Table 2

Unadjusted and adjusted odds ratios and PAR % of risk factors for perinatal mortality (22.0 weeks–6 days) of singletons in 2000–2006

Risk factor	Prevalence risk factor,%	Absolute mortalitymean/year	Unadjusted perinatal mortality	Adjusted* perinatal mortality	Adjusted† perinatal mortality	PAR%
Risk factor	Prevalence risk factor,%	n	Odds ratio (95% CI)	Odds ratio (95% CI)	Odds ratio (95% CI)	PAR%
Year effect	100.0	1759	0.97 (0.96 to 0.98)		0.97 (0.96 to 0.98)	NA
Maternal age (years)
<20	1.8	50	1.80 (1.62 to 2.00)	1.58 (1.41 to 1.76)	1.57 (1.41 to 1.75)	1.4
20–24	10.2	214	1.32 (1.25 to 1.40)	1.22 (1.15 to 1.29)	1.22 (1.15 to 1.29)	3.1
25–34	68.6	1096	1.00	1.00	1.00
35–39	17.0	332	1.22 (1.17 to 1.28)	1.20 (1.14 to 1.26)	1.21 (1.15 to 1.27)	3.6
⩾40	2.5	68	1.75 (1.59 to 1.92)	1.51 (1.38 to 1.67)	1.53 (1.39 to 1.68)	1.8
Parity
0 Nulliparous	46.3	895	1.38 (1.32 to 1.44)	1.31 (1.25 to 1.37)	1.31 (1.25 to 1.36)	14.8
1	35.8	504	1.00	1.00	1.00
2–3	16.0	294	1.31 (1.24 to 1.38)	1.24 (1.18 to 1.31)	1.24 (1.18 to 1.31)	4.6
4+	2.5	66	2.42 (2.20 to 2.67)	1.98 (1.79 to 2.19)	1.97 (1.78 to 2.18)	2.7
Non-western ethnicity	16.2	382	1.45 (1.38 to 1.51)	1.39 (1.33 to 1.46)	1.40 (1.33 to 1.47)	6.6
Level of urbanisation
Very urban	19.5	374	1.12 (1.07 to 1.17)	0.99 (0.94 to 1.03)	0.99 (0.94 to 1.03)	2.3
Medium urban/rural	62.6	1074	1.00	1.00	1.00
Very rural	17.9	311	1.01 (0.97 to 1.06)	1.05 (1.00 to 1.10)	1.05 (1.00 to 1.10)	0.2
Assisted conception	1.7	53	1.79 (1.62 to 1.99)	1.71 (1.54 to 1.90)	1.71 (1.54 to 1.90)	1.3
Maternal medical condition	9.5	255	1.63 (1.55 to 1.71)	1.59 (1.51 to 1.67)	1.59 (1.52 to 1.68)	5.7
Male gender child	51.4	935	1.07 (1.04 to 1.11)	1.07 (1.04 to 1.11)	1.07 (1.04 to 1.11)	3.6

*Adjusted for maternal age, parity, ethnicity, urbanisation, assisted conception, medical condition and male gender.
†Adjusted for maternal age, parity, ethnicity, urbanisation, assisted conception, medical condition, male gender and year.
PAR, population-attributable risk.
NA, not applicable.