24 research outputs found
A Growth Reference for Mid Upper Arm Circumference for Age among School Age Children and Adolescents, with Validation for Mortality in Two Cohorts
OBJECTIVES: To construct growth curves for mid-upper-arm circumference (MUAC)-for-age z score for 5-19 year olds that accord with the World Health Organization growth standards, and to evaluate their discriminatory performance for subsequent mortality.
DESIGN: Growth curve construction and longitudinal cohort study.
SETTING: United States and international growth data, and cohorts in Kenya, Uganda, and Zimbabwe.
PARTICIPANTS The Health Examination Survey (HES)/National Health and Nutrition Examination Survey (NHANES) US population datasets (age 5-25 years), which were used to construct the 2007 WHO growth reference for body mass index in this age group, were merged with an imputed dataset matching the distribution of the WHO 2006 growth standards age 2-6 years. Validation data were from 685 HIV infected children aged 5-17 years participating in the Antiretroviral Research for Watoto (ARROW) trial in Uganda and Zimbabwe; and 1741 children aged 5-13 years discharged from a rural Kenyan hospital (3.8% HIV infected). Both cohorts were followed-up for survival during one year.
MAIN OUTCOME MEASURES: Concordance with WHO 2006 growth standards at age 60 months and survival during one year according to MUAC-for-age and body mass index-for-age z scores.
RESULTS: The new growth curves transitioned smoothly with WHO growth standards at age 5 years. MUAC-for-age z scores of â2 to â3 and less thanâ3, compared with â2 or more, was associated with hazard ratios for death within one year of 3.63 (95% confidence interval 0.90 to 14.7; P=0.07) and 11.1 (3.40 to 36.0; P<0.001), respectively, among ARROW trial participants; and 2.22 (1.01 to 4.9; P=0.04) and 5.15 (2.49 to 10.7; P<0.001), respectively, among Kenyan children after discharge from hospital. The AUCs for MUAC-for-age and body mass index-for-age z scores for discriminating subsequent mortality were 0.81 (95% confidence interval 0.70 to 0.92) and 0.75 (0.63 to 0.86) in the ARROW trial (absolute difference 0.06, 95% confidence interval â0.032 to 0.16; P=0.2) and 0.73 (0.65 to 0.80) and 0.58 (0.49 to 0.67), respectively, in Kenya (absolute difference in AUC 0.15, 0.07 to 0.23; P=0.0002).
CONCLUSIONS: The MUAC-for-age z score is at least as effective as the body mass index-for-age z score for assessing mortality risks associated with undernutrition among African school aged children and adolescents. MUAC can provide simplified screening and diagnosis within nutrition and HIV programmes, and in research
A growth reference for mid upper arm circumference for age among school age children and adolescents, and validation for mortality: growth curve construction and longitudinal cohort study
Objectives
Worldwide, school age children and adolescents are vulnerable to conflict and food insecurity and HIV-infected children are increasingly surviving into adolescence. WHO recommends assessing acute malnutrition in this age group using body mass index-for-age Z scores (BMIz). For under-fives, mid upper arm circumference (MUAC) is the mainstay of community diagnosis of acute malnutrition, is simple to perform and predicts survival better than weight-for-height Z scores. MUAC is little-used in older children and adolescents because there is no accepted international reference. This study aimed to construct growth curves for MUAC-for-age Z score (MUACz) for 5-19 year olds that accord with WHO Growth Standards, and evaluate their discriminatory performance for subsequent mortality.
Design
The HES/NHANES US population datasets (age 5-25 years), which were used to construct the 2007 WHO Growth Reference for BMI in this age group, were merged with an imputed dataset matching the distribution of the WHO 2006 Growth Standards age 2-6 years. To construct standardised growth curves, we used Generalized Additive Models for Location, Scale and Shape with Box-Cox Cole Green transformation and penalized B-spline smoothing. Validation for subsequent mortality in two cohorts was done using Cox proportional hazards models for pre-defined MUACz and BMIz thresholds, with age, gender and HIV status as covariates; and estimation of the area under receiver-operating characteristic curves (AUC).
Participants
Validation data were from 685 HIV-infected children age 5ÂŹâ17 years participating in the ARROW trial in Uganda and Zimbabwe; and 1,741 children age 5â13 years discharged from a rural Kenyan hospital (3.8% HIV-infected). Both cohorts were followed up for survival during one year.
Main outcome measures
Concordance with WHO 2006 Growth Standards at age 60 months and survival during one year according to MUACz and BMIz.
Results
The new growth curves transitioned smoothly with WHO Growth Standards at age 5 years. MUACz of -2 to -3 and <-3, compared with â„-2, was associated with hazard ratios for death within one year of 3.63 (95%CI 0.90 to 14.7; P=0.07) and 11.1 (95%CI 3.40 to 36.0; P<0.0001) respectively among ARROW trial participants; and 2.22 (95%CI 1.01 to 4.9; P=0.04) and 5.15 (95%CI 2.49 to 10.7; P<0.0001) respectively among Kenyan children after discharge from hospital. The AUCs for MUACz and BMIz for discriminating subsequent mortality were 0.81 (95%CI 0.70 to 0.92) and 0.75 (95%CI 0.63 to 0.86) in the ARROW trial (absolute difference 0.06 (95% CI -0.032 to 0.16; P=0.2); and 0.73 (95%CI 0.65 to 0.80) and 0.58 (95% CI 0.49 to 0.67) respectively in Kenya (absolute difference in AUC 0.15 (95% CI 0.07 to 0.23; P=0.0002).
Conclusions
MUACz is at least as effective as BMIz for assessing mortality risks associated with undernutrition among African school-aged children and adolescents. MUAC can provide simplified screening and diagnosis within nutrition and HIV programmes, and in research
Comparison of acoustic and traditional point count methods to assess bird diversity and composition in the Aberdare National Park, Kenya
Afromontane forests, like those in the Aberdare National Park (ANP) in Kenya, sustain unique avifaunal assemblages. There is a growing need for biodiversity inventories for Afromontane forests, especially through the utilisation of unskilled observers. Acoustic surveys are a potential aid to this, but more comparisons of this technique with that of traditional point counts are needed. We conducted a systematic survey of the ANP avifauna, assessing whether acoustic and traditional surveys resulted in different species richness scores, and whether this varied with habitat and species characteristics. We also investigated the role of habitat and elevation in driving variation in species richness. The ANP provides habitat types including scrub, moorland, montane, hagenia and bamboo forests. Overall, the surveys yielded 101 identified species. The acoustic method resulted in higher species richness scores compared to the traditional method across all habitats, and the relative performance of the two methods did not vary with habitat type or visibility. The methods detected different species, suggesting that they should be used together to maximise the range of species recorded. We found that habitat type was the primary driver of variation in species richness, with scrub and montane forest having higher species richness scores than other habitats
Fighting Capital Flight in Africa: Evidence from Bundling and Unbundling Governance
This study investigates the effect of governance on capital flight by bundling and unbundling governance. The empirical evidence is based on 37 African countries for the period 1996â2010 and the Generalised Method of Moments. Governance is bundled by principal component analysis, namely: (i) political governance from political stability and âvoice and accountabilityâ; (ii) economic governance from government effectiveness and regulation quality and (iii) institutional governance from corruption-control and the rule of law. The following findings are established. (i) Political stability and âvoice and accountabilityâ reduce capital flight while the collective effect of political governance is not significant. (ii) Economic governance increases capital flight whereas the individual effects of regulation quality and government effectiveness are not significant. (iii) Corruption-control and institutional governance negatively affect capital flight whereas the impact of the rule of law is not significant. (iv) Taken together, Corruption-control is the most effective governance weapon in the fight against capital flight. (v) Priority in the Washington Consensus is more effective at fighting capital flight compared to the Beijing Model. Policy implications are discussed
The PREDICTS database: a global database of how local terrestrial biodiversity responds to human impacts
Biodiversity continues to decline in the face of increasing anthropogenic pressures
such as habitat destruction, exploitation, pollution and introduction of
alien species. Existing global databases of speciesâ threat status or population
time series are dominated by charismatic species. The collation of datasets with
broad taxonomic and biogeographic extents, and that support computation of
a range of biodiversity indicators, is necessary to enable better understanding of
historical declines and to project â and avert â future declines. We describe and
assess a new database of more than 1.6 million samples from 78 countries representing
over 28,000 species, collated from existing spatial comparisons of
local-scale biodiversity exposed to different intensities and types of anthropogenic
pressures, from terrestrial sites around the world. The database contains
measurements taken in 208 (of 814) ecoregions, 13 (of 14) biomes, 25 (of 35)
biodiversity hotspots and 16 (of 17) megadiverse countries. The database contains
more than 1% of the total number of all species described, and more than
1% of the described species within many taxonomic groups â including flowering
plants, gymnosperms, birds, mammals, reptiles, amphibians, beetles, lepidopterans
and hymenopterans. The dataset, which is still being added to, is
therefore already considerably larger and more representative than those used
by previous quantitative models of biodiversity trends and responses. The database
is being assembled as part of the PREDICTS project (Projecting Responses
of Ecological Diversity In Changing Terrestrial Systems â www.predicts.org.uk).
We make site-level summary data available alongside this article. The full database
will be publicly available in 2015
Notes on the behaviour and ecology of Sharpe's Longclaw, a threatened Kenyan grassland endemic
Habitat selection and conservation of Sharpe's longclaw (Macronyx sharpei), a threatened Kenyan grassland endemic.
A growth reference for mid upper arm circumference for age among school age children and adolescents, and validation for mortality: growth curve construction and longitudinal cohort study
Objectives Worldwide, school age children and adolescents are vulnerable to conflict and food insecurity and HIV-infected children are increasingly surviving into adolescence. WHO recommends assessing acute malnutrition in this age group using body mass index-for-age Z scores (BMIz). For under-fives, mid upper arm circumference (MUAC) is the mainstay of community diagnosis of acute malnutrition, is simple to perform and predicts survival better than weight-for-height Z scores. MUAC is little-used in older children and adolescents because there is no accepted international reference. This study aimed to construct growth curves for MUAC-for-age Z score (MUACz) for 5-19 year olds that accord with WHO Growth Standards, and evaluate their discriminatory performance for subsequent mortality. Design The HES/NHANES US population datasets (age 5-25 years), which were used to construct the 2007 WHO Growth Reference for BMI in this age group, were merged with an imputed dataset matching the distribution of the WHO 2006 Growth Standards age 2-6 years. To construct standardised growth curves, we used Generalized Additive Models for Location, Scale and Shape with Box-Cox Cole Green transformation and penalized B-spline smoothing. Validation for subsequent mortality in two cohorts was done using Cox proportional hazards models for pre-defined MUACz and BMIz thresholds, with age, gender and HIV status as covariates; and estimation of the area under receiver-operating characteristic curves (AUC). Participants Validation data were from 685 HIV-infected children age 5ÂŹâ17 years participating in the ARROW trial in Uganda and Zimbabwe; and 1,741 children age 5â13 years discharged from a rural Kenyan hospital (3.8% HIV-infected). Both cohorts were followed up for survival during one year. Main outcome measures Concordance with WHO 2006 Growth Standards at age 60 months and survival during one year according to MUACz and BMIz. Results The new growth curves transitioned smoothly with WHO Growth Standards at age 5 years. MUACz of -2 to -3 and <-3, compared with â„-2, was associated with hazard ratios for death within one year of 3.63 (95%CI 0.90 to 14.7; P=0.07) and 11.1 (95%CI 3.40 to 36.0; P<0.0001) respectively among ARROW trial participants; and 2.22 (95%CI 1.01 to 4.9; P=0.04) and 5.15 (95%CI 2.49 to 10.7; P<0.0001) respectively among Kenyan children after discharge from hospital. The AUCs for MUACz and BMIz for discriminating subsequent mortality were 0.81 (95%CI 0.70 to 0.92) and 0.75 (95%CI 0.63 to 0.86) in the ARROW trial (absolute difference 0.06 (95% CI -0.032 to 0.16; P=0.2); and 0.73 (95%CI 0.65 to 0.80) and 0.58 (95% CI 0.49 to 0.67) respectively in Kenya (absolute difference in AUC 0.15 (95% CI 0.07 to 0.23; P=0.0002). Conclusions MUACz is at least as effective as BMIz for assessing mortality risks associated with undernutrition among African school-aged children and adolescents. MUAC can provide simplified screening and diagnosis within nutrition and HIV programmes, and in research