Table 2 Perinatal factors for gout cases compared to matched population controls, with univariate odds ratios, ^a Only available from 1982, when recording of maternal smoking was initiated. OR odds ratio, n.s. non-significant, CI confidence interval

Maternal age groups

<20

75 (5%)

305 (6%)

Ref

20–35

1234 (88%)

4800 (87%)

1.05 (0.81–1.4)

0.7

36–

90 (6%)

410 (7%)

0.9 (0.64–1.3)

0.6

Maternal stature

–154

9 (1%)

50 (1%)

Ref

155–164

117 (8%)

553 (10%)

1.18 (0.56–2.5)

0.7

165–174

209 (15%)

773 (14%)

1.5 (0.7–3.1)

0.27

175–

34 (2%)

129 (2%)

1.46 (0.66–3.3)

0.35

Missing

1030 (72%)

4027 (71%)

--

--

Marital status

Married

616 (44)

2466 (45)

Ref

Single mother

283 (20)

1071 (19)

1.06 (0.9–1.24)

0.5

Missing

500 (36)

1978 (36)

--

--

BMI classes, at start, n (%)

<20

58 (4%)

273 (5%)

Ref

20–25

206 (15%)

835 (15%)

1.16 (0.84–1.6)

0.36

26–30

38 (3%)

120 (2%)

1.49 (0.9–2.4)

0.09

>30

16 (1%)

38 (1%)

1.98 (1.04–3.8)

0.04

Missing

1081 (77%)

4249 (77%)

--

--

Parity

0

584 (42%)

2345 (43%)

Ref

≥1

815 (58%)

3170 (57%)

1.03 (0.92–1.16)

0.6

Disease of the mother, n (%)

Recurrent urinary tract infection

18 (1.3)

82 (1.5)

0.86 (0.52–1.4)

0.6

Chronic kidney disease

1 (0.07)

6 (0.11)

--

Diabetes

9 (0.64)

12 (0.22)

2.98 (1.25–7.1)

0.01

Epilepsy

2 (0.1)

4 (0.07)

--

Asthma/lung disease

6 (0.4)

12 (0.22)

1.98 (0.7–5.3)

0.2

Inflammatory bowel disease

2 (0.14)

2 (0.04)

--

SLE

0

0

--

Hypertension

1 (0.07)

5 (0.09)

--

Maternal smoking, at start of pregnancy^a

Yes

159 (11)

480 (9)

1.57 (1.25–1.96)

<.0001

No

264 (19)

1248 (23)

Ref

Missing

976 (70)

3787 (69)

Season of birth

Month 1–3

358 (26%)

1454 (26%)

Ref

Month 4–6

389 (28%)

1503 (27%)

1.05 (0.9–1.2)

n.s.

Month 7–9

344 (25%)

1351 (25%)

1.03 (0.88–1.2)

n.s.

Month 10–12

299 (21%)

1183 (21%)

1.03 (0.87–1.2)

n.s.

Missing

24 (0.4)

9 (0.6)

--

Mode of delivery, n (%)

Vaginal

1353 (97)

5370 (97)

Ref

Caesarean (acute and elective)

46 (3)

145 (3)

1.26 (0.9–1.76)

0.17

Birth weight grams, n (%)

<2500

73 (5)

200 (4)

Ref

2500–2999

185 (13)

595 (11)

0.85 (0.62–1.17)

0.32

3000–3499

443 (32)

1693 (31)

0.72 (0.54–0.96)

0.02

3500–3999

456 (33)

1950 (35)

0.64 (0.48–0.85)

0.002

4000–4499

197 (14)

874 (16)

0.62 (0.45–0.84)

0.002

≥4500

45 (3)

203 (4)

0.61 (0.4–0.92)

0.02

Birth weight for gestational age, n (%)

Small for gestational age

82 (6)

187 (3)

1.77 (1.36–2.3)

<.0001

Normal for gestational age

1275 (91)

5153 (93)

Ref

Large for gestational age

42 (3)

175 (3)

0.97 (0.69–1.37)

0.86

Gestational age, days, n (%)

≤258

90 (6)

316 (6)

Ref

259–293

1168 (83)

4600 (83)

0.89 (0.7–1.1)

0.3

≥294

141 (10)

599 (11)

0.83 (0.6–1.17)

0.2

Number of older siblings, n (%)

0

582 (42)

2323 (42)

Ref

1

512 (37)

2038 (37)

1.003 (0.88–1.15)

n.s.

2

219 (16)

813 (15)

1.08 (0.9–1.28)

n.s.

≥3

86 (6)

341 (6)

1.007 (0.78–1.3)

n.s.

Congenital malformation, n (%)

Yes

92 (7)

275 (5)

1.34 (1.05–1.7)

0.018

No

1307 (93)

5240 (95)

Ref

Five most common malformations, n (%)

Urogenital malformation

27 (2)

11 (2)

0.97 (0.63–1.48)

0.88

Musculoskeletal malformation

12 (1)

40 (1)

1.18 (0.62–2.26)

0.61

Down’s syndrome

13 (1)

4 (0.1)

12.9 (4.2–39.7)

<.0001

Cardiovascular malformations

12 (0.8)

27 (0.5)

1.61 (0.8–3.3)

0.2

Face and throat malformations

6 (0.4)

17 (0.3)

1.39 (0.55–3.54)

0.5