Sera L. Young

Conceptual framework for understanding the bidirectional links between food insecurity and HIV/AIDS

Food insecurity, which affects >1 billion people worldwide, is inextricably linked to the HIV epidemic. We present a conceptual framework of the multiple pathways through which food insecurity and HIV/AIDS may be linked at the community, household, and individual levels. Whereas the mechanisms through which HIV/AIDS can cause food insecurity have been fairly well elucidated, the ways in which food insecurity can lead to HIV are less well understood. We argue that there are nutritional, mental health, and behavioral pathways through which food insecurity leads to HIV acquisition and disease progression. Specifically, food insecurity can lead to macronutrient and micronutrient deficiencies, which can affect both vertical and horizontal transmission of HIV, and can also contribute to immunologic decline and increased morbidity and mortality among those already infected. Food insecurity can have mental health consequences, such as depression and increased drug abuse, which, in turn, contribute to HIV transmission risk and incomplete HIV viral load suppression, increased probability of AIDS-defining illness, and AIDS-related mortality among HIV-infected individuals. As a result of the inability to procure food in socially or personally acceptable ways, food insecurity also contributes to risky sexual practices and enhanced HIV transmission, as well as to antiretroviral therapy nonadherence, treatment interruptions, and missed clinic visits, which are strong determinants of worse HIV health outcomes. More research on the relative importance of each of these pathways is warranted because effective interventions to reduce food insecurity and HIV depend on a rigorous understanding of these multifaceted relationships.

What Are We Assessing When We Measure Food Security? A Compendium and Review of Current Metrics

The appropriate measurement of food security is critical for targeting food and economic aid; supporting early famine warning and global monitoring systems; evaluating nutrition, health, and development programs; and informing government policy across many sectors. This important work is complicated by the multiple approaches and tools for assessing food security. In response, we have prepared a compendium and review of food security assessment tools in which we review issues of terminology, measurement, and validation. We begin by describing the evolving definition of food security and use this discussion to frame a review of the current landscape of measurement tools available for assessing food security. We critically assess the purpose/s of these tools, the domains of food security assessed by each, the conceptualizations of food security that underpin each metric, as well as the approaches that have been used to validate these metrics. Specifically, we describe measurement tools that 1) provide national-level estimates of food security, 2) inform global monitoring and early warning systems, 3) assess household food access and acquisition, and 4) measure food consumption and utilization. After describing a number of outstanding measurement challenges that might be addressed in future research, we conclude by offering suggestions to guide the selection of appropriate food security metrics.

A Review of the Role of Food Insecurity in Adherence to Care and Treatment Among Adult and Pediatric Populations Living with HIV and AIDS

Adherence to antiretroviral therapy (ART) is critical for reducing HIV/AIDS morbidity and mortality. Food insecurity (FI) is emerging as an important barrier to adherence to care and treatment recommendations for people living with HIV (PLHIV), but this relationship has not been comprehensively examined. Therefore, we reviewed the literature to explore how FI may impact ART adherence, retention in medical care, and adherence to health care recommendations among PLHIV. We found data to support FI as a critical barrier to adherence to ART and to other health care recommendations among HIV-infected adults, HIV-infected pregnant women and their HIV-exposed infants, and child and adolescent populations of PLHIV. Associations between FI and ART non-adherence were seen in qualitative and quantitative studies. We identified a number of mechanisms to explain how food insecurity and ART non-adherence may be causally linked, including the exacerbation of hunger or ART side effects in the absence of adequate food and competing resource demands. Interventions that address FI may improve adherence to care and treatment recommendations for PLHIV.

Pica in Pregnancy: New Ideas About an Old Condition

Pica, the purposive consumption of nonfood substances, is a millennia-old nutritional enigma. Its worldwide ubiquity, prevalence among pregnant women and children, and association with both positive and negative health outcomes, especially micronutrient deficiencies, underscore the importance of understanding this behavior. Multiple proposed etiologies of pica are reviewed, including cultural expectations, psychological stress, hunger, dyspepsia, micronutrient deficiencies (Fe, Zn, and Ca), and protection against toxins and pathogens. Currently available data, although limited, best support the protection hypothesis as a cause of most types of pica, although some evidence suggests that pagophagy (ice consumption) may occur during iron deficiency. It is possible that the binding capacity of pica substances explains the association with micronutrient deficiencies; earth, starch, etc. may render micronutrients in ingesta unavailable for absorption. Increased research efforts are warranted and must be hypothesis driven, interdisciplinary, and permit the testing of multiple causal inferences.

WHY ON EARTH?: EVALUATING HYPOTHESES ABOUT THE PHYSIOLOGICAL FUNCTIONS OF HUMAN GEOPHAGY

Geophagy has been hypothesized to be an adaptive behavior, either as a means to allay nutrient deficiency or to protect against ingested pathogens and toxins. Others have proposed that geophagy is non-adaptive, occurring either to allay hunger or as an epiphenomenon of nutrient deficiencies. This paper evaluates these hypotheses using 482 published cultural-level accounts of human geophagy and 330 accounts of geophagy among 297 species of mammals, birds, and reptiles. Information was extracted from reports of human geophagy to permit statistical analysis; reports of non-human geophagy were tabulated. Human geophagy did not parallel changes in nutrient requirements, occurred most frequently among children and pregnant women and in tropical areas (where pathogen densities are highest), and was associated with ingestion of toxic substances and gastrointestinal distress. Earth ingested by humans was craved and carefully selected and prepared; it had high clay content, but few bioavailable mineral nutrients. In primates, geophagy was associated with both protection from toxins and obtaining nutrients, whereas in other vertebrates it was associated mainly with obtaining nutrients. Our results indicate that human geophagy is best explained as providing protection from dietary chemicals, parasites, and pathogens, whereas animal geophagy may involve both micronutrient acquisition and protection.

Association of Pica with Anemia and Gastrointestinal Distress among Pregnant Women in Zanzibar, Tanzania

The etiology of pica, the purposive consumption of non-food substances, is not understood, despite its ubiquity among gravidae. We examined correlates of pica in a representative obstetric population (n = 2,368) on Pemba Island, Zanzibar, Tanzania to examine proposed etiologies. Cross-sectional data were collected on socioeconomic characteristics, food intake, geophagy (earth consumption), amylophagy (raw starch consumption), anthropometry, iron status, parasitic burden, and gastrointestinal morbidities. Amylophagy was reported by 36.3%, geophagy by 5.2%, and any pica by 40.1%. There was a strong additive relationship of geophagy and amylophagy with lower hemoglobin (Hb) concentration and iron deficiency anemia. By multivariate logistic regression, any pica was associated with Hb level (odds ratio [OR] = 0.76, 95% confidence interval [CI] = 0.72-0.81), nausea (OR = 1.45, 95% CI = 1.20-1.73), and abdominal pain (OR = 1.22, 95% CI = 1.01-1.48). These striking results indicate that the nature of the relationship between pica, pregnancy, gastrointestinal distress, and iron deficiency anemia merits further investigation.

Social determinants, lived experiences, and consequences of household food insecurity among persons living with HIV/AIDS on the shore of Lake Victoria, Kenya

Food insecurity is a considerable challenge in sub-Saharan Africa, disproportionately affecting persons living with HIV/AIDS. This study investigates the lived experience, determinants, and consequences of food insecurity and hunger among individuals living with HIV/AIDS on the shore of Lake Victoria in Suba District, Kenya. Parallel mixed methods included semi-structured interviews and administration of the Household Food Insecurity Access Scale among a systematic sample of 67 persons living with HIV/AIDS (49 of whom were receiving antiretroviral therapy [ART]). All respondents were either severely (79.1%) or moderately (20.9%) food insecure; no respondents were mildly food insecure or food secure. Qualitative data and simple and multiple linear regression models indicated that significant determinants of food insecurity include increased age, a greater number of children, and not being married. A number of themes related to food insecurity and ART emerged, including: (1) an increase in hunger or appetite since initiating ART; (2) exacerbation of ART-related side effects; and (3) non-adherence to ART due to hunger, food insecurity, or agricultural work responsibilities. HIV interventions should address food insecurity and hunger, particularly among at-risk populations, to promote ART adherence and better health outcomes.

Current knowledge and future research on infant feeding in the context of HIV: Basic, clinical, behavioral, and programmatic perspectives

In 2008, between 129,000 and 194,000 of the 430,000 pediatric HIV infections worldwide were attributable to breastfeeding. Yet in many settings, the health, economic, and social consequences of not breastfeeding would have dire consequences for many more children. In the first part of this review we provide an overview of current knowledge about infant feeding in the context of HIV. Namely, we describe the benefits and risks of breastmilk, the evolution of recommended infant feeding modalities in high-income and low-income countries in the last two decades, and contextualize the recently revised guidelines for infant feeding in the context of HIV current knowledge. In the second section, we suggest areas for future research on the postnatal prevention of mother-to-child transmission of HIV (PMTCT) in developing and industrialized countries. We suggest two shifts in perspective. The first is to evaluate PMTCT interventions more holistically, to include the psychosocial and economic consequences as well as the biomedical ones. The second shift in perspective should be one that contextualizes postnatal PMTCT efforts in the cascade of maternal health services. We conclude by discussing basic, clinical, behavioral, and programmatic research questions pertaining to a number of PMTCT efforts, including extended postnatal ARV prophylaxis, exclusive breastfeeding promotion, counseling, breast milk pasteurization, breast milk banking, novel techniques for making breast milk safer, and optimal breastfeeding practices. We believe the research efforts outlined here will maximize the number of healthy, thriving, HIV-free children around the world.

Differences and commonalities in physical, chemical and mineralogical properties of Zanzibari geophagic soils.

The function of human geophagy has long been questioned. We sought to test hypotheses concerning its potential physiological effects through analysis of soils and patterns in geophagy behavior. Eleven samples of geophagic soils consumed by pregnant women on Pemba Island, Zanzibar, Tanzania, were characterized according to their color, texture, major element chemistry, trace element chemistry, bulk mineralogy, and clay mineralogy. An epidemiological study (N = 2367) and ethnographic interviews (N = 57) on Pemba yielded information about geophagic behaviors and socio-demographic and biological characteristics of those who consumed earth. The soils varied widely in color, ranging from light red to white through various shades of brown and yellow, and texture ranged from clay to sand. Major element chemistry of the soils also varied greatly; most were low in Fe and Ca. Trace elements, whether of biological or non-biological significance, were uniformly low when compared with normal ranges of mineral soils. The sole commonality among the samples is that all clay fractions were dominated by a kaolin mineral: kaolinite, halloysite, or a mixture of both. Geophagy behavior also varied greatly, with one major exception: a greater proportion of pregnant women (7.1%) and young children (4.5%) consumed earth than non-pregnant women (0.2%) or men (0%). The presence of kaolin mineral in all samples, its palliative and detoxifying properties, and the highest prevalence of geophagy among those most biologically vulnerable suggest that geophagy may be a protective behavior.

The association between malnutrition and the incidence of malaria among young HIV-infected and -uninfected Ugandan children: a prospective study.

BackgroundIn sub-Saharan Africa, malnutrition and malaria remain major causes of morbidity and mortality in young children. There are conflicting data as to whether malnutrition is associated with an increased or decreased risk of malaria. In addition, data are limited on the potential interaction between HIV infection and the association between malnutrition and the risk of malaria.MethodsA cohort of 100 HIV-unexposed, 203 HIV-exposed (HIV negative children born to HIV-infected mothers) and 48 HIV-infected children aged 6 weeks to 1 year were recruited from an area of high malaria transmission intensity in rural Uganda and followed until the age of 2.5 years. All children were provided with insecticide-treated bed nets at enrolment and daily trimethoprim-sulphamethoxazole prophylaxis (TS) was prescribed for HIV-exposed breastfeeding and HIV-infected children. Monthly routine assessments, including measurement of height and weight, were conducted at the study clinic. Nutritional outcomes including stunting (low height-for-age) and underweight (low weight-for-age), classified as mild (mean z-scores between -1 and -2 during follow-up) and moderate-severe (mean z-scores < -2 during follow-up) were considered. Malaria was diagnosed when a child presented with fever and a positive blood smear. The incidence of malaria was compared using negative binomial regression controlling for potential confounders with measures of association expressed as an incidence rate ratio (IRR).ResultsThe overall incidence of malaria was 3.64 cases per person year. Mild stunting (IRR = 1.24, 95% CI 1.06-1.46, p = 0.008) and moderate-severe stunting (IRR = 1.24, 95% CI 1.03-1.48, p = 0.02) were associated with a similarly increased incidence of malaria compared to non-stunted children. Being mildly underweight (IRR = 1.09, 95% CI 0.95-1.25, p = 0.24) and moderate-severe underweight (IRR = 1.12, 95% CI 0.86-1.46, p = 0.39) were not associated with a significant difference in the incidence of malaria compared to children who were not underweight. There were no significant interactions between HIV-infected, HIV-exposed children taking TS and the associations between malnutrition and the incidence of malaria.ConclusionsStunting, indicative of chronic malnutrition, was associated with an increased incidence of malaria among a cohort of HIV-infected and -uninfected young children living in an area of high malaria transmission intensity. However, caution should be made when making causal inferences given the observational study design and inability to disentangle the temporal relationship between malnutrition and the incidence of malaria.Trial RegistrationClinicalTrials.gov: NCT00527800.