Table 1.
Characteristics of DCHS study population
| Overall (n=1137 mothers; n=1143 infants)* | No LRTI†(n=688 mothers; n=690 infants) | LRTI‡(n=453 infants; 851 episodes)§ | Hospitalised LRTI‡(n=130 infants; 169 episodes) | ||
|---|---|---|---|---|---|
| Maternal characteristics (n=1137) | |||||
| Age (years) | 26 (22–31) | 25 (22–30) | 26 (22–31) | 26 (21–31) | |
| Currently married or cohabiting | 458/1137 (40%) | 277/688 (40%) | 181/449 (40%) | 43/129 (33%) | |
| Self-reported smoking antenatal | 306/1134 (27%) | 170/685 (25%) | 136/449 (30%) | 40/129 (31%) | |
| Self-reported smoking postnatal | 323/1061 (30%) | 180/622 (29%) | 143/439 (33%) | 43/125 (34%) | |
| HIV infection | 244/1134 (22%) | 127/686 (19%) | 117/448 (26%) | 33/129 (26%) | |
| History of asthma or atopy | 25/1130 (2%) | 14/686 (2%) | 11/444 (2%) | 4/128 (3%) | |
| Family history of asthma or atopy | 53/987 (5%) | 28/555 (5%) | 25/432 (6%) | 9/120 (8%) | |
| Infant characteristics (n=1143) | |||||
| Lives in formal home or flat | 617/1143 (54%) | 378/688 (55%) | 239/453 (53%) | 69/130 (53%) | |
| At least one parent employed | 579/1143 (51%) | 357/688 (52%) | 222/453 (49%) | 53/130 (41%) | |
| Electricity in the home | 1071/1139 (94%) | 650/689 (94%) | 421/450 (94%) | 123/128 (96%) | |
| Plumbing in the home | 973/1140 (85%) | 602/689 (87%) | 371/451 (82%) | 112/129 (87%) | |
| Household income per month | |||||
| <R1000 (US$67) | 407/1114 (37%) | 245/674 (36%) | 162/440 (37%) | 51/127 (40%) | |
| R1000–5000 (US$67–333) | 553/1114 (50%) | 331/674 (49%) | 222/440 (50%) | 56/127 (44%) | |
| R5000–10 000 (US$333–667) | 128/1114 (11%) | 81/674 (12%) | 47/440 (11%) | 16/127 (13%) | |
| >R10 000 (US$667) | 26/1114 (2%) | 17/674 (3%) | 9/440 (2%) | 4/127 (3%) | |
| Crowding: individuals per house | 4 (3–6) | 4 (3–6) | 4 (3–6) | 5 (3–6) | |
| Gestational age (weeks) | 39 (38–40) | 39 (38–40) | 39 (37–40) | 39 (37–40) | |
| Premature (<37 weeks gestation) | 194/1143 (17%) | 111/688 (16%) | 83/453 (18%) | 32/130 (25%) | |
| Gestational age (weeks) among premature births | 35 (32–36) | 35 (33–36) | 34 (32–36) | 34 (30–36) | |
| Birthweight (kg) | 3·08 (2·71–3·42) | 3·12 (2·76–3·44) | 3·02 (2·61–3·38) | 2·97 (2·58–3·32) | |
| HIV-infected | 2/1143 (<1%) | 1/690 (<1%) | 1/453 (<1%) | 1/130 (<1%) | |
| HIV-exposed uninfected | 246/1143 (22%) | 127/690 (18%) | 119/453 (26%) | 32/130 (25%) | |
| Initiated breastfeeding | 1046/1137 (92%) | 630/685 (92%) | 417 (92%) | 119/130 (92%) | |
| Exclusive breastfeeding at 6 weeks | 503/1068 (47%) | 305/627 (49%) | 198/441 (45%) | 53/130 (42%) | |
| Exclusive breastfeeding at 3 months | 279/1068 (26%) | 160/627 (26%) | 119/441 (27%) | 31/125 (25%) | |
| Vaccination coverage | |||||
| 6 weeks | 1039/1043 (>99%) | 602/604 (100%) | 437/439 (100%) | 123/125 (98%) | |
| 10 weeks | 1024/1029 (>99%) | 587/590 (99%) | 437/439 (100%) | 123/125 (98%) | |
| 14 weeks | 1013/1013 (100%) | 578/578 (100%) | 435/435 (100%) | 123/123 (100%) | |
| 9 months | 964/974 (99%) | 547/553 (99%) | 417/421 (99%) | 112/115 (97%) | |
| 18 months | 759/829 (92%) | 442/478 (92%) | 317/351 (90%) | 95/103 (92%) | |
| Age category at end of follow-up | |||||
| 0 to <1 year | 128/1143 (11%) | 115/688 (17%) | 13/453 (3%) | 7/130 (5%) | |
| 1 to <2 years | 21/1143 (2%) | 17/688 (2%) | 4/453 (1%) | 1/130 (1%) | |
| ≥2 years | 994/1143 (87%) | 558/688 (81%) | 436/453 (96%) | 122/130 (94%) | |
| Follow-up (years) | 2·05 (2·00–2·11) | 2·02 (2·00–2·10) | 2·06 (2·00–2·12) | 2·06 (2·00–2·11) | |
Data are n/N (%); or median (IQR). LRTI=lower respiratory tract infection. DCHS=Drakenstein Child Health Study.
*
Four sets of twins, one set of triplets.
†
Includes 12 observations that ended before 14 days.
‡
Excludes congenital cases.
§
Includes the number of children ever developing LRTI in the first 2 years; however, some children had both RSV and non-RSV LRTI events.