The impact of health on labour market outcomes: A rapid systematic review

The relationship between an individual's health and their labour market outcomes has long been a subject of health economics research. This review aims to provide an up-to-date, global review of the substantive findings in the existing literature. We pay particular attention to causal effects, acknowledging the methodological complexities that have long challenged the research and emphasizing the importance of overcoming them to present robust, policy-relevant evidence. The recent literature shows a notable advancement in addressing these methodological issues compared to previous work. The evidence reviewed suggests that individuals with better health overwhelmingly exhibit higher earnings and often enhanced labour supply. These findings extend beyond geographical boundaries, as evidence from diverse regions underscores the global significance of this association. The review covers evidence from a wide range of health indicators and conditions - including e.g. self-reported health, chronic diseases, disability, nutritional health, infections, mental health, addictions and others. Within and across the different health domains, the health-related factors exert varying degrees of influence on labour market outcomes, highlighting the multifaceted nature of the health-labour relationship and its potentially profound implications for individuals, communities, and economies.

Why we don't move: The importance of somatic maintenance and resting

A compelling ecological theory of movement and vigor must explain why humans and other animals spend so much time not moving. When we rest, our somatic maintenance systems continue to work. When our somatic maintenance requirements increase, we place greater subjective value on resting. To explain variation in movement and vigor, we must account for the subjective value of resting.

Chronic Energy Deficiency and Its Determinant Factors among Adults Aged 18-59 Years in Ethiopia: A Cross-Sectional Study

Background

The prevalence of undernutrition in low- and middle-income countries is still remarkably high. Undernutrition during adulthood is a greater risk factor for low productivity, poor health, and mortality. There is limited information on the prevalence and determinants of chronic energy deficiency in Ethiopia.

Objective

To assess the prevalence and determinants of chronic energy deficiency among adults aged 18–59 years in Ethiopia.

Method

A secondary data analysis was conducted using the data obtained from the 2016 Ethiopia Demographic and Health Survey. Data were collected using a multistage stratified cluster sampling technique, and the analytic sample consisted of 9,280 adults aged 18–59 years. The chi-square test and multivariable logistic regression analyses were used, and p value <0.05 was taken as statistically significant.

Result

A total of 9280 adults aged 18–59 years were included in the study and 2911 (28.7%) (95% CI: 27.0%–30.4%) of whom were chronic energy deficient. Adults who have no work (AOR = 1.41, 95% CI: 1.16, 1.72), male adults from Tigray region (AOR = 2.23, 95% CI: 1.61, 3.09), Afar region (AOR = 2.98, 95% CI: 2.04, 4.36), Somali region (AOR = 3.14, 95% CI: 2.19, 4.52), Gambella region (AOR = 1.89, 95% CI: 1.29, 2.76), Harari region (AOR = 1.54, 95% CI: 1.09, 2.19), Amhara region (AOR = 1.53, 95% CI: 1.09, 2.13), Oromia region (AOR = 1.53, 95% CI: 1.07, 2.19), Dire Dawa (AOR = 1.45, 95% CI: 1.03, 2.05), adults live lonely (AOR = 1.44, 95% CI: 1.21, 1.71), and adults residing in poor wealth index households (AOR = 1.26 : 95% CI: 1.07, 1.49) were significantly associated with chronic energy deficiency. Conclusion and recommendation. Chronic energy deficiency among male adults in Ethiopia was a high public health problem. Marital status, wealth index, occupation, and region were significant predictors of chronic energy deficiency. The Ministry of Health with other partners should strictly monitor and evaluate interventions that are being applied and should give focus to adult men to prevent malnutrition.

Determinants of objectively measured physical activity in rural East Timorese children

OBJECTIVES

The human juvenile period evolved as a period of learning and physical development in a family environment that subsidizes the costs of these processes. Children allocate energy to physical activity, maintenance, and growth. How energy is allocated has consequences for adult body size and other life-history traits. In subsistence agriculture populations, where child contributions to the household economy are common and energy availability is low, trade-offs in energy expenditure between activity and growth may help explain poor growth.

METHODS

Using accelerometry, we measured physical activity over 2 years in 88 free-living children aged 5-19 years in two ecologically varying communities in rural Timor-Leste. We model characteristics related to variation in activity, and subsequently, activity is modeled against growth, illness, and aspects of household and local ecology using linear mixed models.

RESULTS

Physical activity in Timorese children is characterized by high levels of moderate ( x ¯ = 8.8 h/day), no sustained vigorous, and little sedentary activity ( x ¯ = 4.6 h/day). Children in the mountainous community show a slight trade-off between activity and growth (P = .077). Males down-regulate both growth and activity relative to females. Variation in household characteristics does not predict child activity. Both activity and growth are lower in the mountainous community than in the flat, coastal community.

CONCLUSIONS

Household demands on child behavior may constrain children's ability to moderate activity relative to nutritional status. Activity in this population is high relative to other subsistence populations, possibly because children face the dual pressures of contributing to household subsistence and attending school.

Overview of Long-Term Nutrition Intervention Studies in Guatemala, 1968–1989

This is an overview of ten papers published in this issue of the Food and Nutrition Bulletin dealing with two components of a nutrition intervention study: the INCAP longitudinal study, 1969–1977, and the follow-up study, 1988–1989. The latter is a continuation of the former and seeks to test the hypothesis that nutritional improvements in early childhood lead to improved human capital formation in adolescents and young adults. Beneficial outcomes have been found to include greater body size and fat-free mass (particularly in females), improved working capacity in males, and enhanced intellectual performance in bath sexes.

Energy Expenditure, Duration of Activities, and Physical Work Capacities of Burmese Women Weavers

This study assesses the daily energy expenditure of Burmese women weavers and concludes that, although the total energy cost of their work is considerable because of the many hours involved, it is nor sufficiently intense either for substantial muscular development or for cardiovascular fitness. The weavers would not be able to tolerate work demanding high energy expenditure.

Nutrition, Health, and Economic Development: Some Policy Priorities

Most developing countries face different resource and infrastructural constraints that limit their economic growth. Nutritional deficiencies, poor environmental conditions, and inadequate educational infrastructure hamper children's learning, which is critical for the future supply of skilled labor and hence for economic development. There is a need to assign priorities for resource allocation among nutritional, health-care, and educational policies. This paper draws implications from several studies using data from less developed countries within a multidisciplinary framework. It concludes that iron supplementation of pregnant women and access to family-planning services are likely to enhance maternal and infant health. Where iodine deficiency is endemic, iodized salt is important for preventing cognitive damage to the fetus. Higher intakes of protein and micronutrients such as iron are important for children's physical growth, morbidity, and learning. Improved sanitation and vaccines against infections will prevent loss of vital nutrients. Investments in educational infrastructure, including adult literacy programs, are beneficial for children's cognitive development. Nutrition and health policies based on long-term considerations will lead to a well-trained labor force enabling non-resource-rich developing countries to escape from poverty traps.

Protein and Micronutrient Intakes Are Associated with Child Growth and Morbidity from Infancy to Adulthood in the Philippines

BACKGROUND

Interactions between nutrition and infections in developing countries are complex, and analyses of the interrelations require data from longitudinal studies that span several years and a comprehensive framework facilitating the formulation of food and health policies.

OBJECTIVE

The effects of dietary intakes in the Philippines for birth outcomes, heights, weights, and morbidity during ages 2-24 mo; heights and weights during ages 8-19 y; and completed adult heights were analyzed.

METHODS

Data on >3000 children from the Cebu Longitudinal Health and Nutrition Survey were modeled in 4 sets of analyses. Cross-sectional and multilevel models were estimated for length and weight at birth. Dynamic random-effects models were estimated for children's heights, weights, and morbidity levels during ages 2-24 mo. Children's heights and weights during ages 8-19 y were modeled by using random-effects models. Children's heights at age 22 y were modeled for investigating the effects of nutritional intakes in early childhood and in adolescence.

RESULTS

Maternal anthropometric indicators, energy intakes, and sociodemographic variables were significantly associated with children's length and weight at birth. Dynamic models for children's heights and weights during ages 2-24 mo showed significant effects of calcium and protein intakes; child morbidity levels were significantly associated with height and weight. Higher β-carotene intakes were significantly associated with lower morbidity levels. Analyses of data on children during ages 8-19 y showed significant effects of protein and calcium intakes and of morbidity levels on heights and weights. Models for children's heights at age 22 y indicated significant effects of protein and calcium intakes during early childhood and in adolescence.

CONCLUSIONS

The results underscored the need for formulating long-term food and health policies for the Philippines that enhance children's physical development and ultimately their adult stature, which is important for physical work capacity and labor productivity.

Health and adult productivity: the relation between adult nutrition, helminths, and agricultural, hunting, and fishing yields in the Bolivian Amazon

OBJECTIVES

Infectious disease and nutritional stress have both been associated with reductions in adult work productivity and work capacity in the context of wage labor, but less research has investigated their effects among groups relying on more traditional subsistence practices of horticulture and foraging. In this article, we examine the relations among measures of adult nutritional status (BMI, skinfold measurements, and fat-free mass) and infection (presence of soil transmitted helminth infections) and measures of adult work productivity.

METHODS

As part of a larger panel study among Tsimane', a foraging-horticulturalist group in the Bolivian Amazon, health surveys, anthropometric information, and the quantity of products (both crops and game) brought into the household were collected for 320 Tsimane' adults over a four-month period in 2003. In addition, a single fecal sample was collected for a sub-sample of 86 adults.

RESULTS

Our analysis shows mixed associations between either BMI or the presence of parasitism and reported adult productivity. Muscularity was not clearly related to adult productivity. In contrast, body fatness (Skinfold z-score) was inversely associated with the average quantity of fish and game brought into the household, especially for men.

CONCLUSIONS

These findings suggest that the effects of adult infection and nutritional stress may be less clearly identified outside of the context of wage labor. Further research linking adult physical activity levels and metabolic rates to productivity in diverse contexts is needed.

Physical fitness of normal, stunted and overweight children 6-13 years in Oaxaca, Mexico

BACKGROUND/OBJECTIVE

The objective of this study is to compare the growth and physical fitness of normal, stunted and overweight/obese (owt/ob) Oaxaca children 6-13 years.

SUBJECTS/METHODS

This study was a cross-sectional, included 688 school children (grades 1-3, 4-6), aged 6-13 years, from an indigenous rural community (n=361) and colonia popular (n=327) in Oaxaca, southern Mexico.

MEASUREMENTS

Anthropometry-weight, height, sitting height, limb circumferences, skinfolds. Derived-body mass index, sitting height/height ratio, leg and step lengths, limb muscle areas, sum of skinfolds. Physical fitness-sit and reach, sit-ups, distance run, grip strength, standing long jump, 35 yard dash. Physical activity-steps to and from school, household chores, sports participation.

ANALYSIS

Normal-not stunted, not owt/ob; stunted-not owt/ob; and owt/ob-not stunted were compared with multivariate analysis of covariance controlling for age. Two children were stunted and owt/ob, and were excluded.

RESULTS

Age-adjusted means for body size, muscularity, adiposity and grip strength showed a gradient, owt/ob>normal>stunted in both sexes and grade levels (P<0.001). Relative position of stunted and owt/ob children was reversed for strength per unit mass. Stunted and normal children ran a greater distance than owt/ob children (P<0.05). Normal, stunted and owt/ob children did not differ consistently in other fitness items and indicators of activity and inactivity.

CONCLUSION

Size, muscularity, fatness and strength differed significantly, owt/ob>normal>stunted, but owt/ob children had less strength per unit mass and poorer endurance. Normal and stunted children did not differ consistently in fitness. Physical activity and television time did not differ among the three groups.

Why no adult stunting penalty or height premium? Estimates from native Amazonians in Bolivia

Among adults of industrial nations, growth stunting (<-2 SD height Z score) is associated with worse indicators of adult well-being (e.g., income). Does adult stunting also inflict private costs in traditional societies? Adult stunting penalties or height premiums might only emerge when traditional societies modernize. Here we estimate the association between adult stunting and indicators of adult well-being using data from a panel study in progress among the Tsimane', a foraging-farming society of native Amazonians in Bolivia. Subjects included 248 women and 255 men >or=age 22 measured annually during 5 consecutive years (2002-2006). Nine outcomes (wealth, monetary income, illness, access to credit, mirth, schooling, math skills, plant knowledge, forest clearance) were regressed separately against a stunting dummy variable and a wide range of control variables. We found no significant association between any of the indicators of own well-being and adult stunting. Additional analysis showed that stunting bore an association only with poorer mid-arm muscle area. Height premiums and stunting penalties, though evident and marked in modern societies, might not be common in all traditional societies.

Life history trade-offs in human growth: Adaptation or pathology?

Human beings growing-up in adverse biocultural environments, including undernutrition, exposure to infection, economic oppression/poverty, heavy workloads, high altitude, war, racism, and religious/ethnic oppression, may be stunted, have asymmetric body proportions, be wasted, be overweight, and be at greater risk for disease. One group of researchers explains this as a consequence of "developmental programming" (DP). Another group uses the phrase "predictive adaptive response" (PAR). The DP group tends to view the alterations as having permanent maladaptive effects that place people at risk for disease. The PAR group considers the alterations at two levels of adaptation: (1) "short-term adaptive responses for immediate survival" and (2) "predictive responses required to ensure postnatal survival to reproductive age." The differences between the DP and PAR hypotheses are evaluated in this article. A life history theory analysis rephrases the DP versus PAR debate from disease or adaptation to the concept of "trade-offs." Even under good conditions, the stages of human life history are replete with trade-offs for survival, productivity, and reproduction. Under adverse conditions, trade-offs result in reduced survival, poor growth, constraints on physical activity, and poor reproductive outcomes. Models of human development may need to be refined to accommodate a greater range of the biological and cultural sources of adversity as well as their independent and interactive influences.

The effects of maternal education versus cognitive test scores on child nutrition in Kenya

This paper estimates dynamic random effects models for intakes by dietary energy, protein, calcium, iron, zinc, niacin, riboflavin, thiamin, and vitamins A, C, D, and E 100 of Kenyan school children (6-9 years) within a multivariate longitudinal framework. The explanatory variables were socioeconomic and background variables, children's body mass index, and maternal education, cognitive test scores and morbidity spells. The model parameters are estimated using the maximum likelihood method controlling for unobserved between-children differences. The main finding is that while maternal education was usually not a significant predictor of dietary intakes, maternal scores on cognitive tests did strongly predict them. Moreover, the paternal cognitive scores and maternal morbidity levels were not significantly associated with the intakes, but an index of socioeconomic status and cash income was a significant predictor. The results indicate the need to consider broader measures of human development and of devising suitable educational programs for women without formal education.

Providing Micronutrients through Food-Based Solutions: A Key to Human and National Development

To alleviate poverty in developing countries, economies must grow. Without the necessary investments in human capital, national economic growth may not lead to poverty alleviation and socioeconomic development, nor be sustainable. Economic growth that leads to poverty alleviation is fueled by the creative and physical capacities of people. The impact of micronutrient malnutrition is established early in life, leading to growth stunting, lower cognitive abilities, lethargy and poor attention, and greater severity and rates of infection. These effects limit educational progress, physical work capacity and life expectancy, thereby reducing individual lifetime productivity and the aggregate ability of the population to enhance its well-being and participate in national and global markets. The diets of the poor are largely cereal-based, monotonous and lacking in diversity and micronutrients. Animal source foods (ASF) have been an important factor in human evolution, a component of what was an historically diverse diet and an important source of micronutrients. Poverty and micronutrient malnutrition positively influence each other. This poverty micronutrient malnutrition (PMM) trap requires outside inputs to change the state of development in developing countries. Nutrition interventions have been excellent investments in development. More productive interaction between agricultural scientists and nutritionists, supported by a strong federal agenda for development, is needed to break the PMM trap. In the end, food is the means by which nutrients are delivered. Food-based approaches will require long-term commitments, but are more likely to be sustainable because they are part of a development process that leads to long-term economic growth.

Factors affecting the work productivity of Oraon agricultural laborers of Jalpaiguri district, West Bengal

In developing countries like India, where the incidence of protein-calorie malnutrition is high and mechanization is at a minimum, human labor provides much of the power for physical activity. This study presents anthropometric measurements, somatotypes, food intakes, energy expenditures, and work outputs of Oraon agricultural laborers of the Jalpaiguri district, West Bengal, in an attempt to identify the factors that predict high work productivity. Specifically, this study investigates 1) the relationship between morphological variation (anthropometric measurements and somatotype) and work productivity, 2) the nature and extent of the relationship between nutritional status and work productivity, and 3) the best predictor variables of work output. Classification of groups on the basis of median values of work output show that in the aggregate, the high productive groups are significantly younger than low-productive groups in both sexes. Before age-adjustment, the high productive groups show higher mean values of a few body dimensions, though these differ by sex, and both males and females exhibit a normal range of blood pressure and pulse rate values. Mean values of grip strength and back strength are higher in high-output men and women. Mean values of both food intake and energy expenditure are also higher among men in high-output groups, with only food intake higher in high-output women. However, after eliminating the effects of age, the differences between low-productive groups and high-productive groups in most of the variables are not significant. Productivity predictors in males consist of age, food intake and chest girth (inhalation). Females, on the other hand, show age and grip strength (left) as work output predictors.

Porters of the eastern hills of Nepal: Body size and load weight

This study documents the activities of 635 porters transporting goods along three traditional trade routes of eastern Nepal. Nearly 95% of the porters were male. They ranged in age from 10-65 years, and most of them had begun to perform long-distance portage at 12-15 years of age. Mean body mass and height of adult males in the combined sample (n = 438) was 49.7 +/- 5.0 kg and 155.5 +/- 6.5 cm, respectively. Adult males age 20-49 years carried loads of 73 +/- 15 kg, equivalent to 146% +/- 30% of body mass. Body size of adult males was not a strong predictor of load weight. The correlation between body mass and load was r = 0.24 (P < 0.0001), and between height and load was r = 0.16 (P < 0.001). Another significant determinant of load weight was whether the load was carried for profit or for domestic use. The most reasonable explanation for the ability of Nepali porters to carry such large loads in spite of their small body size is the ability to pace themselves by making frequent rest stops. Heart rate monitoring of 26 adult male commercial porters demonstrated how porters regulate heart rate and energy expenditure by resting the load every two to three minutes on the T-headed walking stick (tokma) and by setting the load periodically on load-resting platforms (chautaras) for longer recovery periods. Am. J. Hum. Biol. 11:1-11, 1999. Copyright 1999 Wiley-Liss, Inc.

Modeling the effects of nutritional and socioeconomic factors on the growth and morbidity of Kenyan school children

This paper estimates dynamic models for the height, head circumference, weight, and morbidity of approximately 110 Kenyan school children (6-9 years) in a multivariate longitudinal data framework. Dynamic models allow anthropometric dimensions to depend on the respective measurements in the previous period. The system of 4 equations specified for height, head circumference, weight, and morbidity incorporates the inter-relationships among these variables; explanatory variables in the model consist of nutritional, socioeconomic, demographic, and environmental factors. The model parameters are estimated using the principle of maximum-likelihood, while controlling for the unobserved between-children differences. The main findings are, first, that calcium intakes are positively associated with height while protein and energy intakes are associated with weight. Vitamin A intakes are negatively associated with morbidity. Second, socioeconomic status plus the cash income of the household is a significant predictor of height, head circumference, and morbidity. Third, maternal height is positively associated with children's height and maternal body mass index (BMI) is positively associated with children's weight. Fourth, parents' scores on psychological tests, mother's age, and children's hemoglobin concentration are negatively associated with morbidity while mothers' morbidity is positively associated with children's morbidity. Implications of the modeling results are discussed. Am. J. Hum. Biol. 11:317-326, 1999. Copyright 1999 Wiley-Liss, Inc.

Modeling the effects of health on economic growth

This paper investigates the effects of health indicators such as adult survival rates (ASR) on GDP growth rates at 5-year intervals in several countries. Panel data were analyzed on GDP series based on purchasing power adjustments and on exchange rates. First, we developed a framework for modeling the inter-relationships between GDP growth rates and explanatory variables by re-examining the life expectancy-income relationship. Second, models for growth rates were estimated taking into account the interaction between ASR and lagged GDP level; issues of endogeneity and reverse causality were addressed. Lastly, we computed confidence intervals for the effect of ASR on growth rate and applied a test for parameter stability. The results showed positive effects of ASR on GDP growth rates in low-income countries.

Women's health and pregnancy outcomes: do services make a difference?

We use data from the Indonesia Family Life Survey to investigate the impact of a major expansion in access to midwifery services on health and pregnancy outcomes for women of reproductive age. Between 1990 and 1998 Indonesia trained some 50,000 midwives. Between 1993 and 1997 these midwives tended to be placed in relatively poor communities that were relatively distant from health centers. We show that additions of village midwives to communities between 1993 and 1997 are associated with a significant increase in body mass index in 1997 relative to 1993 for women of reproductive age, but not for men or for older women. The presence of a village midwife during pregnancy is also associated with increased birthweight. Both results are robust to the inclusion of community-level fixed effects, a strategy that addresses many of the concerns about biases because of nonrandom program placement.

Modeling the effects of maternal nutritional status and socioeconomic variables on the anthropometric and psychological indicators of Kenyan infants from age 0-6 months

This paper presents a comprehensive empirical analysis of the factors affecting growth and psychological development of over 100 infants from birth to age 6 months in the Embu region of Kenya. The analysis was divided into four parts. First, infants' birth weight, and length and head circumference as measured few days after birth, were modeled using multiple regression models. Maternal prepregnancy body mass index (BMI), gestation period, and parity were associated with infants' anthropometric measurements (P < 0.05). Second, the scores on seven clusters of the Brazelton Neonatal Behavioral Assessment Scale were explained by health and socioeconomic indicators. While the models had poor predictive power, the scores were comparable to those reported in the literature for Puerto Rican and African American infants. The third part of the analysis modeled infant growth between 1-6 months by analyzing longitudinal data on length, head circumference, and weight. Dynamic models were postulated for the effects of nutritional, socioeconomic, and environmental factors and morbidity on anthropometric variables. The results showed that infants' calcium intakes were positively associated with length (P < 0.05). Maternal BMI and hemoglobin concentration were positively associated with infant weight (P < 0. 05); infant morbidity was negatively associated with weight (P < 0. 05). Lastly, the infants' scores at 6 months on the Bayley Motor Scale and on eight items from the Bayley Infant Behavior Record were explained using anthropometric, socioeconomic, and psychological variables. The infants' arm circumference and intake of protein were significant predictors of scores on the Bayley Motor Scale. In addition, time spent by the mother talking to the infant was positively associated with the scores on the Bayley Infant Behavior Record. The empirical results have implications for identifying vulnerable children in developing countries.

Gastrointestinal parasitic infection, anthropometrics, nutritional status, and physical work capacity in Colombian boys

This article tests the hypothesis that the presence of gastrointestinal parasites in Colombian boys is negatively associated with anthropometric characteristics, physical work capacity, blood hemoglobin (Hb) levels, and nutritional status. Anthropometric, Hb, &Vdot;O(2) max, and parasite load data were collected on 1,016 boys in Cali, Colombia. The boys were classified as lower socioeconomic class (SEC) from either urban or rural environments, and upper SEC from an urban environment. Sixty-three percent of the boys were infected with gastrointestinal parasites and, of the infected boys, 80-95% had light parasite loads. Parasites found included Necator americanus, Ascaris lumbricoides, Entamoeba histolytica, Trichuris trichiura, Giardia spp., and Enterobius vermicularis. Infected boys had significantly lower weight, stature, weight-for-height (among 6-9-year-old boys), Hb levels, and &Vdot;O(2) max (ANCOVA, controlling for age and SEC). In terms of nutritional status, infected boys were 1.47 times more likely to be classified as iron deficient than noninfected boys (chi-square, P < 0.001), and 1.61 times more likely to be classified as stunted (P < 0.001). Infection was not associated with wasting in any SEC group. In conclusion, light to moderate gastrointestinal parasite loads were associated with significantly lower weight, stature, weight-for-height (in 6-9-year-old boys), Hb levels, and &Vdot;O(2) max, and a significantly higher frequency of IDA and stunting. These data suggest that comprehensive analyses of the nutritional status of populations in regions endemic for parasitic infection should include testing for the presence of infection. Am. J. Hum. Biol. 11:763-771, 1999. Copyright 1999 Wiley-Liss, Inc.

Household headship and nutritional status: Female-headed versus male/dual-headed households

Approximately one-third of all poor urban households in Latin America are headed by females. This study compares the nutritional status of women and children from female-headed (FHH) and male/dual headed (MHH/DHH) households in economically disadvantaged neighborhoods in Cali, Colombia. Data collected included socioeconomic indicators, anthropometric dimensions, dietary intake, and interviews documenting household composition. Classification of household headship was based on the acknowledged head and the primary economic provider of the household. Of the households in this study, 81 (80%) were from MHH/DHHs and 20 (20%) from FHHs. FHHs had fewer material possessions and lived in houses made of less expensive materials compared to MHH/DHHs. However, there were no significant differences in the nutritional status of women or children in FHHs vs MHH/DHHs. Most women had BMIs within the normal range (19-29 kg/m² ). The majority of children (95%) had weight-for-height z-scores within ±2 of the NCHS references. These results suggest that while FHHs in Cali were economically poorer, the women studied appeared to have had access to sufficient food sources for themselves and their children. Am. J. Hum. Biol. 10:699-709, 1998. © 1998 Wiley-Liss, Inc.

Living on the edge: dietary strategies of economically impoverished women in Cali, Colombia

Economically impoverished women in Cali, Colombia, have restricted access to food in a city where food is abundant. Ethnographic observations, interviews and 2 day food records were used to better understand the coping strategies used by a group of these women (n = 85) to maintain adequate levels of energy intake. Anthropometric indicators of nutritional status were normal for the group. Interview data revealed that the ability to purchase food was a concern for 58% of the women. When faced with a restricted ability to purchase food, the women indicated they made compromises in meal composition, reduced portion sizes, and/or reduced the number of meals. They also relied on relatives, friends, neighbors, store credit, or local government programs for access to food. Changes in meal composition were identified in 17.1% of all diet records (n = 509). Low energy intake (defined as energy intake < or = 1.27 x BMR) was identified in 17.1% of all diet records. Carbohydrate consumption was significantly greater on low-energy intake days. The adequate nutritional status of this group of women suggests that their coping strategies are usually adequate to maintain energy intake, but the presence of uncertainty, the frequency of compromises in diet composition, and the frequency of low-energy intake days suggest that these women are at risk for undernutrition.

Plasticity, political economy, and physical growth status of Guatemala Maya children living in the United States

Migration of Maya refugees to the United States since the late 1970s affords the opportunity to study the consequences of life in a new environment on the growth of Maya children. The children of this study live in Indiantown, Florida, and Los Angeles, California. Maya children between 4 and 14 years old (n = 240) were measured for height, weight, fatness, and muscularity. Overall, compared with reference data for the United States, the Maya children are, on average, healthy and well nourished. They are taller and heavier and carry more fat and muscle mass than Maya children living in a village in Guatemala. However, they are shorter, on average, than children of black, Mexican-American, and white ethnicity living in Indiantown. Children of Maya immigrants born in the United States tend to be taller than immigrant children born in Guatemala or Mexico. Families that invest economic and social resources in their children have taller children. More economic successful families have taller children. Migration theory and political economy theory from the social sciences are combined with plasticity theory and life history theory (parental investment) from biology to interpret these data.

Reduced postexercise recovery oxygen consumptions: an adaptive response in chronic energy deficiency?

Maximal aerobic capacity (VO2max) and oxygen consumption during recovery were measured in well-nourished control subjects (C) and compared with results from chronically energy-deficient (CED) subjects in the same age range. The absolute VO2max was lower in undernourished subjects (2.5 +/- 0.1 L/min [C] v 1.8 +/- 0.1 L/min [CED]; mean +/- SEM, P < .001); however, when expressed per kilogram fat-free mass (FFM), the values were comparable. The total O2 debt was higher in the well-nourished group even when corrected for FFM differences (249.1 +/- 17.1 v 147.3 +/- 9.2 mL/kg FFM; P < .001). O2 consumption in the recovery period returned to baseline values rapidly and in a single phase in undernourished subjects. In contrast, a slow biphasic decline was observed in well-nourished control subjects. The postexercise recovery phase may be an important period during which energy-saving may occur in chronically undernourished human subjects.

Net mechanical efficiency during stepping in chronically energy-deficient human subjects

Mechanical efficiency during a step test was measured in chronically energy-deficient (CED) individuals and compared to well-nourished subjects using a whole-body indirect calorimeter. The CED group had significantly higher net mechanical efficiencies than the well nourished subjects. This was also evident in the 15% lower energy costs observed in the CED subjects when expressed as a percentage of the predicted data. Factors such as a higher proportion of slow muscle fibres as well as a greater ergonometric efficiency may contribute to the observed higher muscular efficiency aiding conservation of energy expenditure in these individuals.

Improvements in physical fitness of Kenyan schoolboys infected with hookworm, Trichuris trichiura and Ascaris lumbricoides following a single dose of albendazole

We studied physical fitness with the Harvard step test (HST), in primary schoolboys infected with hookworm (91% baseline prevalence), Trichuris trichiura (94%) and Ascaris lumbricoides (39-40%) who received a single 400 mg dose of albendazole or an identical placebo. Boys were examined, allocated at random to placebo or albendazole groups, treated, and re-examined 7 weeks later. The 2 groups did not differ significantly before treatment in age, anthropometry, haemoglobin levels, prevalence or intensity of the 3 helminth infections, or in initial HST fitness scores and heart rates. Seven weeks after treatment, the albendazole group (n = 18) exhibited significant improvements in fitness scores and heart rates at 1, 2, 3, and 4 min after the HST while in the placebo group (n = 15) these quantities had not changed significantly. After treatment, the albendazole group had significant decreases in the logarithmic egg counts for hookworm (80% reduction in arithmetic means) and A. lumbricoides (100% reduction); T. trichiura egg counts did not change significantly. The placebo group showed a borderline increase in the logarithms of hookworm egg counts and no significant change in T. trichiura and A. lumbricoides egg counts. Multiple regression analysis showed that the significant linear predictors of increase in HST score after treatment were decrease in resting heart rate after treatment, and decreases in hookworm egg counts and logarithms of A. lumbricoides egg counts after treatment. We conclude that single dose treatment with albendazole, despite continual exposure to reinfection, can allow improved physical fitness in schoolboys in areas where soil-transmitted helminths and protein-energy malnutrition are highly prevalent.

Adaptive significance of small body size: strength and motor performance of school children in Mexico and Papua New Guinea

The postulated superior functional efficiency in association with reduced body size under conditions of chronic protein-energy undernutrition was considered in school children from rural Mexico and coastal Papua New Guinea. Grip strength and three measures of motor performance were measured in cross-sectional samples of children 6-16 years of age from a rural agricultural community in Oaxaca, Mexico, and from the coastal community Pere on Manus Island, Papua New Guinea. The strength and performance of a mixed-longitudinal sample of well nourished children from Philadelphia was used as a reference. The Oaxaca and Pere children are significantly shorter and lighter and are not as strong as the well nourished children. Motor performances of Pere children compare favorably to those of the better-nourished Philadelphia children, whereas those of the Oaxaca children are poorer. Throwing performance is more variable. When expressed relative to body size, strength is similar in the three samples, but the running and jumping performances of Pere children per unit body size are better than the relative performances of Oaxaca and Philadelphia children. Throwing performance per unit body size is better in the undernourished children. The influence of age, stature, and weight on the performance of Oaxaca and Pere children is generally similar to that for well nourished children. These results suggest that the hypothesized adaptive significance of small body size for the functional efficiency of populations living under conditions of chronic undernutrition varies between populations and with performance tasks.

Genetic and environmental effects on growth of children from a subsistence agricultural community in southern Mexico

Sibling correlations for size attained in height, weight, sitting height, estimated leg length, the triceps skinfold, arm circumference, and estimated midarm muscle circumference were compared in 6- through 13-year-old schoolchildren grouped by household socioeconomic status. The children were residents of a Zapotec-speaking, subsistence agricultural community in the Valley of Oaxaca in southern Mexico. Sibling pairs were classified as being from high and low socioeconomic status (SES) households, and sibling correlations were computed within each SES group controlling for environmental effects derived from a factor analysis of information on household demography and land and livestock holdings. Like-sex siblings from lower SES households have significantly different correlations in four instances. Correlations are higher for leg length in lower SES brothers and higher for sitting height and weight in lower SES sisters, while the correlation for sitting height is higher in upper SES brothers. The sibling correlation results are not entirely consistent with observations on growth status by SES, particularly if the power and similarity of a common environment is the only cause of higher sibling correlations. Reduced body size under poorer socioeconomic and presumably nutritional circumstances is apparent, but it is not possible in this analysis to distinguish whether genotypic (developmental) plasticity or genetic adaptation, or both, are involved.