Aim To identify the risk factors in children under five years
of age for severe acute lower respiratory infections (ALRI),
which are the leading cause of child mortality.
Methods We performed a systematic review of published
literature available in the public domain. We conducted
a quality assessment of all eligible studies according to
GRADE criteria and performed a meta-analysis to report the
odds ratios for all risk factors identified in these studies.
Results We identified 36 studies that investigated 19 risk
factors for severe ALRI. Of these, 7 risk factors were significantly
associated with severe ALRI in a consistent manner
across studies, with the following meta-analysis estimates
of odds ratios (with 95% confidence intervals): low birth
weight 3.18 (1.02-9.90), lack of exclusive breastfeeding 2.34
(1.42-3.88), crowding – more than 7 persons per household
1.96 (1.53-2.52), exposure to indoor air pollution 1.57
(1.06-2.31), incomplete immunization 1.83 (1.32-2.52), undernutrition
– weight-for-age less than 2 standard deviations
4.47 (2.10-9.49), and HIV infection 4.15 (2.57-9.74).
Conclusion This study highlights the role of the above
seven risk factors in the development of severe pneumonia
in under-five children. In addition, it emphasizes the
need for further studies investigating other potential risk
factors. Since these risk factors are potentially preventable,
health policies targeted at reducing their prevalence provide
a basis for decreasing the burden of childhood pneumonia