Environmental temperature and growth faltering in African children: a cross-sectional study

High wet-bulb temperatures, time allocation, and diurnal patterns of breastfeeding in Bangladeshi fisher-traders

BACKGROUND

Climate change is a growing threat to population health, with dangerous combinations of heat and humidity increasing in frequency, particularly in South Asia. Evidence suggests that high temperatures and heat stress influence breastfeeding behaviour and may lead to suboptimal infant and young child nutrition.

AIM

Few studies have quantified the relationship between ambient heat and breastfeeding. Here we evaluate associations between wet-bulb temperature and daily breastfeeding patterns in a rural community in Bangladesh.

SUBJECTS AND METHODS

We used 23 months of daily time-diary data from 68 maternal-child dyads and regional wet-bulb temperatures to test the hypothesis that increased heat and humidity negatively influence breastfeeding outcomes among Shodagor fisher-traders.

RESULTS

We found that higher wet-bulb temperatures predicted reduced daily breastfeeding time allocation, particularly among fishers, and drove shifts towards increased night-time and decreased mid/late morning feeding. Maternal occupation and the interaction of child age with heat strongly influenced diurnal breastfeeding patterns.

CONCLUSION

These results highlight an important role of maternal work on infants' vulnerability to environmental stress. Dyads' ability to behaviourally compensate for extreme heat may be constrained by extended heatwaves, humidity, and economic circumstances, suggesting that climate change will likely exacerbate heat-related risks to global child health going forward.

Effects of Thermal Environment on Bone Microenvironment: A Narrative Review

Research findings reveal that thermal environments precisely regulate the skeletal system through a triple regulation of "structural morphology-cellular dynamics-molecular mechanisms": At the tissue morphology level, moderate heat exposure can promote increased bone density and longitudinal growth, as well as improved fracture load and yield point, but may negatively affect geometric shape and cortical bone thickness. Continuous high-temperature exposure harms bone structure, manifested as changes in biomechanical characteristics such as decreased toughness and rigidity. At the cellular level, thermal environments directly affect the proliferation/apoptosis balance of osteoblasts and osteoclasts, and by regulating osteocyte network activity and bone marrow mesenchymal stem cell fate decisions, these four cell populations form temperature-dependent metabolic regulatory circuits. At the molecular dimension, heat stress can activate the release of neural factors such as CGRP and NPY, which possess dual regulatory functions promoting both bone formation and resorption; simultaneously achieving coordinated regulation of angiogenesis and fat inhibition through VEGF and TGFβ. The thermal environment-bone regulatory mechanisms revealed in this study have important translational value: they not only provide theoretical basis for biomechanical protection strategies for high-temperature workers and athletes, but also offer innovative entry points for analyzing the pathological mechanisms of heat stroke secondary bone injury and osteoporosis through heat stress-related signaling pathways, while establishing a theoretical foundation for the development of temperature-responsive functionalized biomaterials in bone tissue engineering.

What works for reducing stunting in low-income and middle-income countries? Cumulative learnings from the Global Stunting Exemplars Project

BACKGROUND

Impaired linear growth and stunting in children under 5 y is a marker of multiple deprivations in low-income and middle-income countries.

OBJECTIVES

We aimed to assess drivers and policies influencing improvements in linear growth and stunting reduction in 10 countries with annual rates of reduction in childhood stunting averaging 1.1% (range: 0.4%-1.7%) at national-level or subnational-level, and to improve a framework of action for other countries to follow.

METHODS

We used mixed methods to assess trends and patterns of improvement in linear growth in children under 5 y using available household-level data and in-depth analysis of programs and their implementation. We assessed patterns of change with multivariate regression analyses of risk factors driving stunting and affecting change. We compared results from the Oaxaca-Blinder decomposition analyses using a hierarchical approach and retrospectively assessed the appropriateness of a previously proposed 10-step process for country-level planning and implementation processes. Limited data precluded robust serial assessment of dietary intake at individual level for children and mothers.

RESULTS

Rapid reduction in childhood stunting is possible and findings across exemplar countries underscore the benefits of indirect and direct interventions in health and other social sectors. These include programs focusing on poverty alleviation; water, sanitation, and hygiene; promotion of girls' education and empowerment; and maternal nutrition. The potential benefits of family planning programs and factors contributing to gains in maternal nutrition were noted. In malarial endemic areas, malaria control programs were associated with improved childhood growth, and patterns of growth indicated continued benefits of childhood disease prevention and management strategies.

CONCLUSIONS

A systematic, evidence-informed approach to improve maternal and child health and nutrition is feasible and, with targeting, can accelerate reduction in linear growth faltering in childhood.

Extreme heat exposure in the first 1000 days: Implications for childhood stunting in Bangladesh

OBJECTIVES

Stunting is a critical public health issue in Bangladesh, a country highly vulnerable to climate change and increased extreme heat exposure. Limited research has examined the relationship between extreme heat during the first 1000 days of life and stunting. This study provides the first evidence from Bangladesh on the likelihood of stunting among children aged 24-59 months following exposure to extreme heat during this crucial developmental period.

STUDY DESIGN

The study utilized district-level panel data from the 2012 and 2019 Multiple Indicator Cluster Surveys, comprising of 24,035 children aged 24-59 months, paired with daily temperature records reflecting conditions from the child's firth 1000 days.

METHODS

A multilevel logistic regression model with district-level random effects assessed the relationship between extreme heat exposure and stunting.

RESULTS

A 1 % increase in extreme heat days during the first 1000 days of life was associated with higher odds of stunting (adjusted odds ratio [AOR] 1.56, 95 % confidence interval [CI] 1.25-1.95, p < 0.0001) at 24-59 months of age. Post-birth exposure to extreme heat showed a stronger association with stunting (AOR 1.67, 95 % CI 1.37-2.03, p = 0.063) than in utero exposure (AOR 1.28, 95 % CI 1.14-1.44, p < 0.0001).

CONCLUSION

Escalating extreme heat threatens decades of progress in reducing stunting in Bangladesh. Mitigation efforts targeting the first 1000 days of life are critical, alongside further research to disentangle the specific effects of extreme heat on child growth within the broader context of climate change.

Precipitation, temperature, and child undernutrition: evidence from the Mali demographic and health surveys 2012-2013 and 2018

BACKGROUND

Undernutrition among children remains a severe burden in Sub-Saharan Africa. Climate change is widely recognized as a major obstacle to improving children's nutritional outcomes. Mali, a landlocked country in West Africa, has one of the highest prevalence of child undernutrition in the region and is also considered one of the most vulnerable nations to climate change globally. This study, therefore, aimed to assess the effects of precipitation and temperature on child undernutrition in Mali, with a focus on climatic differences between the southern and northern regions.

METHODS

We pooled the two most recent cross-sectional datasets from the Mali Demographic and Health Surveys (DHS) 2012-2013 and DHS 2018, integrating them with climatic variables at the DHS cluster level. The study included data from 12,281 children under five years of age. Precipitation and temperature data were extracted from the Advancing Research on Nutrition and Agriculture's DHS-Geographical Information System database, which provides a comprehensive range of climatic and geographic variables at the DHS cluster level. We assessed the effects of precipitation and temperature over periods of three months, six months, one year, and two years before the survey on child undernutrition using multivariable multilevel logistic regression models.

RESULTS

In southern Mali, 25.0% of children under five were stunted (95% CI 23.7-26.3%), 24.9% were underweight (95% CI 23.7-26.1%), and 9.3% were wasted (95% CI 8.5-10.1%). In northern Mali, the prevalence rates were higher: 29.6% for stunting (95% CI 27.0-32.1%), 28.7% for underweight (95% CI 26.0-31.3%), and 10.5% for wasting (95% CI 8.8-12.3%). From the pooled data analysis, we found that higher average monthly rainfall over the last three months (AOR = 0.977, p = 0.012) and six months (AOR = 0.974, p = 0.003) preceding the survey was significantly associated with lower odds of wasting in northern Mali, predominantly comprising desert areas. Moreover, in addition to reducing wasting, rainfall over the one year (AOR = 0.985, p = 0.010) and two years (AOR = 0.984, p = 0.009) prior to the survey showed a significant effect in reducing the odds of underweight among children in the north.

CONCLUSIONS

Increased precipitation had a beneficial effect on children's nutritional status, particularly in the northern part of Mali, where water scarcity is a persistent challenge. Amid growing concerns about declining rainfall due to climate change, the risk of child undernutrition is expected to rise in the northern part. To address this escalating threat, it is crucial to implement effective and timely measures to mitigate the impacts of climate change and improve children's nutrition.

Drivers of stunting and wasting across serial cross-sectional household surveys of children under 2 years of age in Pakistan: potential contribution of ecological factors

BACKGROUND

The impact of direct and indirect drivers on linear growth and wasting in young children is of public health interest. Although the contributions of poverty, maternal education, empowerment, and birth weight to early childhood growth are well recognized, the contribution of environmental factors like heat, precipitation, agriculture outputs, and food security in comparable datasets is less well established.

OBJECTIVES

This study aims to investigate the association of length-for-age z-score (LAZ) and weight-for-length z-score (WLZ) with various indicators among children aged under 2 y in Pakistan using representative household-level nutrition surveys and ecological datasets.

METHODS

Using geo-tagged metadata from Pakistan's 2011 and 2018 National Nutrition Surveys, anthropometric data from 29,887 children (9231 from 2011 and 20,656 from 2018) were analyzed. Dietary intake and food security data for 140 districts were linked to gridded data on temperature, precipitation and soil moisture, and district measures of agriculture production of edible crops. Multiple linear regressions assessed factors associated with LAZ and WLZ in index children.

RESULTS

LAZ was positively associated with improved socioeconomic conditions (β = 0.06), food security (β = 0.10), birth size (β = 0.26), maternal age (β = 0.02), body mass index (β = 0.02), height (β = 0.02), and dietary score (β = 0.03). Negative associations with LAZ were found for increased temperature, precipitation, diarrhea, household crowding, and parity. Similar patterns were observed with WLZ for higher surface temperatures and precipitation was associated with declines in linear growth, alongside increased diarrhea prevalence and higher maternal parity.

CONCLUSIONS

Apart from recognized multifactorial drivers of stunting and wasting among children such as poverty, food insecurity, and maternal undernutrition, our analysis suggests the potential independent association with climatic factors such as heat and excess precipitation over time. These findings underscore the need for further research and the potential integration of climatic mitigation and adaptation with nutrition response strategies.

Exposure to climate change-related extreme events in the first year of life and occurrence of infant wheezing

INTRODUCTION

Climate change increases the intensity and frequency of extreme events, which will most impact younger generations. Within the NINFEA birth cohort, we investigated the relationship between exposure to such events during the first year of life and infant respiratory health.

METHODS

The NINFEA cohort study recruited pregnant women across 11 years in Italy, allowing for climatic variability exploitation by birth place and time. We combined geocoded addresses with climate data, to derive children's cumulative exposure to the following extreme events during their first year: (i) heatwaves (i.e. 3 + consecutive days, with maximum temperature > 35 °C); (ii) days with wildfire PM2.5 >15 μg/m3 and (iii) daily precipitation > 100 mm; (iv) months with exceptional drought. Logistic regression models estimated the relationship between each exposure and wheezing at 6-18 months, adjusting for individual and contextual factors.

RESULTS

Wheezing prevalence in the cohort was 17.6%. The exposure to each additional heatwave in the first year of life increased wheezing risk by 16%, with an odds ratio (OR) of 1.16 and a 95% Confidence Interval (CI) of 1.00;1.35. The OR for each month of extreme drought exposure was 1.10, 95%CI 0.95; 1.26. Results for wildfire PM2.5 were unclear with wider confidence intervals (OR for each high exposure day:1.36, 95% CI 0.85; 2.16). Wheezing was not associated with extreme precipitation.

CONCLUSIONS

Exposure to multiple extreme events, especially heatwaves, in the first year of life is associated with later infant respiratory health suggesting the need to implement climate change mitigation policies to protect long-term health.

Ethnicity and anthropometric deficits in children: A cross-sectional analysis of national survey data from 18 countries in sub-Saharan Africa

Child anthropometric deficits remain a major public health problem in Sub-Saharan Africa (SSA) and are a key target of the UN Sustainable Development Goals (SDGs). The SDGs recommend disaggregation of health indicators by ethnic group. However, few studies have assessed how ethnicity is associated with anthropometric deficits across SSA. Data were extracted from 37 georeferenced Demographic and Health Surveys carried out during 2006-2019 across SSA that recorded anthropometric data for children aged <5 years. In a cross-sectional analysis, the odds of stunting (low height-for-age), wasting (low weight-for-height) and underweight (low weight-for-age) were modelled in relation to ethnic group using a generalised linear hierarchical mixed-effects model, controlling for survey design and environmental, socioeconomic and clinical variables. The study population comprised 138,312 children spanning 45 ethnic groups across 18 countries. In pairwise comparisons (accounting for multiple comparisons) between ethnic groups, height-for-age z-scores differed by at least 0.5 standard deviations in 29% of comparisons, weight-for-height z-scores in 36% of comparisons and weight-for-age z-scores in 20% of comparisons. Compared to a reference group of Fula children (the largest ethnic group), ethnic group membership was associated with both increases and decreases in growth faltering, ranging from a 69% reduction to a 32% increase in odds of stunting (Igbo: adjusted odds ratio (aOR) 0.31, 95% confidence intervals (CI) 0.27-0.35, p<0.0001; Hausa: aOR 1.32, 95% CI 1.21-1.44, p<0.0001); a 13% to 87% reduction in odds of wasting (Mandinka: aOR 0.87, 95% CI 0.76-0.99, p = 0.034; Bamileke: aOR 0.13, 95% CI 0.05-0.32, p<0.0001) and an 85% reduction to 13% increase in odds of underweight (Bamileke: aOR 0.15, 95% CI 0.08-0.29, p<0.0001; Hausa: aOR 1.13, 95% CI 1.03-1.24, p = 0.010). Major ethnic disparities in stunting, wasting and underweight were observed across 18 countries in SSA. Understanding and accounting for these differences is essential to support progress monitoring and targeting of nutrition interventions in children.

Prevalence and determinants of double and triple burden of malnutrition among mother-child pairs in Malawi: a mapping and multilevel modelling study

OBJECTIVE

To establish the prevalence of double burden of malnutrition (DBM) and triple burden of malnutrition (TBM) among mother-child pairs in Malawi and explore their geographical distribution and associated multilevel factors.

DESIGN

Cross-sectional study using secondary data from the 2015-2016 Malawi Demographic and Health Survey using a mixed effects binomial model to identify multilevel factors associated with DBM and TBM. Georeferenced covariates were used to map the predicted prevalence of DBM and TBM.

SETTING

All twenty-eight districts in Malawi.

PARTICIPANTS

Mother-child pairs with mothers aged 15-49 years and children aged below 60 months (n 4618 pairs) for DBM and between 6 and 59 months (n 4209 pairs) for TBM.

RESULTS

Approximately 5·5 % (95% confidence interval (CI): 4·7 %, 6·4 %) of mother-child pairs had DBM, and 3·1 % (95 % CI: 2·5 %, 4·0 %) had TBM. The subnational-level prevalence of DBM and TBM was highest in cities. The adjusted odds of DBM were threefold higher (adjusted Odds Ratio, AOR: 2·8, 95 % CI: 1·1, 7·3) with a higher proportion of wealthy households in a community. The adjusted odds of TBM were 60 % lower (AOR: 0·4; 95 % CI: 0·2, 0·8) among pairs where the women had some education compared with women with no education.

CONCLUSIONS

Although the prevalence of DBM and TBM is currently low in Malawi, it is more prevalent in pairs with women with no education and in relatively wealthier communities. Targeted interventions should address both maternal overnutrition and child undernutrition in cities and these demographics.

Effect of heat stress in the first 1000 days of life on fetal and infant growth: a secondary analysis of the ENID randomised controlled trial

BACKGROUND

The intersecting crises of climate change, food insecurity, and undernutrition disproportionately affect children. Understanding the effect of heat on growth from conception to 2 years of age is important because of mortality and morbidity implications in the near term and over the life course.

METHODS

In this secondary analysis, we used longitudinal pregnancy cohort data from the Early Nutrition and Immunity Development (ENID) randomised controlled trial in West Kiang, The Gambia, which occurred between Jan 20, 2010, and Feb 10, 2015. The ENID trial assessed micronutrient supplementation in the first 1000 days of life starting from 20 weeks' gestation, during which anthropometric measurements were collected prospectively. We used multivariable linear regression to assess the effect of heat stress (defined by Universal Thermal Climate Index [UTCI]) on intrauterine growth restriction based on length-for-gestational age Z score (LGAZ), weight-for-gestational age Z score (WGAZ), and head circumference-for-gestational age Z score (HCGAZ) at birth, and assessed for effect modification of supplement intervention on the relationship between heat stress and infant anthropometry. We used multivariable, multilevel linear regression to evaluate the effect of heat stress on infant growth postnatally based on weight-for-height Z score (WHZ), weight-for-age Z score (WAZ), and height-for-age Z score (HAZ) from 0 to 2 years of age.

FINDINGS

Complete data were available for 668 livebirth outcomes (329 [49%] female infants and 339 [51%] male infants). With each 1°C increase in mean daily maximum UTCI exposure, in the first trimester, we observed a reduction in WGAZ (-0·04 [95% CI -0·09 to 0·00]), whereas in the third trimester, we observed an increase in HCGAZ (0·06 [95% CI 0·00 to 0·12]), although 95% CIs included 0. Maternal protein-energy supplementation in the third trimester was associated with reduced WGAZ (-0·16 [-0·30 to -0·02]) with each 1°C increase in mean daily maximum UTCI exposure, while no effect of heat stress on WGAZ was found with either standard care (iron and folate) or multiple micronutrient supplementation. For the postnatal analysis, complete anthropometric data at 2 years were available for 645 infants (316 [49%] female infants and 329 [51%] male infants). Postnatally, heat stress effect varied by infant age, with infants aged 6-18 months being the most affected. In infants aged 12 months exposed to a mean daily UTCI of 30°C (preceding 90-day period) versus 25°C UTCI, we observed reductions in mean WHZ (-0·43 [95% CI -0·57 to -0·29]) and mean WAZ (-0·35 [95% CI -0·45 to -0·26]). We observed a marginal increase in HAZ with increasing heat stress exposure at age 6 months, but no effect at older ages.

INTERPRETATION

Our results suggest that heat stress impacts prenatal and postnatal growth up to 2 years of age but sensitivity might vary by age. In the context of a rapidly warming planet, these findings could have short-term and long-term health effects for the individual, and immediate and future implications for public child health.

FUNDING

Wellcome Trust.

Effects of ambient heat exposure on risk of all-cause mortality in children younger than 5 years in Africa: a pooled time-series analysis

BACKGROUND

Reducing child mortality is a Sustainable Development Goal, and climate change constitutes numerous challenges for Africa. Previous research has shown an association between leading causes of child mortality and climate change. However, few studies have examined these effects in detail. We aimed to explore the effects of ambient heat on neonate, post-neonate, and child mortality rates.

METHODS

For this pooled time-series analysis, health data were obtained from the International Network for the Demographic Evaluation of Populations and Their Health (INDEPTH) Health and Demographic Surveillance System. We included data from 29 settlements from 13 countries across Africa, collected via monthly surveys from Jan 1, 1993, to Dec 31, 2016. Climate data were obtained from ERA5, collected from Jan 1, 1991, to Dec 31, 2019. We pooled these data for monthly mean daily maximum wet bulb globe temperature (WBGT) and downscaled to geolocations. Due to data heaping, we pooled our health data on a monthly temporal scale and a spatial scale into six different climate regions (ie, Sahel [ie, Burkina Faso and northern Ghana], Guinea [ie, southern Ghana, Côte d'Ivoire, and Nigeria], Senegal and The Gambia, eastern Africa [ie, Kenya, Malawi, Tanzania, Mozambique, and Uganda], South Africa, and Ethiopia). Our outcomes were neonate (ie, younger than 28 days), post-neonate (ie, aged 28 days to 1 year), and child (ie, older than 1 year and younger than 5 years) mortality. To assess the association between WBGT and monthly all-cause mortality, we used a time-series regression with a quasi-Poisson, polynomial-distributed lag model.

FINDINGS

Between Jan 1, 1993, and Dec 31, 2016, there were 44 909 deaths in children younger than 5 years across the 29 sites in the 13 African countries: 10 078 neonates, 14 141 post-neonates, and 20 690 children. We observed differences in the association of heat with neonate, post-neonate, and child mortality by study region. For example, for Ethiopia, the relative risk ratio of mortality at the 95th percentile compared with median heat exposure during the study period was 1·14 (95% CI 1·06-1·23) for neonates, 0·99 (0·90-1·07) for post-neonates, and 0·79 (0·73-0·87) for children. Across the whole year, there was a significant increase in the relative risk of increased mortality for children in eastern Africa (relative risk 1·27, 95% CI 1·19-1·36) and Senegal and The Gambia (1·11, 1·04-1·18).

INTERPRETATION

Our results show that the influence of extreme heat on mortality risk in children younger than 5 years varies by age group, region, and season. Future research should explore potentially informative ways to measure subtleties of heat stress and the factors contributing to vulnerability.

FUNDING

EU Horizons as part of the Heat Indicators for Global Health (HIGH) Horizons project.

A scoping review on heat indices used to measure the effects of heat on maternal and perinatal health

A previous systematic review has shown associations between exposure to high temperatures and negative birth outcomes. To date, a scoping review for heat indices and their use to measure effects of heat on maternal and perinatal health has not been considered.

Objectives

To provide a scoping review on heat stress and indices for those interested in the epidemiology and working in extreme heat and maternal perinatal health.

Methods

This study is a scoping review based on a previous review guided by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for scoping reviews. It identifies the main ways heat stress through different heat indices impacts maternal and perinatal health in available literature. For documents that met the inclusion criteria, we extracted 23 publications.

Results

We find four heat indices: heat index, apparent temperature, wet bulb globe temperature and universal thermal climate index. Exposure to elevated levels of heat stress can be associated with preterm birth. In addition, the more intense and prolonged duration of exposure to heat stress, the greater the risk of stillbirth. Negative birth outcomes can occur from change in hormonal levels (ie, cortisol), dehydration and blood flow diversion away from the placenta and fetus when suffering from heat stress. All studies demonstrate that certain socioeconomic factors influence the effect of heat on maternal and perinatal health outcomes.

Conclusion

We make three suggestions based on the results: (1) heat indices should be standardised across studies and explained. (2) An increased number of perinatal and maternal health outcomes explored. Finally, (3) enhanced collaboration across climate and health to improve understanding.

Statistical modeling of maximum temperature in Guinea

A statistical analysis of maximum temperature from twelve weather stations in parts of Guinea is provided. Using maximum likelihood estimation, maximum temperature data was fitted by the Generalized Extreme Value distribution. Data from all of the twelve stations were adequately fit by the Generalized Extreme Value distribution. Return level estimates are provided. Significant trends in maximum temperature were found for four of the stations. The four stations exhibited significant positive trends at the 5% significance level.

Geographical variation in hotspots of stunting among under-five children in Ethiopia: A geographically weighted regression and multilevel robust Poisson regression analysis

INTRODUCTION

Childhood stunting is a global public health concern, associated with both short and long-term consequences, including high child morbidity and mortality, poor development and learning capacity, increased vulnerability for infectious and non-infectious disease. The prevalence of stunting varies significantly throughout Ethiopian regions. Therefore, this study aimed to assess the geographical variation in predictors of stunting among children under the age of five in Ethiopia using 2019 Ethiopian Demographic and Health Survey.

METHOD

The current analysis was based on data from the 2019 mini Ethiopian Demographic and Health Survey (EDHS). A total of 5,490 children under the age of five were included in the weighted sample. Descriptive and inferential analysis was done using STATA 17. For the spatial analysis, ArcGIS 10.7 were used. Spatial regression was used to identify the variables associated with stunting hotspots, and adjusted R2 and Corrected Akaike Information Criteria (AICc) were used to compare the models. As the prevalence of stunting was over 10%, a multilevel robust Poisson regression was conducted. In the bivariable analysis, variables having a p-value < 0.2 were considered for the multivariable analysis. In the multivariable multilevel robust Poisson regression analysis, the adjusted prevalence ratio with the 95% confidence interval is presented to show the statistical significance and strength of the association.

RESULT

The prevalence of stunting was 33.58% (95%CI: 32.34%, 34.84%) with a clustered geographic pattern (Moran's I = 0.40, p<0.001). significant hotspot areas of stunting were identified in the west and south Afar, Tigray, Amhara and east SNNPR regions. In the local model, no maternal education, poverty, child age 6-23 months and male headed household were predictors associated with spatial variation of stunting among under five children in Ethiopia. In the multivariable multilevel robust Poisson regression the prevalence of stunting among children whose mother's age is >40 (APR = 0.74, 95%CI: 0.55, 0.99). Children whose mother had secondary (APR = 0.74, 95%CI: 0.60, 0.91) and higher (APR = 0.61, 95%CI: 0.44, 0.84) educational status, household wealth status (APR = 0.87, 95%CI: 0.76, 0.99), child aged 6-23 months (APR = 1.87, 95%CI: 1.53, 2.28) were all significantly associated with stunting.

CONCLUSION

In Ethiopia, under-five children suffering from stunting have been found to exhibit a spatially clustered pattern. Maternal education, wealth index, birth interval and child age were determining factors of spatial variation of stunting. As a result, a detailed map of stunting hotspots and determinants among children under the age of five aid program planners and decision-makers in designing targeted public health measures.

Critical research gaps in treating growth faltering in infants under 6 months: A systematic review and meta-analysis

In 2020, 149.2 million children worldwide under 5 years suffered from stunting, and 45.4 million experienced wasting. Many infants are born already stunted, while others are at high risk for growth faltering early after birth. Growth faltering is linked to transgenerational impacts of poverty and marginalization. Few interventions address growth faltering in infants under 6 months, despite a likely increasing prevalence due to the negative global economic impacts of the COVID-19 pandemic. Breastfeeding is a critical intervention to alleviate malnutrition and improve child health outcomes, but rarely receives adequate attention in growth faltering interventions. A systematic review and meta-analysis were undertaken to identify and evaluate interventions addressing growth faltering among infants under 6 months that employed supplemental milks. The review was carried out following guidelines from the USA National Academy of Medicine. A total of 10,405 references were identified, and after deduplication 7390 studies were screened for eligibility. Of these, 227 were assessed for full text eligibility and relevance. Two randomized controlled trials were ultimately included, which differed in inclusion criteria and methodology and had few shared outcomes. Both studies had small sample sizes, high attrition and high risk of bias. A Bangladeshi study (n = 153) found significantly higher rates of weight gain for F-100 and diluted F-100 (DF-100) compared with infant formula (IF), while a DRC trial (n = 146) did not find statistically significant differences in rate of weight gain for DF-100 compared with IF offered in the context of broader lactation and relactation support. The meta-analysis of rate of weight gain showed no statistical difference and some evidence of moderate heterogeneity. Few interventions address growth faltering among infants under 6 months. These studies have limited generalizability and have not comprehensively supported lactation. Greater investment is necessary to accelerate research that addresses growth faltering following a new research framework that calls for comprehensive lactation support.

Global warming may significantly increase childhood anemia burden in sub-Saharan Africa

Childhood anemia constitutes a global public health problem, especially in low- and middle-income countries (LMICs). However, it remains unknown whether global warming has an impact on childhood anemia. Here, we examined the association between annual temperatures and childhood anemia prevalence in sub-Saharan Africa and then projected childhood anemia burden attributable to climate change. Each 1°C increment in annual temperature was associated with increased odds of childhood anemia (odd ratio = 1.138, 95% confidence interval: 1.134-1.142). Compared with the baseline period (1985-2014), the attributable childhood anemia cases would increase by 7,597 per 100,000 person-years under a high-emission scenario in the 2090s, which would be almost 2-fold and over 3-fold more than those projected in moderate- and low-emission scenarios. Our results reveal the vulnerabilities and inequalities of children for the excess burden of anemia due to climate warming and highlight the importance of climate mitigation and adaptation strategies in LMICs.

The association of sociodemographic, nutrition, and sanitation on stunting in children under five in rural area of West Java Province in Indonesia

Background

The prevalence of stunting in Indonesia has decreased gradually. The strategy to reduce stunting is currently prioritized on improving socio-economic levels, fulfilling food intake, and sanitation conditions. This study aims to analyze the association between sociodemographics, nutrition, and sanitation on stunting in rural West Java Province in Indonesia.

Design and methods

A cross-sectional study was conducted in May-August 2022 among 247 mother-children pairs, selected by systematic random sampling from a rural area of West Java Province in Indonesia. The sociodemographic characteristics were measured using a structured questionnaire. The nutritional status of the children under five was assessed by length/height-for-age (HAZ), and was calculated using WHO Anthro software. Sanitation is assessed using observation and interviews with a structured questionnaire.

Results

The prevalence of stunting in children under five was 20.7% (5.3% severely stunted and 15.4% stunted). Binary logistic regression analysis using SPSS version 22.0 show that mother's height as the dominant factor associated with stunting in children under five (AOR = 3.45, 95% CI: 1.12-4.67, p = 0.008). In addition, children's age (AOR = 0.250, 95% CI: 0.104-0.598, p = 0.002); balanced diet practices (AOR = 1.57, 95% CI: 0.965-2.56, p = 0.069), and building materials (AOR = 1.869, 95% CI: 0.87-4.00, p = 0.108 are also related to stunting in children under five.

Conclusions

Efforts to improve maternal nutrition need to be carried out from the period before pregnancy to the first 1000 days of life. Education on healthy home indicators, especially the use of this type of building materials for houses, needs to be done to improve sanitation as an effort to prevent stunting in children under five.

Assessment of undernutrition using the composite index of anthropometric failure (CIAF) and its determinants: A cross-sectional study in the rural area of the Bogor District in Indonesia

Background

The Composite Index of Anthropometric Failure (CIAF) can comprehensively identify undernutrition by combining several indicators of nutritional status – namely, weight-for-age, length/height-for-age and weight-for-length/height – to determine the nutritional status of children under five years of age. This study aims to assess undernutrition using the CIAF and its determinants on children under five years of age in the Bogor District, Indonesia.

Methods

A cross-sectional study was conducted during February–May 2019 among 330 mother-children pairs (with children under five), selected by systematic random sampling from four villages as undernutrition pockets in the rural area of Bogor District, Indonesia. The nutritional status of the children was assessed by measuring weight and length/height. Z-score was calculated using WHO Anthro software and was categorized based on conventional indices, including weight-for-age (WAZ), length/height-for-age (HAZ) and weight-for-length/height (WHZ). The CIAF is measured based on a combination of conventional index measurements. In addition, mothers’ and childrens’ characteristics and clean living behaviour are assessed via structured questionnaires. Environmental sanitation is assessed using the environment meter. Binary logistic regression analysis with SPSS version 22.0 is used to analyse the dominant factors associated with undernutrition.

Results

Among children under five, 42.1% experienced anthropometric failure (overall prevalence of undernutrition based on the CIAF), 2.4% experienced wasting only, 5.8% were classified as both wasting and underweight, 2.1% as wasting, underweight and stunting, 16.4% as underweight and stunting, 11.5% as stunting only, and 3.9% as underweight only. Assessment of nutritional status using a conventional anthropometric index shows that respective prevalences of underweight, stunted and wasted were 27.8, 29.7, and 10.6%. The mother’s height is the most dominant factor associated with anthropometric failure [p = 0.008; AOR = 1.95; 95% CI: 2.19–3.19]. The most dominant factors associated with the conventional undernutrition indices of underweight, stunted and wasted are, respectively, family income [p = 0.018; AOR = 5.44; 95% CI: 1.34–22.11], mother’s height [p = < 0.001; AOR = 3.29; 95% CI:1.83–5.91] and child’s age [p = 0.013; AOR = 2.59; 95% CI: 1.22–5.47].

Conclusion

Nearly half of children under five experience anthropometric failure. Specific nutrition improvement interventions and specific nutrition interventions during pregnancy and lactation are needed, especially for malnourished mothers, to prevent malnutrition in infant.

Associations between PM2.5 exposure and infant growth: A mediation analysis of oral microbiota

BACKGROUND

Previous studies have linked growth retardation with ambient fine particulate matter (PM2.5) exposure. However, few studies explored such association from the perspective of microbiota, such as oral microbiota. We aimed to identify the potential role of oral microbiota in the links between PM2.5 exposure and infant growth.

METHODS

Baseline information of 335 recruited mother-child pairs was collected by structured questionnaires. Growth indicators (weight, length) of one-year-old infants were abstracted from medical records when they had physical examination and corresponding z scores were calculated. 16S rRNA gene amplicon sequencing was performed to assess oral microbiota of infants and co-abundance groups (CAGs) were further calculated. We assessed PM2.5 levels by inverse distance weighting (IDW). Generalized linear regression and mediation analysis were performed to determine associations between PM2.5 exposure, oral microbiota and growth indicators.

RESULTS

Per 10 μg m-3 increment of PM2.5 in the period of 10th month-examination was associated with decreased length z score (β = -1.97, 95%CI: -3.83, -0.11). Oral microbiota correlated with weight z score and body mass index (BMI) z score was identified by Spearman correlation analysis. CAG4 was statistically associated with increased weight z score (β = 3.40, 95%CI: 0.29, 6.51) and BMI z score (β = 5.44, 95%CI: 1.00, 9.87). Several bacteria in the level of genus and CAG associated with PM2.5 exposure were additionally identified (P < 0.05). Mediation analysis revealed that PM2.5 in the period of birth-3rd month impacted the z scores of weight and BMI by altering relative abundance of Megasphaera (P < 0.05).

CONCLUSION

PM2.5 exposure from 10th to 12th month after birth could retard infant linear growth. PM2.5 might impact oral microbiota of one-year-old infants. Growth-related bacteria and CAGs were identified. Megasphaera might function as mediator between PM2.5 exposure during birth-3rd month and infant z scores of weight and BMI.

A Low-Cost, Easy-to-Assemble Device to Prevent Infant Hyperthermia under Conditions of High Thermal Stress

High ambient temperature and humidity greatly increase the risk of hyperthermia and mortality, particularly in infants, who are especially prone to dehydration. World areas at high risk of heat stress include many of the low- and middle-income countries (LMICs) where most of their inhabitants have no access to air conditioning. This study aimed to design, evaluate, and test a novel low-cost and easy-to-assemble device aimed at preventing the risk of infant hyperthermia in LMICs. The device is based on optimizing negative heat transfer from a small amount of ice and transferring it directly to the infant by airflow of refrigerated air. As a proof of concept, a device was assembled mainly using recycled materials, and its performance was assessed under laboratory-controlled conditions in a climatic chamber mimicking realistic stress conditions of high temperature and humidity. The device, which can be assembled by any layperson using easily available materials, provided sufficient refrigerating capacity for several hours from just 1–2 kg of ice obtained from a domestic freezer. Thus, application of this novel device may serve to attenuate the adverse effects of heat stress in infants, particularly in the context of the evolving climatic change trends.

One planet one health: What about the kids?

Humans in their increasing numbers and wealth are changing ecosystems through accelerated consumption of food, natural resources and energy which continue to cause significant damage to the planet. Using 'stunting in children' as a case study, we show how the traditional siloed (specialist) approaches have failed to reduce stunting world-wide. Despite significant effort, traditional approaches fail to appreciate the interconnectedness of the multiple factors that underpin stunting. We will not improve the lives of the millions of children living in poverty by doing the same things we have always done, rather we need to adopt approaches that recognise the interconnectedness of all the component parts and apply One Health methods designed to solve these intractable problems.

High efficacy of microbial larvicides for malaria vectors control in the city of Yaounde Cameroon following a cluster randomized trial

The rapid expansion of insecticide resistance and outdoor malaria transmission are affecting the efficacy of current malaria control measures. In urban settings, where malaria transmission is focal and breeding habitats are few, fixed and findable, the addition of anti-larval control measures could be efficient for malaria vector control. But field evidences for this approach remains scarce. Here we provide findings of a randomized-control larviciding trial conducted in the city of Yaoundé that support the efficacy of this approach. A two arms random control trial design including 26 clusters of 2 to 4 km2 each (13 clusters in the intervention area and 13 in the non-intervention area) was used to assess larviciding efficacy. The microbial larvicide VectoMax combining Bacillus thuringiensis var israelensis (Bti) and Bacillus sphaericus in a single granule was applied every 2 weeks in all standing water collection points. The anopheline density collected using CDC light traps was used as the primary outcome, secondary outcomes included the entomological inoculation rate, breeding habitats with anopheline larvae, and larval density. Baseline entomological data collection was conducted for 17 months from March 2017 to July 2018 and the intervention lasted 26 months from September 2018 to November 2020. The intervention was associated with a reduction of 68% of adult anopheline biting density and of 79% of the entomological inoculation rate (OR 0.21; 95% CI 0.14-0.30, P < 0.0001). A reduction of 68.27% was recorded for indoor biting anophelines and 57.74% for outdoor biting anophelines. No impact on the composition of anopheline species was recorded. A reduction of over 35% of adult Culex biting densities was recorded. The study indicated high efficacy of larviciding for reducing malaria transmission intensity in the city of Yaoundé. Larviciding could be part of an integrated control approach for controlling malaria vectors and other mosquito species in the urban environment.

Mapping Geographical Differences and Examining the Determinants of Childhood Stunting in Ethiopia: A Bayesian Geostatistical Analysis

Understanding the specific geographical distribution of stunting is essential for planning and implementing targeted public health interventions in high-burdened countries. This study investigated geographical variations in the prevalence of stunting sub-nationally, and the determinants of stunting among children under 5 years of age in Ethiopia. We used the 2016 Ethiopia Demographic and Health Survey (EDHS) dataset for children aged 0–59 months with valid anthropometric measurements and geographic coordinates (n = 9089). We modelled the prevalence of stunting and its determinants using Bayesian geospatially explicit regression models. The prevalence of stunting among children under five years was 36.3% (95% credible interval (CrI); 22.6%, 51.4%) in Ethiopia, with wide variations sub-nationally and by age group. The prevalence of childhood stunting ranged from 56.6% (37.4–74.6%) in the Mekelle Special zone of the Tigray region to 25.5% (10.5–48.9%) in the Sheka zone of the Southern Nations, Nationalities and Peoples region. Factors associated with a reduced likelihood of stunting in Ethiopia included non-receipt of breastmilk, mother’s BMI (overweight/obese), employment status (employed), and higher household wealth, while the enablers were residence in the “arid” geographic areas, small birth size of the child, and mother’s BMI (underweight). The prevalence and determinants of stunting varied across Ethiopia. Efforts to reduce the burden of childhood stunting should consider geographical heterogeneity and modifiable risk factors.

A Systematic Review and Appraisal of Epidemiological Studies on Household Fuel Use and Its Health Effects Using Demographic and Health Surveys

The domestic combustion of polluting fuels is associated with an estimated 3 million premature deaths each year and contributes to climate change. In many low- and middle-income countries (LMICs), valid and representative estimates of people exposed to household air pollution (HAP) are scarce. The Demographic and Health Survey (DHS) is an important and consistent source of data on household fuel use for cooking and has facilitated studies of health effects. However, the body of research based on DHS data has not been systematically identified, nor its strengths and limitations critically assessed as a whole. We aimed to systematically review epidemiological studies using DHS data that considered cooking fuel type as the main exposure, including the assessment of the extent and key drivers of bias. Following PRISMA guidelines, we searched PubMed, Web of Science, Scopus and the DHS publication portal. We assessed the quality and risk of bias (RoB) of studies using a novel tool. Of 2748 records remaining after removing duplicates, 63 were read in full. A total of 45 out of 63 studies were included in our review, spanning 11 different health outcomes and representing 50 unique analyses. In total, 41 of 45 (91%) studies analysed health outcomes in children <5 years of age, including respiratory infections (n = 17), death (all-cause) (n = 14), low birthweight (n = 5), stunting and anaemia (n = 5). Inconsistencies were observed between studies in how cooking fuels were classified into relatively high- and low-polluting. Overall, 36/50 (80%) studies reported statistically significant adverse associations between polluting fuels and health outcomes. In total, 18/50 (36%) of the analyses were scored as having moderate RoB, while 16/50 (32%) analyses were scored as having serious or critical RoB. Although HAP exposure assessment is not the main focus of the DHS, it is the main, often only, source of information in many LMICs. An appreciable proportion of studies using it to analyse the association between cooking fuel use and health have potential for high RoB, mostly related to confounder control, exposure assessment and misclassification, and outcome ascertainment. Based on our findings, we provide some suggestions for ways in which revising the information collected by the DHS could make it even more amenable to studies of household fuel use and health, and reduce the RoB, without being onerous to collect and analyse.

Recommendations for building out mosquito-transmitted diseases in sub-Saharan Africa: the DELIVER mnemonic

In sub-Saharan Africa, most transmission of mosquito-transmitted diseases, such as malaria or dengue, occurs within or around houses. Preventing mosquito house entry and reducing mosquito production around the home would help reduce the transmission of these diseases. Based on recent research, we make key recommendations for reducing the threat of mosquito-transmitted diseases through changes to the built environment. The mnemonic, DELIVER, recommends the following best practices: (i) Doors should be screened, self-closing and without surrounding gaps; (ii) Eaves, the space between the wall and roof, should be closed or screened; (iii) houses should be Lifted above the ground; (iv) Insecticide-treated nets should be used when sleeping in houses at night; (v) houses should be Ventilated, with at least two large-screened windows to facilitate airflow; (vi) Environmental management should be conducted regularly inside and around the home; and (vii) Roofs should be solid, rather than thatch. DELIVER is a package of interventions to be used in combination for maximum impact. Simple changes to the built environment will reduce exposure to mosquito-transmitted diseases and help keep regions free from these diseases after elimination. This article is part of the theme issue 'Novel control strategies for mosquito-borne diseases'.

Reducing the Carbon Footprint of Academic Conferences: The Example of the American Society of Tropical Medicine and Hygiene

We calculated carbon emissions associated with air travel of 4,834 participants at the 2019 annual conference of the American Society of Tropical Medicine and Hygiene (ASTMH). Together, participants traveled a total of 27.7 million miles or 44.6 million kilometers. This equates to 58 return trips to the moon. Estimated carbon dioxide equivalent (CO₂e) emissions were 8,646 metric tons or the total weekly carbon footprint of approximately 9,366 average American households. These emissions contribute to climate change and thus may exacerbate many of the global diseases that conference attendees seek to combat. Options to reduce conference travel-associated emissions include 1) alternating in-person and online conferences, 2) offering a hybrid in-person/online conference, and 3) decentralizing the conference with multiple conference venues. Decentralized ASTMH conferences may allow for up to 64% reduction in travel distance and 58% reduction in CO₂e emissions. Given the urgency of the climate crisis and the clear association between global warming and global health, ways to reduce carbon emissions should be considered.