Background:
Detailed dietary intake data in low-income populations are needed for research and program evaluation. However, collection of such data by paper-based 24-hour recall imposes substantial ...demands for staff time and expertise, training, materials, and data entry.
Objective:
To describe our development and use of a tablet-based 24-hour recall tool for conducting dietary intake surveys in remote settings.
Methods:
We designed a 24-hour recall tool using Open Data Kit software on an Android tablet platform. The tool contains a list of local foods, questions on portion size, cooking method, ingredients, and food source and prompts to guide interviewers. We used this tool to interview caregivers on dietary intakes of children participating in an efficacy trial of provitamin A-biofortified maize conducted in Mkushi, a rural district in central Zambia. Participants were children aged 4 to 8 years not yet enrolled in school (n = 938). Dietary intake data were converted to nutrient intakes using local food composition and recipe tables.
Results:
We developed a tablet-based 24-hour recall tool and used it to collect dietary data among 928 children. The majority of foods consumed were maize, leafy vegetable, or small fish dishes. Median daily energy intake was 6416 kJ (1469 kcal).
Conclusions:
Food and nutrient intakes assessed using the tablet-based tool were consistent with those reported in prior research. The tool was easily used by interviewers without prior nutrition training or computing experience. Challenges remain to improve programming, but the tool is an innovation that enables efficient collection of 24-hour recall data in remote settings.
Inflammation-induced hyporetinolemia (IIH), a reduction in serum retinol (SR) during inflammation, may bias population estimates of vitamin A deficiency (VAD). The optimal adjustment for IIH depends ...on the type and extent of inflammation. In rural Zambian children (4–8 years, N = 886), we compared three models for defining inflammation: α-1-acid glycoprotein (AGP) only (inflammation present if > 1 g/L or normal if otherwise), C-reactive protein (CRP) only (moderate inflammation, 5–15 mg/L; high inflammation, > 15 mg/L; or normal if otherwise) and a combined model using both AGP and CRP to delineate stages of infectious episode. Models were compared with respect to 1) the variance in SR explained and 2) comparability of inflammation-adjusted VAD estimated in low and high malaria seasons. Linear regression was used to estimate the variance in SR explained by each model and in estimating the adjustment factors used in generating adjusted VAD (retinol < 0.7 μmol/L). The variance in SR explained were 2% (AGP-only), 11% (CRP-only), and 11% (AGP–CRP) in the low malaria season; and 2% (AGP-only), 15% (CRP-only), and 12% (AGP–CRP) in the high malaria season. Adjusted VAD estimates in the low and high malaria seasons differed significantly for the AGP (8.2 versus 13.1%) and combined (5.5 versus 9.1%) models but not the CRP-only model (6.1 versus 6.3%). In the multivariate regression, a decline in SR was observed with rising CRP (but not AGP), in both malaria seasons (slope = −0.06; P < 0.001). In this malaria endemic setting, CRP alone, as opposed to CRP and AGP, emerged as the most appropriate model for quantifying IIH.
Background
Vitamin A deficiency is a major public health nutrition problem, affecting an estimated 190 million preschool-aged children and 19 million pregnant and lactating women globally, and 83 ...million adolescents in Southeast Asia alone. Its consequences (disorders) include xerophthalmia (the leading cause of early childhood blindness), increased severity of infection, anemia, and death. Because vitamin A deficiency is largely due to chronic dietary insufficiency of preformed vitamin A and proactive carotenoids, food fortification can offer an effective approach to prevention.
Objective
To provide guidance on fortifying wheat and maize flour milled in industrial rollers for national fortification programs in countries where vitamin A deficiency is considered a public health problem.
Methods
Critical review of the literature on the dietary gap in vitamin A intake and levels of wheat flour intake among risk groups as a basis for determining vitamin A fortificant levels. Additional review of efficacy evidence, safety and cost considerations, and country experiences related to wheat-flour fortification with vitamin A.
Results
Mill-rolled wheat flour is a technically fortifiable, centrally processed food vehicle that, where routinely and adequately consumed by target groups, should be considered a candidate for fortification. Vitamin A can be stable in flour under typical, ambient conditions, with processing losses estimated at approximately 30%, depending on source and premix conditions.
Conclusions
Factors to guide a decision to fortify flour with vitamin A include the extent of deficiency, availability of other food vehicle options, the centrality of milling, market reach and population intake distributions of the flour products, the dietary vitamin A intake required, and associated costs. Large gaps persist in knowledge of these factors, which are needed to enable evidence-based fortification in most countries, leaving most decisions to fortify guided by assumptions. Where flour can and should be fortified, guidelines are given for providing nearly 25% of the Recommended Dietary Allowance for vitamin A to vulnerable groups consuming varying ranges of flour products. The costs will vary according to the level of fortification.
Public policy requires public support, which in turn implies a need to enable the public not just to understand policy but also to be engaged in its development. Where complex science and technology ...issues are involved in policy making, this takes time, so it is important to identify emerging issues of this type and prepare engagement plans. In our horizon scanning exercise, we used a modified Delphi technique. A wide group of people with interests in the science and policy interface (drawn from policy makers, policy adviser, practitioners, the private sector and academics) elicited a long list of emergent policy issues in which science and technology would feature strongly and which would also necessitate public engagement as policies are developed. This was then refined to a short list of top priorities for policy makers. Thirty issues were identified within broad areas of business and technology; energy and environment; government, politics and education; health, healthcare, population and aging; information, communication, infrastructure and transport; and public safety and national security.
•Barbados green monkeys (Chlorocebus sabaeus) have been isolated from their African predators (e.g., leopards) for over 350 years.•When presented with images of leopards or non-predatory African ...buffalos, the leopard elicited greater avoidance, more alarm calls, and appropriate anti-predator behavior (escape into trees).•Stimuli bearing dark rosettes on tan fur were avoided by the monkeys. The presence of forward-facing predator eyes (versus side-facing prey eyes) on stimuli did not reliably deter approach.•Predator recognition and anti-predator behavior in green monkeys appears to be at least partially mediated by genetic factors.
Ability to recognize and differentiate between predators and non-predators is a crucial component of successful anti-predator behavior. While there is evidence that both genetic and experiential mechanisms mediate anti-predator behaviors in various animal species, it is unknown to what extent each of these two mechanisms are utilized by the green monkey (Chlorocebus sabaeus). Green monkeys on the West Indies island of Barbados offer a unique opportunity to investigate the underpinnings of anti-predator behaviors in a species that has been isolated from ancestral predators for over 350 years. In the first experiment, monkeys in two free-ranging troops were presented with photographs of an ancestral predator (leopard, Panthera pardus) and a non-predator (African Buffalo, Syncerus caffer). Relative to non-predator stimuli, images of a leopard elicited less approach, more alarm calls, and more escape responses. Subsequent experiments were conducted to determine whether the monkeys were responding to a leopard-specific feature (spotted fur) or a general predator feature (forward facing eyes). The monkeys showed similar approach to images of an unfamiliar non-predator regardless of whether the image had forward facing predator eyes or side facing non-predator eyes. However, once near the images, the monkeys were less likely to reach for peanuts near the predator eyes than the non-predator eyes. The monkeys avoided an image of spotted leopard fur but approached the same image of fur when the dark spots had been removed. Taken together, the results suggest that green monkey anti-predator behavior is at least partially mediated by genetic factors.
Aberrant dark adaptation is common to many ocular diseases and pathophysiological conditions, including vitamin A deficiency, cardiopulmonary diseases, and hypoxia. Scotopic vision and pupillary ...responsiveness have typically been measured using subjective, time-consuming methods. Existing techniques are particularly challenging for use in developing country settings, where vitamin A deficiency remains a major public health problem. Our aim was design a compact, low cost, and easily operated device to assess dark adaptation in the field.
The Portable Field Dark Adaptometer (PFDA) incorporates a digital camera, a retinal bleaching flash, and a Ganzfeld light source inside a pair of light-obscuring goggles. After a ~10 min period of dark adaption, the infrared camera digitally records afferent pupillary responses to graded light stimuli (-2.9 to 0.1 log cd/m(2)). We tested this device in a variety of field settings to assess: a) ease of use and b) whether test data could clearly and accurately depict the well-known dose-response relationship between light intensity and pupil contraction. A total of 822 videos were collected. We used an open source video analysis software to measure pupil size in pixel units. Pupillary responsiveness was expressed as the percent change in pupil size from pre- to post-light exposure. Box plots, t test, and multi-level mixed effects linear regression modeling were used to characterize the relationship between light intensity and pupillary response.
The PFDA was employed with only minor technical challenges in Bangladesh, Kenya, Zambia, and Peru. Our data show a clear linear increase in pupillary constriction with increasing log light intensity. Light intensity was a strong predictor of pupillary response, regardless of baseline pupil size.
The consistent physiological response demonstrated here supports the use of the PFDA as a reliable tool to measure dark adaptation. As a next step, PFDA measurements will be validated against biochemical indicators of vitamin A status and hypoxemia. Ultimately, this new technology may provide a novel approach for nutritional assessment, with potential clinical applications.
Linear growth during three distinct stages of life determines attained stature in adulthood: namely, in utero, early postnatal life, and puberty and the adolescent period. Individual host factors, ...genetics, and the environment, including nutrition, influence attained human stature. Each period of physical growth has its specific biological and environmental considerations. Recent epidemiologic investigations reveal a strong influence of prenatal factors on linear size at birth that in turn influence the postnatal growth trajectory. Although average population height changes have been documented in high-income regions, stature as a complex human trait is not well understood or easily modified. This review summarizes the biology of linear growth and its major drivers including nutrition from a life-course perspective, the genetics of programmed growth patterns or height, and gene-environment interactions that determine human stature in toto over the life span. Implications for public health interventions and knowledge gaps are discussed.
Approximately five million children die each year from preventable causes, including respiratory infections, diarrhea, and malaria. Roughly half of those deaths are attributable to undernutrition, ...including micronutrient deficiencies (MNDs). The influence of infection on micronutrient status is well established: The inflammatory response to pathogens triggers anorexia, while pathogens and the immune response can both alter nutrient absorption and cause nutrient losses. We review the roles of vitamin A, vitamin D, iron, zinc, and selenium in the immune system, which act in the regulation of molecular- or cellular-level host defenses, directly affecting pathogens or protecting against oxidative stress or inflammation. We further summarize high-quality evidence regarding the synergistic or antagonistic interactions between MNDs, pathogens, and morbidity or mortality relevant to child health in low- and middle-income countries. We conclude with a discussion of gaps in the literature and future directions for multidisciplinary research on the interactions of MNDs, infection, and inflammation.
A quarter of century has passed since FRI published its first comprehensive review on vitamin A deficiency (VAD) and its prevention. At the time, the major impetus to prevent VAD was to reduce ...xerophthalmia in preschool children. Today, we have a broader understanding of the public health implications of VAD, with disorders including xerophthalmia, mortality, severe infection, and anemia in preschool children and pregnant women. While deficiency affects most developing countries, nearly half of all deficient children and women live in Southern Asia. Prevention has made substantial strides. High potency vitamin A supplementation (with 200,000 IU) remains a prophylactic mainstay, delivered through fixed facilities, enhanced outreach activities, and national child health day campaigns twice annually. Surprisingly, the costs of semi-annual delivery of vitamin A have changed little over the years, with new cost estimates remaining comparable to earlier figures of US ∼$0.50 per child per year. Emerging is the potential to reduce infant mortality by ∼20% in Southern Asia by giving a single, oral, 50,000 IU dose of vitamin A to newborns. While ∼500 million vitamin A capsules are routinely distributed worldwide each year to achieve effective control, progress has been slower with efforts to improve diet on a purposeful global public health scale. Future advances through effective dietary diversification and various means of food fortification will be required before periodic supplementation can be phased down as a major population strategy for controlling vitamin A deficiency.
PDF
