Table 5 Hazard ratio (HR) estimate independent variables using AG, PWP-TT, PWP-GT, Frailty Model

HR (95% CI)

HR (95% CI)

HR (95% CI)

HR (95% CI)

Age of mothers at first birth

  < 20 (ref.)

1.000

1.000

1.000

1.000

  20–34

0.713 (0.614,0.828)

1.052(0.933,1.188)

0.852(0.733,0.992)

0.730(0.620,0.828)

  35–49

0.050 (0.006,0.090)

0.384(0.053,2.794)

0.189(0.00,9.024)

0.725(0.626,0.849)

Mother’s current marital status

  Married(ref.)

1.000

1.000

1.000

1.000

  Widowed

1.140(0.834,1.540)

1.059(0.822,1.363)

0.911(0.658,1.263)

0.977(0.705,1.356)

  Divorced

1.440(0.720,2.860)

1.063(0.613,1.843)

1.243(0.692,2.234)

1.527(0.829,2.816)

Place of delivery

  Home(ref.)

1.000

1.000

1.000

1.000

  Health sector

0.886(0.768,0.997)

0.712(0.907, 1.165)

0.970(0.837,1.223)

0.935(0.805,1.087)

Residence

  Urban(ref.)

1.000

1.000

1.000

1.000

  Rural

1.020(0.836,1.230)

0.939(0.792,1.113)

0.885(0.706,0.995)

1.011(0.824,1.240)

Mother’s education level

  No education(ref.)

1.000

1.000

1.000

1.000

  Primary

1.210(1.010,1.460)

1.047(0.913,1.200)

1.049(0.885,1.245)

0.853(0.713,1.019)

  Secondary and above 

0.989(0.730,1.340)

0.960(0.769,1.204)

0.899(0.752, 1.076)

0.892(0.710,1.130)

Husband/partner’s education level

  Primary(ref.)

1.000

1.000

1.000

1.000

  Secondary and above

1.200(0.945, 1.520)

0.953(0.795,1.142)

0.977 (0.825, 1.157)

1.210(0.976,1.501)

Region

  Tigray(ref.)

1.000

1.000

1.000

1.000

  Afar

0.657 (0.438,0.987)

1.061(0.768,1.467)

0.960(0.640,1.442)

0.717(0.475,1.083)

  Amhara

0.768(0.541,1.090)

1.147(0.858,1.532)

0.998(0.692,1.437)

0.848(0.585,1.230)

  Oromia

0.736(0.543,0.997)

1.074(0.830,1.389)

0.985(0.720,1.348)

0.782(0.567,1.080)

  Somali

0.850(0.598,1.210)

1.091(0.776,1.534)

0.888(0.593,1.329)

0.814(0.542,1.222)

  Benishangul

0.833(0.614,1.130)

1.056(0.808,1.380)

0.957(0.694,1.320)

0.799(0.576,1.108)

  SNNPR

0.942(0.698,1.270)

1.145(0.882,1.488)

1.296(0.943,1.781)

0.982(0.713,1.353)

  Gambela

0.771(0.554,1.070)

0.995(0.759,1.304)

0.904(0.650,1.258)

0.753(0.537,1.055)

  Harari

0.775(0.554,1.090)

1.013(0.772,1.330)

1.050(0.750,1.469)

0.780(0.555,1.100)

  Addis Ababa

0.716(0.490,1.050)

1.055(0.802,1.386)

1.029(0.725,1.461)

0.749(0.521,1.076)

  Dire Dawa

0.820(0.567,1.190)

1.136(0.848,1.521)

1.066(0.739,1.538)

0.757(0.521,1.099)

Religion

  Orthodox(ref.)

1.000

1.000

1.000

1.000

  Protestant

1.230(0.971,1.560)

1.003(0.837,1.203)

1.078(0.857,1.358)

1.141(0.904,1.441)

  Muslim

1.260(1.010,1.580)

1.016(0.861,1.199)

1.056(0.855,1.305)

1.210(0.976,1.501)

  Catholic,traditional + 

1.03(0.586,1.810)

0.834(0.553,1.257)

0.864(0.528,1.413)

1.047(0.638,1.719)

Household size

  1–4 (small)(ref.)

1.000

1.000

1.000

1.000

  5–9 (medium)

3.110(2.49,3.880)

1.914(1.539,2.381)

1.804(1.455,2.237)

3.183(2.605,3.889)

  10 and more (Large)

2.660(1.870,3.770)

1.813(1.293,2.541)

1.880(1.352,2.613)

2.718(1.960,3.770)

Household wealth index

  Poorest(ref.)

1.000

1.000

1.000

1.000

  Poorer

0.957(0.778,1.180)

0.953(0.795,1.143)

0.838(0.682,1.030)

0.904(0.732,1.116)

  Middle

0.845(0.683,1.050)

0.827(0.688,0.994)

0.675(0.546,0.834)

0.776(0.625,0.965)

  Richer

0.950(0.751,1.200)

1.068(0.878,1.298)

0.859(0.683,1.081)

0.892(0.705,1.128)

  Richest

1.070(0.830,1.380)

0.962(0.767,1.205)

0.941(0.730,1.212)

1.067(0.822,1.385)

Sex of child

  Male(ref.)

1.000

1.000

1.000

1.000

  Female

0.853(0.776,0.938)

0.836(0.755,0.926)

0.835(0.739,0.944)

0.911(0.805,1.031)

Child is alive

  Yes(ref.)

1.000

1.000

1.000

1.000

  No

0.783(0.631,0.971)

0.705(0.533,0.934)

0.673(0.514,0.881)

0.681(0.522,0.889)

  Frailty Variance

0.148