Table 9

Differentials in infant mortality rates (source: household survey)

Category
 Deaths
 Child-years
 Mortality rate per 1000 child-years
 RR
 95% CI*
 P*
Year (July–June)
 2001–2
 184
 2,218.8
 82.9
 1
0.72 (for trend P = 0.75)

2002–3
 183
 2,324.7
 78.7
 0.95
 0.8 – 1.2

2003–4
 227
 2,659.8
 85.3
 1.03
 0.8 – 1.3
Mother's age at delivery
 20–29
 261
 3,398.7
 76.8
 1
0.005

30–39
 124
 1,702.2
 72.8
 0.95
 0.8 – 1.2

40–49
 27
 364.5
 74.1
 0.96
 0.6 – 1.4

Under 20
 181
 1,718.8
 105.3
 1.37
 1.1 – 1.7
Mother's education
 One or more years
 399
 5,123.9
 77.9
 1
0.038

None
 194
 2,063.6
 94.0
 1.21
 1.0 – 1.4
Sex
 Girls
 287
 3,537.7
 81.1
 1
0.70

Boys
 307
 3,665.5
 83.8
 1.03
 0.9 – 1.2
Twins
 Singleton
 518
 6,980.1
 74.2
 1
<0.0001

Twin
 76
 223.2
 340.5
 4.59
 3.4 – 6.2
Age
 0–27 days
 337
 574.2
 586.9
 1
<0.0001

28–365 days
 257
 6,629.0
 38.8
 0.07
 0.06 – 0.08
Ethnic group of household head
 Makonde
 220
 3,075.8
 71.5
 1
0.01

Mwera
 246
 2,867.3
 85.8
 1.20
 1.0 – 1.4

Yao
 29
 318.7
 91.0
 1.27
 0.8 – 2.0

Other
 99
 926.2
 106.9
 1.49
 1.2 – 1.9
Gender of household head
 Male
 478
 5,695.9
 83.9
 1
0.48

Female
 116
 1,493.2
 77.7
 0.93
 0.7 – 1.1
SES quintile of household
 Poorest
 109
 1,291.1
 84.4
 1
0.90 (test for trend)

Very poor
 122
 1,577.9
 77.3
 0.92
 0.7 – 1.2

Poor
 102
 1,182.1
 86.3
 1.02
 0.8 – 1.4

Less poor
 129
 1,540.9
 83.7
 0.99
 0.8 – 1.3

Least poor
 120
 1,513.7
 79.3
 0.94
 0.7 – 1.2
Distance to nearest health facility
 <5 km
 363
 4,778.9
 76.0
 1
0.02

≥ 5 km
 196
 2,061.2
 95.1
 1.25
 1.0 – 1.5
Effect of child's age on the relationship between twinning and mortality:
Twins under 28 days (neonates)
 Singleton
 280
 556.6
 503.0
 1
<0.0001

Twin
 57
 17.6
 3,242.6
 6.45
 4.5 – 9.2
Twins over 28 days (1–11 m)
 Singleton
 238
 6,423.4
 37.1
 1
<0.0001

Twin
 19
 205.6
 92.4
 2.49
 1.5 – 4.0
Effect of child's age on the relationship between maternal education and mortality:
In neonates: Mother's education
 ≥ 1 year
 238
 407.4
 584.3
 1
0.93

None
 98
 165.9
 590.8
 1.01
 0.8 – 1.3
In 1–11 month olds: Mother's education
 ≥ 1 year
 161
 4,716.7
 34.1
 1
0.003

None
 96
 1,897.8
 50.6
 1.48
 1.1 – 1.9
Effect of distance from the health facility on the relationship between maternal education and mortality
In those living < 5 km from a health facility: mothers education
 ≥ 1 year
 239
 3,466.
 68.9
 1


None
 123
 1,305.3
 94.2
 1.4
 1.1 – 1.7
 0.005
In those living ≥ 5 km from a health facility: mothers education
 ≥ 1 year
 140
 1,421.5
 98.5
 1


None
 56
 637.9
 87.8
 0.9
 0.7 – 1.2
 0.47

* From Poisson regression, adjusted for clustering from survey design

Armstrong Schellenberg et al. BMC Public Health 2008 8:194   doi:10.1186/1471-2458-8-194