Summary
Background
Lower respiratory infections are a leading cause of morbidity and mortality around
the world. The Global Burden of Diseases, Injuries, and Risk Factors (GBD) Study 2016,
provides an up-to-date analysis of the burden of lower respiratory infections in 195
countries. This study assesses cases, deaths, and aetiologies spanning the past 26
years and shows how the burden of lower respiratory infection has changed in people
of all ages.
Methods
We used three separate modelling strategies for lower respiratory infections in GBD
2016: a Bayesian hierarchical ensemble modelling platform (Cause of Death Ensemble
model), which uses vital registration, verbal autopsy data, and surveillance system
data to predict mortality due to lower respiratory infections; a compartmental meta-regression
tool (DisMod-MR), which uses scientific literature, population representative surveys,
and health-care data to predict incidence, prevalence, and mortality; and modelling
of counterfactual estimates of the population attributable fraction of lower respiratory
infection episodes due to Streptococcus pneumoniae, Haemophilus influenzae type b,
influenza, and respiratory syncytial virus. We calculated each modelled estimate for
each age, sex, year, and location. We modelled the exposure level in a population
for a given risk factor using DisMod-MR and a spatio-temporal Gaussian process regression,
and assessed the effectiveness of targeted interventions for each risk factor in children
younger than 5 years. We also did a decomposition analysis of the change in LRI deaths
from 2000–16 using the risk factors associated with LRI in GBD 2016.
Findings
In 2016, lower respiratory infections caused 652 572 deaths (95% uncertainty interval
[UI] 586 475–720 612) in children younger than 5 years (under-5s), 1 080 958 deaths
(943 749–1 170 638) in adults older than 70 years, and 2 377 697 deaths (2 145 584–2 512 809)
in people of all ages, worldwide. Streptococcus pneumoniae was the leading cause of
lower respiratory infection morbidity and mortality globally, contributing to more
deaths than all other aetiologies combined in 2016 (1 189 937 deaths, 95% UI 690 445–1 770 660).
Childhood wasting remains the leading risk factor for lower respiratory infection
mortality among children younger than 5 years, responsible for 61·4% of lower respiratory
infection deaths in 2016 (95% UI 45·7–69·6). Interventions to improve wasting, household
air pollution, ambient particulate matter pollution, and expanded antibiotic use could
avert one under-5 death due to lower respiratory infection for every 4000 children
treated in the countries with the highest lower respiratory infection burden.
Interpretation
Our findings show substantial progress in the reduction of lower respiratory infection
burden, but this progress has not been equal across locations, has been driven by
decreases in several primary risk factors, and might require more effort among elderly
adults. By highlighting regions and populations with the highest burden, and the risk
factors that could have the greatest effect, funders, policy makers, and programme
implementers can more effectively reduce lower respiratory infections among the world's
most susceptible populations.
Funding
Bill & Melinda Gates Foundation.