Table 3

Risks of being born in categories of birth weight in all births 1986–2012 (ONS data) and all, term and preterm births 2006–2012 (NN4B data)*

	Unadjusted yearly OR (95% CI)	Adjusted† yearly OR (95% CI)	Unadjusted† yearly OR (95% CI) for whole study period	Adjusted† yearly OR (95% CI) for whole study period‡
ONS births 1986–2012
Female
VLBW	1.00	1.00	1.00	0.99
LBW	1.00	1.00	1.00	0.96
HBW	1.01	1.01	1.12	1.10
Male
VLBW	1.00	1.00	1.00	0.98
LBW	1.00	1.00	1.00	0.96
HBW	1.01	1.01	1.12	1.08
NN4B 2006–2012
Female, all live, singleton births
VLBW	0.97	0.96	0.91	0.88 (0.86 to 0.91)
LBW	0.98	0.98	0.94	0.94
HBW	1.01	1.01	1.03	1.02
Term (≥37 weeks’ gestation), n=2 172 435
VLBW	0.97 (0.93 to 1.02)	0.96 (0.92 to 1.01)	0.91 (0.80 to 1.06)	0.88 [0.78 to 1.03]
LBW	0.98	0.98	0.94	0.94
HBW	1.00	1.01	1.00	1.03
Preterm (<37 weeks’ gestation), n=120 665
VLBW	0.98	0.98	0.94 (0.91 to 0.97)	0.94 (0.91 to 0.97)
LBW	0.98	0.99	0.94	0.97
HBW	1.03 (0.99 to 1.07)	1.03 (0.99 to 1.06)	1.09 (0.97 to 1.23)	1.09 (0.97 to 1.19)
Male, all live, singleton births
VLBW	0.97	0.97	0.91	0.91
LBW	0.98	0.98	0.94	0.94
HBW	1.01	1.01	1.03	1.03
Male term (≥37 weeks’ gestation) n=2 270 840
VLBW	0.97 (0.93 to 1.02)	0.97 (0.92 to 1.02)	0.8 (0.8 to 1.06)	0.91 (0.78 to 1.06)
LBW	0.98	0.98	0.94	0.94
HBW	1.01	1.01	1	1.03
Male preterm (<37 weeks’ gestation), n=144 829
VLBW	0.98	0.98	0.94 (0.91 to 0.97)	0.94
LBW	0.98	0.99	0.94	0.97
HBW	1.00 (0.97 to 1.03)	1.00 (0.98 to 1.03)	1.00 (0.91 to 1.09)	1.00 (0.94 to 1.09)

*OR CIs not presented when these were ≤0.03 g or less wide; significant results in bold.
†Adjusted for maternal age, marital status, area-level deprivation, area-level ethnicity (ONS) and individual ethnicity (NN4B).
‡Birth weight change/OR pooled for whole study period ONS (1986–2012), NN4B (2006–2012).
HBW, high birth weight; LBW, low birth weight; NN4B, NHS Numbers for Babies; ONS, Office for National Statistics; VLBW, very low birth weight.