Breastfeeding is associated with decreased pneumonia incidence among HIV-exposed, uninfected Kenyan infants

Ásbjörnsdóttir, Kristjana H.a; Slyker, Jennifer A.b; Weiss, Noel S.a; Mbori-Ngacha, Dorothyd; Maleche-Obimbo, Elizabethd; Wamalwa, Daltond; John-Stewart, Gracea,b,c,e

doi: 10.1097/01.aids.0000432540.59786.6d
Epidemiology and Social: CONCISE COMMUNICATION

Objective: HIV-exposed uninfected (HEU) infants have higher infectious disease morbidity and mortality than unexposed infants. We determined the incidence and risk factors for pneumonia, a leading cause of infant mortality worldwide, in a cohort of HEU infants. Identifying predictors of pneumonia among HEU infants may enable early identification of those at highest risk.

Design: A retrospective cohort of HEU infants participating in a Kenyan perinatal HIV study, enrolled between 1999 and 2002.

Methods: Infants were followed monthly from birth to 12 months. Incidence of pneumonia diagnosed at monthly study visits, sick-child visits or by means of averbal autopsy was estimated with a 14-day window for new episodes. Cox proportional hazards regression was used to identify predictors of first pneumonia occurrence.

Results: Among 388 HEU infants with 328 person-years of follow-up, the incidence of pneumonia was 900/1000 child-years [95% confidence interval (CI) 800–1000]. Maternal HIV viral load at 32 weeks’ gestation [hazard ratio 1.2 (1.0–1.5) per log10 difference] and being underweight (weight-for-age Z-score <−2) at the previous visit [hazard ratio 1.8 (1.1–2.8)] were associated with increased risk of pneumonia. Breastfed infants had a 47% lower risk of pneumonia than those never breastfed [hazard ratio 0.53 (0.39–0.73)], independent of infant growth, maternal viral load and maternal CD4%. Breastfeeding was also associated with a 74% lower risk of pneumonia-related hospitalization [hazard ratio 0.26 (0.13–0.53)].

Conclusions: The incidence of pneumonia in this cohort of HEU infants was high. Our observations suggest that maternal viral suppression and breastfeeding may reduce the burden of pneumonia among HEU infants.

Author Information

aDepartment of Epidemiology

bDepartment of Global Health

cDepartment of Pediatrics, University of Washington, Seattle, Washington USA

dDepartment of Paediatrics & Child Health, University of Nairobi, Nairobi, Kenya

eDepartment of Medicine, University of Washington, Seattle, Washington USA.

Correspondence to Kristjana Ásbjörnsdóttir, Harborview Medical Center, 325 9th Ave, Box 359931, Seattle, WA 98104, USA. Tel: +1 650 799 6700; fax: +1 206 543 4313; e-mail:

Received 18 March, 2013

Revised 23 June, 2013

Accepted 27 June, 2013

© 2013 Lippincott Williams & Wilkins, Inc.