 (0.86) [186] |
| Long-term health condition | 53 (9.4) [5] | 187 (8.1) [21] |
| Median Child Health Visual Analogue scale (IQR) | 9.8 (8.8, 10) [2] | 9.6 (8.4, 10) [14] |
| Median health-related quality of life (PedsQL) (IQR)‡ | n=326 [3] | n=1354 [24] |
| 91.7 (85.7, 97.2) | 89.3 (82.1, 95.2) | |
| Parental assessment of child's ability to access poisons§ | [21] | [96] |
| All scenarios ‘not likely’ | 22 (4.0) | 112 (5.0) |
| ≥1 scenario ‘quite likely’ and none ‘very likely’ | 100 (18.3) | 513 (23.1) |
| ≥1 scenario ‘very likely’ | 424 (77.7) | 1599 (71.9) |
| Median Parenting Daily Hassles (PDH) scale (IQR)¶ | 14.0 (10.3,18.0) [50] | 14.0 (11.0,18.0) [113] |
| Mean Hospital Anxiety and Depression scale (HADS) (SD)¶ | 10.9 (6.1) [15] | 10.8 (6.2) [25] |
[ ] missing values.
*For cases and community controls aged over 5 years, the case poisoning occurred prior to fifth birthday but study questionnaire was completed after fifth birthday.
†Asked only when mothers completed questionnaire. IMD: higher score reflects greater deprivation. CBQ: higher score reflects more active and intense behaviour. PDH: higher score reflects more hassle. HADS: higher score reflects greater symptoms of anxiety/depression. Child Health Visual Analogue Scale: range 0–10, higher score reflects better health. PedsQL: measured only in those aged ≥2 years, higher score reflects better quality of life.
‡Missing values are those with ≥50% items on any scale missing.
Ability to access poisons is measured by responses to the following questions. How likely do you think it is that your child could: (a) reach or climb onto a worktop; (b) reach or climb onto something to reach a cupboard at adult eye level; (c) open cupboards, drawers or medicine cabinets with locks or safety catches on them; (d) open a fridge with a lock or safety catch on it; (e) open a container with a child resistant cap; (f) open a lockable medicine box; (g) get medicines out of blister packs; (h) touch things that you have told him/her not to and (i) open a safety gate. Response options were very likely, quite likely, not likely, don't know. Responses were categorised as shown in the table.
¶Missing values are those with >1 item missing.
IMD, Index of Multiple Deprivation.