Lana Tomaskovic

Bio: Lana Tomaskovic is an academic researcher from World Health Organization. The author has contributed to research in topics: Population & Poison control. The author has an hindex of 5, co-authored 5 publications receiving 863 citations.

Global estimate of the incidence of clinical pneumonia among children under five years of age

Abstract: OBJECTIVE: Clinical pneumonia (defined as respiratory infections associated with clinical signs of pneumonia, principally pneumonia and bronchiolitis) in children under five years of age is still the leading cause of childhood mortality in the world. In this paper we aim to estimate the worldwide incidence of clinical pneumonia in young children. METHODS: Our estimate for the developing world is based on an analysis of published data on the incidence of clinical pneumonia from community based longitudinal studies. Among more than 2000 studies published since 1961, we identified 46 studies that reported the incidence of clinical pneumonia, and 28 of these met pre-defined quality criteria. FINDINGS: The estimate of the median incidence from those studies was 0.28 episodes per child-year (e/cy). The 25-75% interquartile range was 0.21-0.71. We assessed the plausibility of this estimate using estimates of global mortality from acute respiratory infections and reported case fatality rates for all episodes of clinical pneumonia reported in community-based studies or the case-fatality rate reported only for severe cases and estimates of the proportion of severe cases occurring in a defined population or community. CONCLUSION: The overlap between the ranges of the estimates implies that a plausible incidence estimate of clinical pneumonia for developing countries is 0.29 e/cy. This equates to an annual incidence of 150.7 million new cases, 11-20 million (7-13%) of which are severe enough to require hospital admission. In the developed world no comparable data are available. However, large population-based studies report that the incidence of community-acquired pneumonia among children less than five years old is approximately 0.026 e/cy, suggesting that more than 95% of all episodes of clinical pneumonia in young children worldwide occur in developing countries.

Predicting the distribution of under-five deaths by cause in countries without adequate vital registration systems

Abstract: BACKGROUND: The absence of complete vital registration and atypical nature of the locations where epidemiological studies of cause of death in children are conducted make it difficult to know the true distribution of child deaths by cause in developing countries. A credible method is needed for generating valid estimates of this distribution for countries without adequate vital registration systems. METHODS: A systematic review was undertaken of all studies published since 1980 reporting under-5 mortality by cause. Causes of death were standardized across studies, and information was collected on the characteristics of each study and its population. A meta-regression model was used to relate these characteristics to the various proportional mortality outcomes, and predict the distribution in national populations of known characteristics. In all, 46 studies met the inclusion criteria. RESULTS: Proportional mortality outcomes were significantly associated with region, mortality level, and exposure to malaria; coverage of measles vaccination, safe delivery care, and safe water; study year, age of children under surveillance, and method used to establish definitive cause of death. In sub-Saharan Africa and in South Asia, the predicted distribution of deaths by cause was: pneumonia (23% and 23%), malaria (24% and <1%), diarrhoea (22% and 23%), 'neonatal and other' (29% and 52%), measles (2% and 1%). CONCLUSIONS: For countries without adequate vital registration, it is possible to estimate the proportional distribution of child deaths by cause by exploiting systematic associations between this distribution and the characteristics of the populations in which it has been studied, controlling for design features of the studies themselves.

Methodological and quality issues in epidemiological studies of acute lower respiratory infections in children in developing countries

Abstract: Acute respiratory infections are the most important single cause of global burden of disease in young children globally and a major cause of child mortality. A recent review of studies reporting the incidence of acute lower respiratory infections (ALRI) in young children in the developing world was carried out by the WHO Child Health Epidemiology Reference Group in order to inform global burden of disease estimates. The review highlighted the low number of community-based longitudinal studies of ALRI incidence in young children which met minimum quality criteria. It underscored the need to give attention to issues of study design and the reporting of a basic minimum dataset which describes circumstances under which the studies were being conducted and the key design features of the study which may influence the ALRI estimate. This paper aims to provide methodological guidelines for the design, conduct, and reporting of epidemiological studies of ALRI in under-5s in developing countries. It discusses determinants of study quality related to both study design and statistical analysis and also issues requiring further research. It is hoped that these guidelines will stimulate further work in this field and encourage the publication of reports which contain sufficient data to permit a meaningful meta-analysis of the data, thus forming the basis of more reliable future estimates of global burden of ALRI.

Incidence of acute lower respiratory infections (ALRI) in children under five years: II. Estimates for WHO regions

Abstract: We have previously reported an estimate for global acute lower respiratory infection (ALRI) incidence in young children under 5 years of age of 0.29 episodes/child-year or about 150 million new episodes each year. In this paper we aim to distribute these cases by the WHO regions of the world. This was performed by distributing episodes according to national under five child population data and data on the prevalence of exposure to major ALRI risk factors for each country then assembling these into regional estimates based on country membership of WHO regions. The risk factors most consistently reported to be associated with ALRI incidence and for which prevalence information for each country was available were malnutrition (weight-for-height less than -2 z-score), low birth weight (less than 2, 500 g), lack of breastfeeding (in first 4 months of life), crowding (5 or more persons per household) and lack of measles immunization. A review of the literature showed that relative risks for ALRI associated with these factors and which were available from multivariate analyses of longitudinal studies were about 1.8, 1.4, 1.3, 1.2 and 0.7, respectively. The estimated prevalence of exposure to these risk factors was available for more than 95% of under-fives in developing countries from various sources, mainly Demographic and Health Surveys (DHS) and Multiple Indicator Cluster Surveys (MICS). We introduced a simple model to distribute the global estimate of new ALRI episodes by WHO regions according to risk factor prevalence in each country. The ALRI incidence estimates ranked in order from highest to lowest were Sear D (0.34 episodes/child-year), Afr D (0.33), Emr D (0.32), Afr E (0.31), Sear B (0.27), Amr D (0.25), Amr B (0.24), Emr B (0.23) and Wpr B (0.22). This equates to 57.6 million new ALRI episodes per year in the WHO South East Asia region (Sear D and B), 34.5 million in the African region (Afr D and E), 27.4 million in the Western Pacific region (Wpr B) and 20.3 million in the Eastern Mediterranean region (Emr D).