Table 3. Associations between birth weight and infant mortality, illness, absence of care seeking and health-facility admission in the neonatal period and early and late infancy, 2010–2011.
| Variable, time perioda | Value for infants with birth weight of: |
|||
|---|---|---|---|---|
| ≥ 2.5 kg | 2.00–2.49 kg | 1.50–1.99 kg | < 1.50 kg | |
| Mortality, neonatal period | ||||
| No. of deaths (no. of PDOFU) | 144 (51 8 319) | 53 (80 502) | 45 (11 146) | 35 (2 502) |
| Deaths/1000 YOFU | 97.9 (83.1–115.2) | 231.9 (177.2–303.6) | 1357.1 (1 006.5–1 829.9) | 4947.3 (3 552.1–6 890.4) |
| Adjusted hazard ratio (95% CI)b | Ref | 2.29 (1.66–3.15) | 14.71 (10.37–20.86) | 48.45 (32.81–71.55) |
| Mortality, early infancy | ||||
| No. of deaths (no. of PDOFU) | 157 (2 884 213) | 61 (442 344) | 22 (57 927) | 8 (11 717) |
| Deaths/1000 YOFU | 19.1 (16.3–22.4) | 47.1 (36.3–61.0) | 151.2 (101.4–225.6) | 249.6 (124.8–499.1) |
| Adjusted hazard ratio (95% CI)b | Ref | 2.45 (1.81–3.31) | 7.22 (4.57–11.42) | 12.95 (6.30–26.60) |
| Mortality, late infancy | ||||
| No. of deaths (no. of PDOFU) | 132 (3 450 857) | 33 (522 731) | 4 (67 449) | 4 (12 897) |
| Deaths/1000 YOFU | 14.1 (11.8–16.7) | 23.2 (16.5–32.6) | 21.8 (8.2–58.0) | 113.9 (42.8–303.6) |
| Adjusted hazard ratio (95% CI)b | Ref | 1.60 (1.09–2.35) | 1.61 (0.59–4.39) | 8.42 (3.09–22.92) |
| Illness, neonatal period | ||||
| No. of episodes (no. of PDOFU) | 2 343 (537 087) | 411 (83 316) | 106 (11 533) | 42 (2 534) |
| Episodes/1000 YOFU | 1 593.4 (1 530.2–1 659.2) | 1 801.8 (1 635.8–1 984.7) | 3 357.0 (2 775.1–4 061.0) | 6 053.9 (4 473.9–8 191.7) |
| Adjusted relative risk (95% CI)b | Ref | 1.00 (0.89–1.12) | 1.57 (1.27–1.95) | 1.58 (1.13–2.21) |
| Illness, early infancy | ||||
| No. of episodes (no. of PDOFU) | 14 644 (2 882 964) | 2246 (441 850) | 324 (57 927) | 67 (11 543) |
| Episodes/1000 YOFU | 1 855.3 (1 825.5–1 885.6) | 1 856.6 (1 781.4–1 935.0) | 2 042.9 (1 832.2–2 277.9) | 2 120.1 (1 668.7–2 693.7) |
| Adjusted relative risk (95% CI)b | Ref | 0.99 (0.94–1.04) | 1.10 (0.97–1.23) | 1.10 (0.85–1.43) |
| Illness, late infancy | ||||
| No. of episodes (no. of PDOFU) | 30 776 (341 2047) | 4 689 (516 711) | 596 (66 629) | 122 (12 561) |
| Episodes/1000 YOFU (95% CI) | 3 294.5 (3 257.9–3331.5) | 3 314.5 (3 221.0–3 410.8) | 3 267.2 (3 015.1–3 540.3) | 3 547.5 (2 970.7–4 236.3) |
| Adjusted relative risk (95% CI)b | Ref | 0.99 (0.96–1.03) | 0.99 (0.89–1.08) | 1.07 (0.87–1.32) |
| Absence of care seeking, neonatal period | ||||
| No. of absences (no. of illness episodes) | 1 210 (2 378) | 217 (420) | 78 (107) | 30 (44) |
| Percentage of illness episodes without care seeking (95% CI) | 50.9 (48.9–52.9) | 51.7 (46.9–56.4) | 72.9 (63.7–80.5) | 68.2 (53.0–80.3) |
| Adjusted odds ratio (95% CI)b | Ref | 1.04 (0.81–1.34) | 3.30 (1.98–5.48) | 2.07 (0.97–4.43) |
| Absence of care seeking, early infancy | ||||
| No. of absences (no. of illness episodes) | 2 549 (15 227) | 403 (2 331) | 82 (333) | 8 (70) |
| Percentage of illness episodes without care seeking (95% CI) | 16.7 (16.2–17.3) | 17.3 (15.8–18.9) | 24.6 (20.3–29.5) | 11.4 (5.8–21.3) |
| Adjusted odds ratio (95% CI)b | Ref | 1.03 (0.90–1.19) | 1.74 (1.26–2.39) | 0.63 (0.27–1.46) |
| Absence of care seeking, late infancy | ||||
| No. of absences (no. of illness episodes) | 3 921 (30 510) | 594 (4 654) | 75 (591) | 14 (122) |
| Percentage of illness episodes without care seeking (95% CI) | 12.9 (12.5–13.2) | 12.8 (11.8–13.8) | 12.7 (10.2–15.6) | 11.5 (6.9–18.5) |
| Adjusted odds ratio (95% CI)b | Ref | 0.97 (0.86–1.09) | 0.98 (0.72–1.32) | 0.85 (0.43–1.66) |
| Health-facility admission, neonatal period | ||||
| No. of admissions (no. of illness episodes) | 250 (2 378) | 48 (420) | 7 (107) | 6 (44) |
| Percentage of illness episodes with admission (95% CI) | 10.5 (9.3–11.8) | 11.4 (8.7–14.8) | 6.5 (3.1–13.1) | 13.6 (6.2–27.4) |
| Adjusted odds ratio (95% CI)b | Ref | 1.11 (0.77–1.60) | 0.56 (0.24–1.29) | 1.59 (0.59–4.27) |
| Health-facility admission, early infancy | ||||
| No. of admissions (no. of illness episodes) | 1 019 (15 227) | 194 (2 331) | 28 (333) | 6 (70) |
| Percentage of illness episodes with admission (95% CI) | 6.7 (6.3–7.1) | 8.3 (7.3–9.5) | 8.4 (5.9–11.9) | 8.6 (3.9–17.9) |
| Adjusted odds ratio (95% CI)b | Ref | 1.35 (1.12–1.63) | 1.19 (0.75–1.89) | 1.34 (0.51–3.52) |
| Health-facility admission, late infancy | ||||
| No. of admissions (no. of illness episodes) | 2 227 (30 510) | 338 (4 654) | 53 (591) | 11 (122) |
| Percentage of illness episodes with admission (95% CI) | 7.3 (7.0–7.6) | 7.3 (6.6–8.0) | 9.0 (6.9–11.6) | 9.0 (5.1–15.6) |
| Adjusted odds ratio (95% CI)b | Ref | 1.03 (0.89–1.18) | 1.24 (0.88–1.75) | 1.36 (0.65–2.85) |
CI: confidence interval; PDOFU: person-days of follow-up; Ref: reference; YOFU: years of follow-up.
a The neonatal period, early infancy and late infancy were represented by ages of 0–364, 0–27, 28–182 and 183–364 days, respectively.
b Adjusted a priori for infant sex and single/multiple birth, maternal age, education, illness and occupation and household exposure to indoor smoke, distance to nearest health facility, ethnicity, number of children, religion and socioeconomic status.