Table 2.

Characteristics of cases and controls and univariate associations between risk factors and non-medicinal poisoning

Characteristic	Cases (%), n = 503	Controls (%), n = 4873	Unadjusted odds ratio (95% CI)
Child characteristics
Sex of child
Female	240 (48)	2372 (49)	1.00
Male	263 (52)	2501 (51)	1.04 (0.86 to 1.25)
Age when poisoning occurred, months
0–12	67 (13)	1697 (35)	1.00
13–24	226 (45)	1116 (23)	5.40 (4.05 to 7.20)
25–36	159 (32)	875 (18)	4.86 (3.58 to 6.60)
≥37	51 (10)	1185 (24)	1.06 (0.73 to 1.56)
Birth order of child
1st	338 (68)	3607 (74)	1.00
2nd	130 (26)	1094 (22)	1.35 (1.08 to 1.68)
3rd or more	35 (7)	172 (4)	2.42 (1.62 to 3.63)
Maternal characteristics
Maternal age at birth of child, years
<20	44 (9)	249 (5)	1.00
20–29	293 (58)	2531 (52)	0.66 (0.47 to 0.93)
30–39	161 (32)	1987 (41)	0.46 (0.32 to 0.66)
≥40	5 (1)	106 (2)	0.26 (0.10 to 0.68)
Maternal diagnosis of depression
No	454 (90)	4538 (93)	1.00
Yes	49 (10)	335 (7)	1.46 (1.06 to 2.01)
Maternal smoking
Never smoked	201 (40)	2279 (47)	1.00
Ex-smoker	25 (5)	198 (4)	1.39 (0.90 to 2.17)
Current smoker	137 (27)	1065 (22)	1.45 (1.15 to 1.83)
Missing	140 (28)	1331 (27)	1.18 (0.91 to 1.52)
Maternal alcohol misuse
Never	497 (98.81)	4847 (99.47)	1.00
≤1 year before poisoning	2 (0.40)	3 (0.06)	6.07 (1.01 to 36.47)
>1 year before poisoning	4 (0.80)	23 (0.47)	1.68 (0.58 to 4.86)
Social characteristics
Townsend index quintile
1 (least deprived)	89 (18)	1057 (22)	1.00
2	73 (15)	895 (18)	1.00 (0.71 to 1.39)
3	102 (20)	928 (19)	1.40 (1.02 to 1.92)
4	108 (21)	920 (19)	1.53 (1.11 to 2.11)
5 (most deprived)	102 (20)	750 (15)	1.87 (1.33 to 2.62)
Missing	29 (6)	323 (7)	0.96 (0.49 to 1.90)
Single parenthood
Single adult	226 (45)	1964 (40)	1.00
Two adults	241 (48)	2531 (52)	0.82 (0.67 to 1.00)
Other	36 (7)	378 (8)	0.83 (0.56 to 1.21)