Table 3 The incidence rate ratios of CEB and explanatory variables among women of reproductive age in Kenya 2003–2014

Age-group

 15–19

0.32*** (0.29–0.36)

0.35*** (0.32–0.40)

0.34*** (0.31–0.38)

 20–29

0.73*** (0.70–0.75)

0.77*** (0.75–0.80)

0.74*** (0.72–0.76)

 30–39

0.99 (0.96–1.02)

1.03 (0.99–1.06)

0.99 (0.97–1.01)

 40–49

Reference

Reference

Reference

Level of education

 None

Reference

Reference

Reference

 Primary

1.05 (0.99–1.10)

0.99 (0.95–1.05)

0.97 (0.94–1.03)

 Secondary

0.96 (0.91–1.02)

0.93 **(0.88–0.99)

0.88*** (0.85–0.92)

 Higher

0.93 (0.86–1.01)

0.84*** (0.78–0.91)

0.78*** (0.74–0.82)

Place of residence

 Urban

0.96 (0.91-1.00)

0.96*** (0.91–1.01)

0.96*** (0.94–0.98)

 Rural

Reference

Reference

Reference

Age at first sexual intercourse

 Below 15

Reference

Reference

Reference

 15–19

0.94** (0.91–0.98)

0.89*** (0.86–0.92)

0.93** (0.91–0.95)

 20+

0.84*** (0.79–0.88)

0.77*** (0.73–0.81)

0.80*** (0.78–0.83)

Age at first marriage

 Below 18

Reference

Reference

Reference

 18–24

0.87*** (0.84–0.89)

0.86*** (0.83–0.86)

0.86*** (0.85–0.88)

 25+

0.71*** (0.66–0.76)

0.69*** (0.65–0.74)

0.68*** (0.65–0.71)

Family size preferences

 0–2

Reference

Reference

Reference

 3–4

1.10*** (1.06–1.14)

1.10*** (1.06–1.14)

1.07*** (1.04–1.10)

 5+

1.19*** (1.14–1.24)

1.25*** (1.20–1.30)

1.20*** (1.16–1.24)

Child mortality experience

 No child death

Reference

Reference

Reference

 One or more deaths

1.33*** (1.29–1.37)

1.25*** (1.21–1.29)

1.28*** (1.25–1.31)

Wealth Index

 Lowest

Reference

Reference

Reference

 Second

0.95*** (0.91–0.98)

0.99 (0.95–1.03)

0.97*** (0.94–0.99)

 Middle

0.94** (0.90–0.98)

0.91*** (0.87–0.95)

0.92** (0.89–0.95)

 Fourth

0.87** (0.83–0.91)

0.86*** (0.82–0.90)

0.83*** (0.81–0.86)

 Highest

0.79*** (0.74–0.84)

0.76*** (0.71–0.81)

0.77*** (0.74–0.80)

Regions

 Nairobi

Reference

Reference

Reference

 Central

1.02 (0.95–1.09)

0.96 (0.89–1.04)

0.90** (0.84–0.97)

 Coast

1.01 (0.93–1.09)

1.06 (0.99–1.13)

0.97 (0.90–1.05)

 Eastern

1.08** (1.04–1.16)

1.04 (0.97–1.12)

0.99 (0.91–1.06)

 Nyanza

1.10*** (1.03–1.18)

1.07 (0.99–1.16)

1.06 (0.98–1.15)

 Rift valley

1.18*** (1.10–1.27)

1.16*** (1.09–1.25)

1.09** (1.01–1.17)

 Western

1.14*** (1.07–1.23)

1.10** (1.03–1.18)

1.11** (1.03–1.21)

 North Eastern

1.28*** (1.14–1.43)

1.21*** (1.10–1.34)

1.11** (1.02–1.22)

Religion

 Roman catholic

Reference

Reference

Reference

 Protestants/other Christian

1.01 (0.98–1.04)

0.99 (0.96–1.03)

0.99 (0.98–1.02)

 Muslim

1.03 (0.95–1.12)

0.95 (0.90–1.01)

1.07*** (1.02–1.12)

 No religion/other religions

0.99 (0.90–1.08)

0.96 (0.89–1.03)

1.01 (0.96–1.07)