Table 4

Associations between length of interbirth interval and mortality in 1980–2008 by parity (ORs and 95% CIs from discrete-time hazards models), men and women born during 1935–1968 and aged 40–73 years with two to four children

MenWomen
MonthsParity 2Parity 3Parity 4Parity 2Parity 3Parity 4
Interval 1st–2nd birth
 01.07 (0.92 to 1.25)1.14 (0.97 to 1.34)0.78 (0.59 to 1.04)1.36** (1.15 to 1.61)1.00 (0.81 to 1.24)0.90 (0.64 to 1.27)
 0>181.19** (1.12 to 1.25)1.17 **(1.11 to 1.23)1.11** (1.03 to 1.20)1.16** (1.08 to 1.24)1.12**(1.05 to 1.19)1.10* (1.00 to 1.21)
Interval 2nd–3rd birth†
 01.07 (0.95 to 1.20)1.18 (0.97 to 1.44)1.26**(1.10 to 1.44)0.97 (0.74 to 1.26)
 0>181.14** (1.06 to 1.22)1.12* (1.02 to 1.22)1.10* (1.00 to 1.20)1.00 (0.90 to 1.11)
Number of intervals <18 months
 0111111
 11.17** (1.11 to 1.22)1.12** (1.08 to 1.16)1.09**(1.03 to 1.15)1.18**(1.12 to 1.26)1.21**(1.12 to 1.30)1.06 (0.99 to 1.14)
 21.41**(1.26 to 1.58)1.18**(1.08 to 1.30)1.25**(1.16 to 1.35)1.06 (0.94 to 1.19)
 31.18 (0.88 to 1.57)1.17 (0.79 to 1.72)
Average interval length
 0–171.22* (1.12 to 1.32)1.19* (1.04 to 1.36)1.12**(1.01 to 1.24)1.22**(1.02 to 1.44)
 18–291.07* (1.02 to 1.12)1.10**(1.02 to 1.18)1.06* (1.00 to 1.13)1.01 (0.92 to 1.10)
 30–411111
 42–590.94* (0.90 to 0.98)0.94 (0.88 to 1.01)0.94* (0.89 to 1.00)1.00 (0.92 to 1.08)
 60–890.94* (0.89 to 0.98)0.89* (0.82 to 0.98)0.91**(0.86 to 0.97)0.87* (0.78 to 0.98)
 90+0.76**(0.70 to 0.82)0.74**(0.64 to 0.87)0.85**(0.76 to 0.94)0.44**(0.25 to 0.77)
Deaths22 11215 093608214 73610 0153981
Person years5692.93676.71210.05872.13879.11308.8
  • Models include age; period; years of education; marital status, age at first birth and change in coparent since preceding birth.

  • *p<0.05; **p<0.01.

  • Reference category is 30–41 months.