Table 4.

Results of multivariate modeling of risk factors associated with any LRTI (model A), KP-LRTI versus no LRTI (model B) or KP-LRTI among LRTI cases (model C)

	Model A:All LRTI vs all controls		Model B: KP-LRTI vs no LRTI	Model C: KP-LRTI vs non-KP-LRTI
	Unadjusted OR(95% CI)	Adjusted* OR(95% CI)	Adjusted* OR(95% CI)	Adjusted* OR(95% CI)
Child characteristics
Sex: Male (ref. female)	1.53 (1.10–2.12)	1.47 (1.04–2.07)	1.55 (0.77–3.10)	1.56 (0.79–3.07)
Preterm (<37 weeks gestation)	1.96 (1.26–3.03)	2.32 (1.42–3.78)	11.86 (5.22–26.93)	6.85 (3.24–14.49)
Birth weight-for-age z score	0.91 (0.79–1.05)	0.84 (0.72–0.99)	0.68 (0.51–0.91)	0.69 (0.51–0.93)
HIV-exposed	1.40 (0.97–2.02)	1.33 (0.90–1.96)	3.32 (1.69–6.53)	2.92 (1.52–5.59)
Season of birth (ref. summer)
Autumn (Mar–May)	1.20 (0.77–1.89)	1.23 (0.77–1.96)	0.63 (0.25–1.59)	0.71 (0.30–1.66)
Winter (Jun–Aug)	1.04 (0.66–1.63)	1.05 (0.66–1.68)	0.90 (0.37–2.19)	0.78 (0.33–1.84)
Spring (Sep–Nov)	1.10 (0.69–1.76)	1.13 (0.70–1.84)	1.00 (0.40–2.51)	0.69 (0.28–1.72)
Age at LRTI	1.01 (0.98–1.04)	1.01 (0.98–1.05)	0.92 (0.84–1.02)	0.90 (0.81–0.99)
Maternal characteristics
Antenatal self-reported smoking	0.91 (0.63–1.32)	0.74 (0.32–1.72)	0.21 (0.04–1.05)	0.30 (0.08–1.13)
Postnatal self-reported smoking	1.00 (0.69–1.44)	1.31 (0.58–2.99)	3.70 (0.83–16.50)	1.54 (0.46–5.13)
Household income per month (ref <1000 [ZAR])
100–5000 [ZAR]	0.88 (0.62–1.25)	0.87 (0.60–1.28)	0.54 (0.26–1.11)	0.66 (0.32–1.38)
>5000 [ZAR]	1.01 (0.59–1.73)	0.94 (0.52–1.71)	0.74 (0.22–2.44)	0.64 (0.19–2.15)
Employment	1.05 (0.76–1.46)	1.19 (0.83–1.72)	1.22 (0.60–2.48)	1.03 (0.51–2.07)
Duration exclusive breast feeding (months)	0.96 (0.88–1.04)	0.96 (0.88–1.05)	0.79 (0.65–0.96)	0.78 (0.64–0.96)

LRTI = lower respiratory tract infection; OR = odds ratio; 95% CI = 95% confidence interval; KP = Klebsiella pneumoniae; HIV = human immunodeficiency virus; ZAR= South African Rand

^⁎Adjusted for all covariates displayed in table

Bolded values indicate significant results