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.
| Men | Women | |||||
|---|---|---|---|---|---|---|
| Months | Model 1 | Model 2 | Model 3 | Model 1 | Model 2 | Model 3 |
| Interval 1st–2nd birth (parents with 2+ births) | ||||||
| 0 | 1.01 (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>18 | 1.18** (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) |
| 18–29 | 1.04** (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) |
| 30–41 | 1 | 1 | 1 | 1 | 1 | 1 |
| 42–59 | 1.01 (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) |
| 60–89 | 1.06** (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) | ||||||
| 0 | 1.06 (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>18 | 1.15** (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) |
| 18–29 | 1.10** (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) |
| 30–41 | 1 | 1 | 1 | 1 | 1 | 1 |
| 42–59 | 1.02 (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) |
| 60–89 | 0.98 (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) | ||||||
| 0 | 0.95 (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>18 | 1.10 (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) |
| 18–29 | 1.08 (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) |
| 30–41 | 1 | 1 | 1 | 1 | 1 | 1 |
| 42–59 | 1.01 (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) |
| 60–89 | 0.95 (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.