El Niño adversely affected childhood stature and lean mass in northern Peru

Maternal preconceptional and prenatal exposure to El Niño Southern Oscillation levels and child mortality: a multi-country study

El Niño Southern Oscillation (ENSO) has been shown to relate to the epidemiology of childhood infectious diseases, but evidence for whether they increase child deaths is limited. Here, we investigate the impact of mothers' ENSO exposure during and prior to delivery on child mortality by constructing a retrospective cohort study in 38 low- and middle-income countries. We find that high levels of ENSO indices cumulated over 0-12 lagged months before delivery are associated with significant increases in risks of under-five mortality; with the hazard ratio ranging from 1.33 (95% confidence interval [CI], 1.26, 1.40) to 1.89 (95% CI, 1.78, 2.00). Child mortality risks are particularly related to maternal exposure to El Niño-like conditions in the 0th-1st and 6th-12th lagged months. The El Niño effects are larger in rural populations and those with unsafe sources of drinking water and less education. Thus, preventive interventions are particularly warranted for the socio-economically disadvantaged.

Impact of floods on undernutrition among children under five years of age in low- and middle-income countries: a systematic review

BACKGROUND

Weather and climate-related disasters, including floods, impact undernutrition through multiple pathways, including food security, inadequate child care practices, and water and sanitation. This review aimed to provide systematic evidence of the impact of floods on undernutrition in children under five years of age in Low and Middle-income countries (LMICs).

METHODS

We searched PubMed, Web of Science, Embase, MEDLINE, CINAHL and Scopus for peer-reviewed articles. Popline, WHO Library database (WHOLIS), the International Disaster database (EM-DAT), Food and Agriculture Organisation (FAO), UNICEF and Eldis were searched for grey literature articles. Database searches were first conducted in 2016 and updated in 2020. We included English language articles that reported the effect of floods on undernutrition outcomes in children under 5 years of age in LMICs, without limitation to study design and year of publication. The quality of selected studies was assessed using the National Institutes of Health (NIH) tool for Observational Cohort and Cross-Sectional Studies.

RESULTS

Of the 5701 articles identified, 14 met our inclusion criteria. The review noted stunting as the most frequently reported significant form of undernutrition in flood-affected areas. Severe and recurrent floods showed the greatest impact on undernutrition. Due to weak and limited evidence, the study is inconclusive on the most significant forms within the short-term and intermediate periods following floods. On the other hand, stunting was noted as the most frequently reported significant form of undernutrition in the long-term period following floods. There was generally little evidence of the effect of floods on micronutrient deficiencies. Factors associated with child undernutrition in the flood-affected areas included age, gender, diarrhoea, maternal and paternal education, maternal age, household size, land ownership and socioeconomic status. Overall, the quality of the evidence was fairly weak, with the main challenge lying in the inability of the studies to establish causal pathways for the observed effects.

CONCLUSIONS

The review suggests clear plans and strategies for preventing and reducing the long-term impact of floods on undernutrition in children under five years. Future research utilising long-term prospective data is indispensable to provide more robust evidence to guide better prevention measures, response decisions and interventions.

External validation of a prediction model for estimating fat mass in children and adolescents in 19 countries: individual participant data meta-analysis

OBJECTIVE

To evaluate the performance of a UK based prediction model for estimating fat-free mass (and indirectly fat mass) in children and adolescents in non-UK settings.

DESIGN

Individual participant data meta-analysis.

SETTING

19 countries.

PARTICIPANTS

5693 children and adolescents (49.7% boys) aged 4 to 15 years with complete data on the predictors included in the UK based model (weight, height, age, sex, and ethnicity) and on the independently assessed outcome measure (fat-free mass determined by deuterium dilution assessment).

MAIN OUTCOME MEASURES

The outcome of the UK based prediction model was natural log transformed fat-free mass (lnFFM). Predictive performance statistics of R², calibration slope, calibration-in-the-large, and root mean square error were assessed in each of the 19 countries and then pooled through random effects meta-analysis. Calibration plots were also derived for each country, including flexible calibration curves.

RESULTS

The model showed good predictive ability in non-UK populations of children and adolescents, providing R² values of >75% in all countries and >90% in 11 of the 19 countries, and with good calibration (ie, agreement) of observed and predicted values. Root mean square error values (on fat-free mass scale) were <4 kg in 17 of the 19 settings. Pooled values (95% confidence intervals) of R², calibration slope, and calibration-in-the-large were 88.7% (85.9% to 91.4%), 0.98 (0.97 to 1.00), and 0.01 (-0.02 to 0.04), respectively. Heterogeneity was evident in the R² and calibration-in-the-large values across settings, but not in the calibration slope. Model performance did not vary markedly between boys and girls, age, ethnicity, and national income groups. To further improve the accuracy of the predictions, the model equation was recalibrated for the intercept in each setting so that country specific equations are available for future use.

CONCLUSION

The UK based prediction model, which is based on readily available measures, provides predictions of childhood fat-free mass, and hence fat mass, in a range of non-UK settings that explain a large proportion of the variability in observed fat-free mass, and exhibit good calibration performance, especially after recalibration of the intercept for each population. The model demonstrates good generalisability in both low-middle income and high income populations of healthy children and adolescents aged 4-15 years.

Maternal internal migration and child growth and nutritional health in Peru: an analysis of the demographic and health surveys from 1991 to 2017

BACKGROUND

Peru has historically experienced high rural-to-urban migration. Despite large reductions in undernutrition, overweight is increasing. Elsewhere, internal migration has been associated with differences in children's growth and nutritional health. We investigated how child growth and nutritional status in Peru varied over time and in association with maternal internal migration.

METHODS

Using data from Demographic & Health Surveys from 1991 to 2017, we assessed trends in child growth (height-for-age [HAZ], weight-for-age [WAZ], weight-for-height [WHZ] z scores) and nutritional health (stunting, underweight, overweight) by maternal adult internal migration (urban [UNM] or rural non-migrant [RNM], or urban-urban [UUM], rural-urban [RUM], rural-rural [RRM], or urban-rural migrant [URM]). Using 2017 data, we ran regression analyses, adjusting for confounders, to investigate associations of maternal migration with child outcomes and the maternal and child double burden of malnutrition. We further stratified by timing of migration, child timing of birth and, for urban residents, type of area of residence. Results are given as adjusted predictive margins (mean z score or %) and associated regression p-values [p].

RESULTS

In 1991-2017, child growth improved, and undernutrition decreased, but large differences by maternal migration persisted. In 2017, within urban areas, being the child of a migrant woman was associated with lower WHZ (UUM = 0.6/RUM = 0.5 vs UNM = 0.7; p = 0.009 and p < 0.001 respectively) and overweight prevalence ((RUM 7% vs UNM = 11% [p = 0.002]). Results however varied both by child timing of birth (birth after migration meant greater overweight prevalence) and type of area of residence (better linear growth in children of migrants [vs non-migrants] in capital/large cities and towns but not small cities). In rural areas, compared to RNM, children of URM had higher HAZ (- 1.0 vs - 1.2; p < 0.001) and WAZ (- 0.3 vs - 0.4; p = 0.001) and lower stunting (14% vs 21%; [p < 0.001]). There were no differences by timing of birth in rural children, nor by time since migration across all children. The mother and child double burden of malnutrition was higher in rural than urban areas but no differences were found by maternal internal migration.

CONCLUSIONS

Migration creates a unique profile of child nutritional health that is not explained by maternal ethnic and early life factors, but which varies depending on the pathway of migration, the child timing of birth in relation to migration and, for urban dwellers, the size of the place of destination. Interventions to improve child nutritional health should take into consideration maternal health and migration history.

La Niña weather impacts dietary patterns and dietary diversity among children in the Peruvian Amazon

Objective:

In 2011–2012, severe El Niño Southern Oscillation (ENSO) conditions (La Niña) led to massive flooding and temporarily displacement in the Peruvian Amazon. Our aims were to examine the impact of this ENSO exposure on child diets, in particular: (1) frequency of food consumption patterns, (2) the amount of food consumed (g/d), (3) dietary diversity (DD), (4) consumption of donated foods, among children aged 9–36 months living in the outskirts of City of Iquitos in the Amazonian Peru.

Design:

This was a longitudinal study that used quantitative 24-h recall dietary data collection from children aged 9–36 months from 2010 to 2014 as part of the MAL-ED birth cohort study.

Setting:

Iquitos, Loreto, Peru.

Participants:

Two hundred and fifty-two mother–child dyads.

Results:

The frequency of grains, rice, dairy and sugar in meals reduced by 5–7 %, while the frequency of plantain in meals increased by 24 % after adjusting for covariates. ENSO exposure reduced girl’s intake of plantains and sugar. Despite seasonal fluctuations in the availability of fruits, vegetables and fish, DD remained constant across seasons and as children aged. However, DD was significantly reduced under moderate La Niña conditions by 0·32 (P < 0·05) food groups. Adaptive social strategies such as consumption of donated foods were significantly higher among households with girls.

Conclusions:

This is the first empirical study to show differential effect of the ENSO on the dietary patterns of children, highlighting differences by gender. Public health nutrition programmes should be climate- and gender-sensitive in their efforts to safeguard the diets of vulnerable populations.

Beyond Bergmann's rule: Global variability in human body composition is associated with annual average precipitation and annual temperature volatility

OBJECTIVES

Human populations exhibit substantial geographical variability in body size and shape. However, the ecological stresses underlying this morphological variability remain poorly understood. The prevailing evolutionary explanation, "Bergmann's rule" assumes that morphological variability represents an adaptive response to average thermal conditions. We hypothesized that other climate factors-annual average precipitation, a marker of ecological productivity and inter-annual temperature volatility, a marker of infectious disease spikes-may also contribute to variability in body composition.

MATERIALS AND METHODS

We explored this hypothesis by examining associations between these climate factors and geographic variability in body composition across 133 male and 105 female populations from nonindustrialized settings. We used monthly climate data over 113 years (1901-2013) to develop new climate indices for all worldwide land areas. We stratified our analyses by hot/cold setting (>/<20°C).

RESULTS

In hot environments, lean mass increased as predicted in association with ecological productivity, and decreased in association with ecological volatility. Conversely, levels of body fat increased in association with temperature volatility and precipitation. However, in cold settings, equivalent associations were only partially consistent with our hypotheses, and there was suggestive evidence of sex differences in these associations.

DISCUSSION

Beyond associations with mean annual temperature predicted by Bergmann's rule, variability in human body composition is also associated with mean annual temperature and inter-annual temperature volatility, with these associations further differing between hot and cold settings. Collectively, our results suggest that associations of human body composition with climate are complex for both physique (fat-free mass) and energy stores (adiposity).

Obesity is not just elevated adiposity, it is also a state of metabolic perturbation

Nettle et al. miss the crucial difference between adaptive models of storing energy and explanations for the pathological metabolic state of obesity. I suggest that the association of food insecurity with obesity in women from industrialized settings is most likely due to reverse causation: Poverty reduces agency to resist obesogenic foods, and this scenario is compounded by perturbations of insulin metabolism stemming from high adiposity and lipogenic diets.

Body composition and susceptibility to type 2 diabetes: an evolutionary perspective

Type 2 diabetes is rapidly increasing in prevalence worldwide, in concert with epidemics of obesity and sedentary behavior that are themselves tracking economic development. Within this broad pattern, susceptibility to diabetes varies substantially in association with ethnicity and nutritional exposures through the life-course. An evolutionary perspective may help understand why humans are so prone to this condition in modern environments, and why this risk is unequally distributed. A simple conceptual model treats diabetes risk as the function of two interacting traits, namely 'metabolic capacity' which promotes glucose homeostasis, and 'metabolic load' which challenges glucose homoeostasis. This conceptual model helps understand how long-term and more recent trends in body composition can be considered to have shaped variability in diabetes risk. Hominin evolution appears to have continued a broader trend evident in primates, towards lower levels of muscularity. In addition, hominins developed higher levels of body fatness, especially in females in relative terms. These traits most likely evolved as part of a broader reorganization of human life history traits in response to growing levels of ecological instability, enabling both survival during tough periods and reproduction during bountiful periods. Since the emergence of Homo sapiens, populations have diverged in body composition in association with geographical setting and local ecological stresses. These long-term trends in both metabolic capacity and adiposity help explain the overall susceptibility of humans to diabetes in ways that are similar to, and exacerbated by, the effects of nutritional exposures during the life-course.

Towards sustainable partnerships in global health: the case of the CRONICAS Centre of Excellence in Chronic Diseases in Peru

Human capital requires opportunities to develop and capacity to overcome challenges, together with an enabling environment that fosters critical and disruptive innovation. Exploring such features is necessary to establish the foundation of solid long-term partnerships. In this paper we describe the experience of the CRONICAS Centre of Excellence in Chronic Diseases, based at Universidad Peruana Cayetano Heredia in Lima, Peru, as a case study for fostering meaningful and sustainable partnerships for international collaborative research. The CRONICAS Centre of Excellence in Chronic Diseases was established in 2009 with the following Mission: "We support the development of young researchers and collaboration with national and international institutions. Our motivation is to improve population's health through high quality research." The Centre's identity is embedded in its core values - generosity, innovation, integrity, and quality- and its trajectory is a result of various interactions between multiple individuals, collaborators, teams, and institutions, which together with the challenges confronted, enables us to make an objective assessment of the partnership we would like to pursue, nurture and support. We do not intend to provide a single example of a successful partnership, but in contrast, to highlight what can be translated into opportunities to be faced by research groups based in low- and middle-income countries, and how these encounters can provide a strong platform for fruitful and sustainable partnerships. In defiant contexts, partnerships require to be nurtured and sustained. Acknowledging that all partnerships are not and should not be the same, we also need to learn from the evolution of such relationships, its key successes, hurdles and failures to contribute to the promotion of a culture of global solidarity where mutual goals, mutual gains, as well as mutual responsibilities are the norm. In so doing, we will all contribute to instil a new culture where expectations, roles and interactions among individuals and their teams are horizontal, the true nature of partnerships.

Flood-Exposure is Associated with Higher Prevalence of Child Undernutrition in Rural Eastern India

BACKGROUND

Child undernutrition and flooding are highly prevalent public health issues in Asia, yet epidemiological studies investigating this association are lacking.

METHODS

To investigate to what extent floods exacerbate poor nutritional status in children and identify most vulnerable groups, we conducted a population-based survey of children aged 6-59 months inhabiting flooded and non-flooded communities of the Jagatsinghpur district, Odisha (India), one year after large floods in 2008. Anthropometric measurements on 879 children and child, parental and household level variables were collected through face-to-face interviews in September 2009. The association between flooding and the prevalence of wasting, stunting and underweight was examined using weighted multivariate logistic regression for children inhabiting communities exposed solely to floods in 2008 and those communities repeatedly flooded (2006 and 2008) controlling for parental education and other relevant variables. We examined the influence of age on this association. Propensity score matching was conducted to test the robustness of our findings.

RESULTS

The prevalence of wasting among children flooded in 2006 and 2008 was 51.6%, 41.4% in those flooded only in 2008, and 21.2% in children inhabiting non-flooded communities. Adjusting by confounders, the increased prevalence relative to non-flooded children in the exposed groups were 2.30 (adjusted prevalence ratio (aPR); 95% CI: 1.86, 2.85) and 1.94 (95% CI: 1.43, 2.63), respectively. Among repeatedly flooded communities, cases of severe wasting in children were 3.37 times more prevalent than for children inhabiting in those non-flooded (95% CI: 2.34, 4.86) and nearly twice more prevalent relative to those flooded only once. Those children younger than one year during previous floods in 2006 showed the largest difference in prevalence of wasting compared to their non-flooded counterparts (aPR: 4.01; 95% CI: 1.51, 10.63). RESULTS were robust to alternative adjusted models and in propensity score matching analyses. For similar analyses, no significant associations were found for child stunting, and more moderate effects were observed in the case of child underweight.

CONCLUSIONS

Particularly in low-resource or subsistence-farming rural settings, long-lasting nutritional response in the aftermath of floods should be seriously considered to counteract the long-term nutritional effects on children, particularly infants, and include their mothers on whom they are dependent. The systematic monitoring of nutritional status in these groups might help to tailor efficient responses in each particular context.