Browsing by Author "Mark Myatt"

Now showing 1 - 5 of 5
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    Anthropometric criteria for best-identifying children at high risk of mortality: a pooled analysis of twelve cohorts
    (2023-02-03) Tanya Khara; Mark Myatt; Kate Sadler; Paluku Bahwere; James A Berkley; James A Berkley; Robert E Black; Erin Boyd; Michel Garenne; Sheila Isanaka; Natasha Lelijveld; Christine McDonald; Andrew Mertens; Martha Mwangome; Kieran O’Brien; Heather Stobaugh; Sunita Taneja; Keith P West; André Briend
    Objective: To understand which anthropometric diagnostic criteria best discriminate higher from lower risk of death in children and explore programme implications. Design: A multiple cohort individual data meta-analysis of mortality risk (within 6 months of measurement) by anthropometric case definitions. Sensitivity, specificity, informedness and inclusivity in predicting mortality, face validity and compatibility with current standards and practice were assessed and operational consequences were modelled. Setting: Community-based cohort studies in twelve low-income countries between 1977 and 2013 in settings where treatment of wasting was not widespread. Participants: Children aged 6 to 59 months. Results: Of the twelve anthropometric case definitions examined, four (weight-forage Z-score (WAZ) <−2), (mid-upper arm circumference (MUAC) <125 mm), (MUAC < 115 mm or WAZ < −3) and (WAZ < −3) had the highest informedness in predicting mortality. A combined case definition (MUAC < 115 mm or WAZ < −3) was better at predicting deaths associated with weight-for-height Z-score <−3 and concurrent wasting and stunting (WaSt) than the single WAZ < −3 case definition. After the assessment of all criteria, the combined case definition performed best. The simulated workload for programmes admitting based on MUAC < 115 mm or WAZ < −3, when adjusted with a proxy for required intensity and/or duration of treatment, was 1·87 times larger than programmes admitting on MUAC < 115 mm alone. Conclusions: A combined case definition detects nearly all deaths associated with severe anthropometric deficits suggesting that therapeutic feeding programmes may achieve higher impact (prevent mortality and improve coverage) by using it. There remain operational questions to examine further before wide-scale adoption can be recommended.
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    Anthropometric deficits and the associated risk of death by age and sex in children aged 6-59 months: A meta-analysis
    (2023-08) Susan Thurstans; Stephanie V. Wrottesley; Bridget Fenn; Tanya Khara; Paluku Bahwere; James A. Berkley; Robert E. Black; Erin Boyd; Michel Garenne; Sheila Isanaka; Natasha Lelijveld; Christine M. McDonald; Andrew Mertens; Martha Mwangome; Kieran S. O'Brien; Heather Stobaugh; Sunita Taneja; Keith P. West; Saul Guerrero; Marko Kerac; André Briend; Mark Myatt
    Risk of death from undernutrition is thought to be higher in younger than in older children, but evidence is mixed. Research also demonstrates sex differences whereby boys have a higher prevalence of undernutrition than girls. This analysis described mortality risk associated with anthropometric deficits (wasting, underweight and stunting) in children 6-59 months by age and sex. We categorised children into younger (6-23 months) and older (24-59 months) age groups. Age and sex variations in near-term (within 6 months) mortality risk, associated with individual anthropometric deficits were assessed in a secondary analysis of multi-country cohort data. A random effects meta-analysis was performed. Data from seven low-or-middle-income-countries collected between 1977 and 2013 were analysed. One thousand twenty deaths were recorded for children with anthropometric deficits. Pooled meta-analysis estimates showed no differences by age in absolute mortality risk for wasting (RR 1.08, p = 0.826 for MUAC < 125 mm; RR 1.35, p = 0.272 for WHZ < -2). For underweight and stunting, absolute risk of death was higher in younger (RR 2.57, p < 0.001) compared with older children (RR 2.83, p < 0.001). For all deficits, there were no differences in mortality risk for girls compared with boys. There were no differences in the risk of mortality between younger and older wasted children, supporting continued inclusion of all children under-five in wasting treatment programmes. The risk of mortality associated with underweight and stunting was higher among younger children, suggesting that prevention programmes might be justified in focusing on younger children where resources are limited. There were no sex differences by age in mortality risk for all deficits.
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    Changing sex differences in undernutrition of African children: findings from Demographic and Health Surveys
    (2021-09-07) Michel Garenne; Susan Thurstans; André Briend; Carmel Dolan; Tanya Khara; Mark Myatt; Andrew Seal; Jonathan C. Wells
    The study investigates sex differences in the prevalence of undernutrition in sub-Saharan Africa. Undernutrition was defined by Z-scores using the CDC-2000 growth charts. Some 128 Demographic and Health Surveys (DHS) were analysed, totalling 700,114 children under-five. The results revealed a higher susceptibility of boys to undernutrition. Male-to-female ratios of prevalence averaged 1.18 for stunting (height-for-age Z-score <−2.0); 1.01 for wasting (weight-for-height Z-score <−2.0); 1.05 for underweight (weight-for-age Z-score <−2.0); and 1.29 for concurrent wasting and stunting (weight-for-height and height-for-age Z-scores <−2.0). Sex ratios of prevalence varied with age for stunting and concurrent wasting and stunting, with higher values for children age 0–23 months and lower values for children age 24–59 months. Sex ratios of prevalence tended to increase with declining level of mortality for stunting, underweight and concurrent wasting and stunting, but remained stable for wasting. Comparisons were made with other anthropometric reference sets (NCHS-1977 and WHO-2006), and the results were found to differ somewhat from those obtained with CDC-2000. Possible rationales for these patterns are discussed.
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    Prognostic value of different anthropometric indices over different measurement intervals to predict mortality in 6–59-month-old children
    (2023-06) André Briend; Mark Myatt; James A Berkley; Robert E Black; Erin Boyd; Michel Garenne; Natasha Lelijveld; Sheila Isanaka; Christine M McDonald; Martha Mwangwome; Kieran S O’Brien; Catherine Schwinger; Heather Stobaugh; Sunita Taneja; Keith P West; Tanya Khara
    Objective: To compare the prognostic value of mid-upper arm circumference (MUAC), weight-for-height Z-score (WHZ) and weight-for-age Z-score (WAZ) for predicting death over periods of 1, 3 and 6 months follow-up in children. Design: Pooled analysis of twelve prospective studies examining survival after anthropometric assessment. Sensitivity and false-positive ratios to predict death within 1, 3 and 6 months were compared for three individual anthropometric indices and their combinations. Setting: Community-based, prospective studies from twelve countries in Africa and Asia. Participants: Children aged 6–59 months living in the study areas. Results: For all anthropometric indices, the receiver operating characteristic curves were higher for shorter than for longer durations of follow-up. Sensitivity was higher for death with 1-month follow-up compared with 6 months by 49 % (95 % CI (30, 69)) for MUAC < 115 mm (P < 0·001), 48 % (95 % CI (9·4, 87)) for WHZ < -3 (P < 0·01) and 28 % (95 % CI (7·6, 42)) for WAZ < -3 (P < 0·005). This was accompanied by an increase in false positives of only 3 % or less. For all durations of follow-up, WAZ < -3 identified more children who died and were not identified by WHZ < -3 or by MUAC < 115 mm, 120 mm or 125 mm, but the use of WAZ < -3 led to an increased false-positive ratio up to 16·4 % (95 % CI (12·0, 20·9)) compared with 3·5 % (95 % CI (0·4, 6·5)) for MUAC < 115 mm alone. Conclusions: Frequent anthropometric measurements significantly improve the identification of malnourished children with a high risk of death without markedly increasing false positives. Combining two indices increases sensitivity but also increases false positives among children meeting case definitions.
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    Understanding Sex Differences in Childhood Undernutrition: A Narrative Review
    (2022-02-23) Susan Thurstans; Charles Opondo; Andrew Seal; Jonathan C. Wells; Tanya Khara; Carmel Dolan; André Briend; Mark Myatt; Michel Garenne; Andrew Mertens; Rebecca Sear; Marko Kerac
    : Complementing a recent systematic review and meta-analysis which showed that boys are more likely to be wasted, stunted, and underweight than girls, we conducted a narrative review to explore which early life mechanisms might underlie these sex differences. We addressed different themes, including maternal and newborn characteristics, immunology and endocrinology, evolutionary biology, care practices, and anthropometric indices to explore potential sources of sex differences in child undernutrition. Our review found that the evidence on why sex differences occur is limited but that a complex interaction of social, environmental, and genetic factors likely underlies these differences throughout the life cycle. Despite their bigger size at birth and during infancy, in conditions of food deprivation, boys experience more undernutrition from as early as the foetal period. Differences appear to be more pronounced in more severe presentations of undernutrition and in more socioeconomically deprived contexts. Boys are more vulnerable to infectious disease, and differing immune and endocrine systems appear to explain some of this disadvantage. Limited evidence also suggests that different sociological factors and care practices might exert influence and have the potential to exacerbate or reverse observed differences. Further research is needed to better understand sex differences in undernutrition and the implications of these for child outcomes and prevention and treatment programming.