Table 3

Associations between length of interbirth interval and mortality in 1980–2008 (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
MonthsModel 1Model 2Model 3Model 1Model 2Model 3
Interval 1st–2nd birth (parents with 2+ births)
 01.01 (0.97 to 1.12)1.05 (0.94 to 1.16)1.05 (0.95 to 1.16)1.11 (0.98 to 1.25)1.14* (1.01 to 1.29)1.15* (1.01 to 1.30)
 0>181.18** (1.14 to 1.22)1.17 **(1.13 to 1.21)1.17** (1.13 to 1.21)1.10**(1.06 to 1.15)1.12** (1.07 to 1.16)1.13** (1.08 to 1.17)
 18–291.04** (1.02 to 1.07)1.05** (1.02 to 1.08)1.05** (1.02 to 1.08)1.01 (0.97 to 1.04)1.02 (0.98 to 1.05)1.02 (0.99 to 1.06)
 30–41111111
 42–591.01 (0.98 to 1.04)0.99 (0.96 to 1.02)0.99 (0.96 to 1.02)1.00 (0.96 to 1.03)0.98 (0.94 to 1.02)0.97 (0.94 to 1.01)
 60–891.06** (1.02 to 1.09)1.03 (0.99 to 1.02)1.01 (0.97 to 1.00)1.08** (1.03 to 1.12)1.05* (1.00 to 1.09)1.01 (0.97 to 1.06)
 90+1.11** (1.06 to 1.15)1.06* (1.01 to 1.10)0.96 (0.92 to 1.01)1.11** (1.05 to 1.16)1.05 (1.00 to 1.11)0.95 (0.90 to 1.00)
Interval 2nd–3rd birth (parents with 3+ births)
 01.06 (0.96 to 1.17)1.09 (0.98 to 1.21)1.09 (0.99 to 1.21)1.14* (1.01 to 1.29)1.17** (1.04 to 1.32)1.18**(1.05 to 1.33)
 0>181.15** (1.09 to 1.21)1.13** (1.07 to 1.19)1.13 **(1.07 to 1.19)1.06 (0.99 to 1.13)1.05 (0.98 to 1.13)1.06 (0.99 to 1.13)
 18–291.10** (1.05 to 1.15)1.09** (1.04 to 1.14)1.09** (1.04 to 1.14)1.01 (0.96 to 1.07)1.01 (0.96 to 1.07)1.01 (0.96 to 1.07)
 30–41111111
 42–591.02 (0.97 to 1.07)1.02 (0.97 to 1.06)1.01 (0.97 to 1.06)0.95* (0.90 to 1.00)0.94* (0.89 to 1.00)0.94* (0.89 to 0.99)
 60–890.98 (0.93 to 1.02)0.97 (0.93 to 1.02)0.96* (0.92 to 1.01)0.97 (0.92 to 1.03)0.96 (0.91 to 1.00)0.95* (0.89 to 1.00)
 90+0.99 (0.95 to 1.04)0.97 (0.92 to 1.02)0.91** (0.86 to 0.98)0.92** (0.86 to 0.98)0.89** (0.84 to 0.95)0.83** (0.77 to 0.88)
Interval 3rd–4th birth (parents with 4 births)
 00.95 (0.81 to 1.10)0.97 (0.83 to 1.13)0.97 (0.84 to 1.14)0.98 (0.81 to 1.18)1.00 (0.83 to 1.20)1.00 (0.89 to 1.21)
 0>181.10 (0.99 to 1.22)1.09 (0.98 to 1.21)1.09 (0.97 to 1.21)1.07 (0.94 to 1.22)1.06 (0.93 to 1.21)1.07 (0.93 to 1.22)
 18–291.08 (0.99 to 1.18)1.08 (0.99 to 1.18)1.08 (1.00 to 1.18)1.14* (1.02 to 1.26)1.14* (1.02 to 1.26)1.14** (1.02 to 1.27)
 30–41111111
 42–591.01 (0.93 to 1.10)1.01 (0.93 to 1.10)1.01 (0.92 to 1.10)0.99 (0.89 to 1.11)0.99 (0.89 to 1.10)0.99 (0.88 to 1.07)
 60–890.95 (0.87 to 1.04)0.95 (0.87 to 1.04)0.94 (0.86 to 1.03)0.98 (0.88 to 1.09)0.97 (0.87 to 1.08)0.95 (0.86 to 1.07)
 90+0.93 (0.85 to 1.02)0.91* (0.83 to 1.00)0.87** (0.79 to 0.96)0.98 (0.88 to 1.10)0.96 (0.86 to 1.08)0.92 (0.82 to 1.04)
  • Model 1: age; period; years of education; marital status. Model 2: + age at first birth; parity. Model 3: + change in coparent. Numbers of deaths and person years of exposure shown in table 2 and online supplementary table S1.

  • *p<0.05; **p<0.01.