Elevated acute-phase protein in stunted Nepali children reporting low morbidity: different rural and urban profiles

C-reactive protein (CRP) in high altitude Bolivian peri-urban adolescents varies by adiposity, current illness, height, socioeconomic status, sex, and menarcheal status: The potential benefits and costs of adipose reserves in arduous environments

OBJECTIVES

In non-industrialized and low-income populations, adipose stores can serve as a valuable buffer against harsh conditions such as seasonal food scarcity. However, these reserves may incur costs due to adipocytes' production of pro-inflammatory cytokines; inflammation is associated with increased risk for cardiometabolic diseases later in life. Life history theory posits that, especially in populations with high juvenile mortality, higher adiposity may nonetheless be advantageous if its benefits in early life outweigh its later costs. Relatively little is known about adolescents' C-reactive protein concentration (CRP; an inflammation biomarker) in such environments. We investigated CRP and its associations with several hypothesized predictors in adolescents in an economically diverse peri-urban Andean community.

METHODS

We measured CRP in dried blood spots and collected data on anthropometrics, illnesses, socioeconomic status (SES), and menarcheal status in 59 female and 40 male adolescents ("Alteños", 11.0-14.9 years old) with normal vital signs in El Alto, Bolivia (~4150 m amsl). We used Cole's LMS method to standardize all anthropometrics for sex and age, and principal components analysis to construct a "fat-factor" variable loading on these standardized z-scores. We used multiple linear regression to assess the influence of fat-factor and other likely predictors on CRP rank.

RESULTS

Compared to a national Bolivian growth reference, Alteños were, on average, shorter and leaner; only 6% were classified as overweight and none were obese. Pre-menarche females were on average leaner than post-menarche females. The best-fitting model explained 24% of the variance in CRP rank. Significant predictors were fat-factor, SES, current illness for males and pre-menarche females, and z-height for females.

CONCLUSIONS

Our results are consistent with a tradeoff between investments in growth versus immune functioning, as might be expected in an environment with limited resources and high pathogen exposure (e.g., soil-transmitted helminths, poor sanitation). Thinner Alteños appear to maintain a minimum CRP concentration independent of fat-factor, while fatter (or less-thin) Alteños' CRP rises with fat-factor. Female Alteños appear to be trading off investment in immune response for investment in growth and maturation. Alteños' high rate of stunting and absence of obesity suggests chronic, presumably multifactorial, stress. Adipose stores likely buffer against some of these stressors and, in an environment such as this-in which many lack sufficient nutritious foods, potable water, adequate sewage, and health care-may confer a net lifetime benefit.

Adiposity and pathogen exposure: An investigation of response to iron supplementation and hypothesized predictors in anemic pre-school-aged children living in a dual burden environment

OBJECTIVES

Peruvians are experiencing rapid dietary and lifestyle changes, resulting in a phenomenon known as the "dual burden of disease." A common manifestation of the dual burden in individuals is the co-occurrence of overweight and anemia. Despite recent initiatives introduced to address these concerns, rates continue to be public health concerns. This study investigates the relationship between immune activation and lack of response to iron supplementation after 1 month of treatment and explores variation in body fat stores as a potential moderator between immune function and response to treatment.

METHODS

Data come from children, aged 2-5 years (n = 50) from a peri-urban community in Lima, Peru. Multivariate logistic regression models were used to explore the associations between response to treatment (Hb > =11.0 g/dl) after 1 month of treatment), markers of immune activation (C-reactive protein [CRP] and reported morbidity symptoms), and measures of body fat (waist-to-height ratio, triceps skinfold thickness, and body mass index [BMI]).

RESULTS

We found that high CRP is associated with a lack of response to iron supplementation after 1 month of treatment and that BMI z-score may moderate this association. Generally, larger body size is associated with response to iron supplementation whether or not the children in this sample have high immune activation. However, the probability of anemic children responding to iron supplementation treatment differed across adiposity measures.

CONCLUSIONS

Our finding suggesting that adiposity and CRP influence response to iron supplementation, furthers our understanding of the relationship between inflammation and anemia treatment in children and has both theoretical and public health implications.

Early maturity, shortened stature, and hardship: Can life-history trade-offs indicate social stratification and income inequality in the United States?

OBJECTIVE

Life-history strategies promote reproductive fitness and survival. Limited energy availability and competing energetic demands between life-history decisions may result in organismal trade-offs leading to selection for "optimal" traits that facilitate fitness and survival in present environmental conditions. Few life-history analyses have been conducted in food abundant/high resource human populations. Here, we use a life-history theory framework integrated with a biocultural approach to assess whether trade-offs between growth (height) and the onset of reproductive maturation (ages at menarche) were observed in a sample of adult women living in the United States.

METHODS

Adult women (18 years and older) from the National Health and Nutrition Examination Survey (NHANES) 2005 to 2006 were analyzed using complex survey regression to evaluate associations between ages at menarche, height, and biological, socio-economic, demographic, and anthropometric variables. Associations between stature, ages at menarche, and socio-economic status (household income and education level) suggest life-history trade-offs in this populations may be mitigated by access to resources and marginalization.

CONCLUSIONS

These study results have applied public health implications. We demonstrate that females who experience early menarche in the US population achieve short stature. Our study also demonstrates the need for implementing life-history analyses in Western affluent populations, where marginalization may result in life-history trade-offs.

Dietary Patterns and Dietary Adequacy of Street Children in Dhaka, Bangladesh

The negative impact of poverty on the biological well-being of children is well established. The purpose of the present study was to evaluate the impact of the stress of full-time street life on the dietary patterns and dietary adequacy of street children living in Dhaka, Bangladesh. This was accomplished by comparing the nutritional patterns of full-time street children with those of other poor children in Dhaka who also spend their days on the streets but who return to their families at night. There were few differences between groups, possibly due to street children being a select group. However, there were significant sex differences in both groups of children, with boys tending to have more diverse and more adequate diets than girls. The cause of this latter pattern could not be determined with the available data but may involve cultural values favoring males over females.

Evolutionary public health: introducing the concept

The emerging discipline of evolutionary medicine is breaking new ground in understanding why people become ill. However, the value of evolutionary analyses of human physiology and behaviour is only beginning to be recognised in the field of public health. Core principles come from life history theory, which analyses the allocation of finite amounts of energy between four competing functions-maintenance, growth, reproduction, and defence. A central tenet of evolutionary theory is that organisms are selected to allocate energy and time to maximise reproductive success, rather than health or longevity. Ecological interactions that influence mortality risk, nutrient availability, and pathogen burden shape energy allocation strategies throughout the life course, thereby affecting diverse health outcomes. Public health interventions could improve their own effectiveness by incorporating an evolutionary perspective. In particular, evolutionary approaches offer new opportunities to address the complex challenges of global health, in which populations are differentially exposed to the metabolic consequences of poverty, high fertility, infectious diseases, and rapid changes in nutrition and lifestyle. The effect of specific interventions is predicted to depend on broader factors shaping life expectancy. Among the important tools in this approach are mathematical models, which can explore probable benefits and limitations of interventions in silico, before their implementation in human populations.

Factors associated with inflammation in preschool children and women of reproductive age: Biomarkers Reflecting Inflammation and Nutritional Determinants of Anemia (BRINDA) project

Background: In many settings, populations experience recurrent exposure to inflammatory agents that catalyze fluctuations in the concentrations of acute-phase proteins and certain micronutrient biomarkers such as C-reactive protein (CRP), α-1-acid glycoprotein (AGP), ferritin, and retinol. Few data are available on the prevalence and predictors of inflammation in diverse settings.Objective: We aimed to assess the relation between inflammation (CRP concentration >5 mg/L or AGP concentration >1 g/L) and covariates, such as demographics, reported illness, and anthropometric status, in preschool children (PSC) (age range: 6-59 mo) and women of reproductive age (WRA) (age range: 15-49 y).Design: Cross-sectional data from the Biomarkers Reflecting Inflammation and Nutritional Determinants of Anemia (BRINDA) project from 29,765 PSC in 16 surveys and 25,731 WRA in 10 surveys were used to model bivariable and multivariable relations.Results: The inflammation prevalence was 6.0-40.2% in PSC and 7.9-29.5% in WRA (elevated CRP) and 21.2-64.3% in PSC and 7.1-26.7% in WRA (elevated AGP). In PSC, inflammation was consistently positively associated with recent fever and malaria but not with other recent illnesses. In multivariable models that were adjusted for age, sex, urban or rural residence, and socioeconomic status, elevated AGP was positively associated with stunting (height-for-age z score <-2) in 7 of 10 surveys. In WRA, elevated CRP was positively associated with obesity [body mass index (in kg/m²) ≥30] in 7 of 9 surveys. Other covariates showed inconsistent patterns of association with inflammation. In a pooled analysis of surveys that measured malaria, stunting was associated with elevated AGP but not CRP in PSC, and obesity was associated with both elevated CRP and AGP in WRA.Conclusions: Recent morbidity and abnormal anthropometric status are consistently associated with inflammation across a range of environments, whereas more commonly collected demographic covariates were not. Because of the challenge of defining a general demographic population or environmental profile that is more likely to experience inflammation, inflammatory markers should be measured in surveys to account for their effects.

Energetics and the immune system: Trade-offs associated with non-acute levels of CRP in adolescent Gambian girls

Background and objectives: The human immune system is an ever-changing composition of innumerable cells and proteins, continually ready to respond to pathogens or insults. The cost of maintaining this state of immunological readiness is rarely considered. In this paper we aim to discern a cost to non-acute immune function by investigating how low levels of C-reactive protein (CRP) relate to other energetic demands and resources in adolescent Gambian girls.

Methodology: Data from a longitudinal study of 66 adolescent girls was used to test hypotheses around investment in immune function. Non-acute (under 2 mg/L) CRP was used as an index of immune function. Predictor variables include linear height velocity, adiposity, leptin, and measures of energy balance.

Results: Non-acute log CRP was positively associated with adiposity (β = 0.16, P < 0.001, R² = 0.17) and levels of the adipokine leptin (β = 1.17, P = 0.006, R² = 0.09). CRP was also negatively associated with increased investment in growth, as measured by height velocity (β = −0.58, P < 0.001, R² = 0.13) and lean mass deposition β = −0.42, P = 0.005, R² = 0.08). Relationships between adiposity and growth explained some, but not all, of this association. We do not find that CRP was related to energy balance.

Conclusions and implications: These data support a hypothesis that investment in non-acute immune function is facultative, and sensitive to energetic resources and demands. We also find support for an adaptive association between the immune system and adipose tissue.

Undernutrition, the acute phase response to infection, and its effects on micronutrient status indicators

Infection and undernutrition are prevalent in developing countries and demonstrate a synergistic relation. Undernutrition increases infection-related morbidity and mortality. The acute phase response (APR) is an innate, systemic inflammatory reaction to a wide array of disruptions in a host's homeostasis, including infection. Released from immune cells in response to deleterious stimuli, proinflammatory cytokines act on distant tissues to induce behavioral (e.g., anorexia, weakness, and fatigue) and systemic effects of the APR. Cytokines act to increase energy and protein requirements to manifest fever and support hepatic acute phase protein (APP) production. Blood concentrations of glucose and lipid are augmented to provide energy to immune cells in response to cytokines. Additionally, infection decreases intestinal absorption of nutrients and can cause direct loss of micronutrients. Traditional indicators of iron, zinc, and vitamin A status are altered during the APR, leading to inaccurate estimations of deficiency in populations with a high or unknown prevalence of infection. Blood concentrations of APPs can be measured in nutrition interventions to assess the time stage and severity of infection and correct for the APR; however, standardized cutoffs for nutrition applications are needed. Protein-energy malnutrition leads to increased gut permeability to pathogens, abnormal immune cell populations, and impaired APP response. Micronutrient deficiencies cause specific immune impairments that affect both innate and adaptive responses. This review describes the antagonistic interaction between the APR and nutritional status and emphasizes the need for integrated interventions to address undernutrition and to reduce disease burden in developing countries.

Significant sex difference in the association between C-reactive protein concentration and anthropometry among 13- to 19-year olds, but not 6- to 12-year olds in Nepal

Life history theory predicts a trade-off between immunostimulation and growth. Using a cross-sectional study design, this study aims to test the hypothesis that C-reactive protein (CRP) is negatively associated with height-for-age z-scores (HAZ scores) and BMI-for-age z-scores (BAZ scores) among 6- to 19-year olds (N = 426) residing in five Nepalese communities. Dried blood spot (DBS) samples were collected and assayed for CRP using an in-house enzyme immunoassay (EIA). Sex- and age-group-specific CRP quartiles were used to examine its association with growth in linear mixed-effects (LME) models. A significant difference was found in the proportion of elevated CRP (>2 mg/L, equivalent to ∼3.2 mg/L serum CRP) between 13- and 19-year-old boys (12%) and girls (4%). Concentrations of CRP were positively associated with HAZ score among adolescent (13-19 years) boys, which may indicate that individuals with greater energy resources have better growth and a better response to infections, thus eliminating the expected trade-off between body maintenance (immunostimulation) and growth. Adolescent boys with low BAZ and HAZ scores had low CRP values, suggesting that those who do not have enough energy for growth cannot increase their CRP level even when infected with pathogens. Among adolescent girls a positive association was observed between CRP and BAZ scores suggesting the possible effects of chronic low-grade inflammation due to body fat rather than infection. The association between CRP and growth was less evident among children (6-12 years) compared with adolescents, indicating that the elevated energy requirement needed for the adolescent growth spurt and puberty may play some role.

Pathogenic and obesogenic factors associated with inflammation in Chinese children, adolescents and adults

OBJECTIVES

Influenced by pathogen exposure and obesity, inflammation provides a critical biological pathway linking changing environments to the development of cardiometabolic disease. This study tests the relative contribution of obesogenic and pathogenic factors to moderate and acute CRP elevations in Chinese children, adolescents and adults.

METHODS

Data come from 8795 participants in the China Health and Nutrition Study. Age-stratified multinomial logistic models were used to test the association between illness history, pathogenic exposures, adiposity, health behaviors and moderate (1-10 mg/L in children and 3-10 mg/L in adults) and acute (>10mg/L) CRP elevations, controlling for age, sex and clustering by household. Backward model selection was used to assess which pathogenic and obesogenic predictors remained independently associated with moderate and acute CRP levels when accounting for simultaneous exposures.

RESULTS

Overweight was the only significant independent risk factor for moderate inflammation in children (RRR 2.10, 95%CI 1.13-3.89). History of infectious (RRR 1.28, 95%CI 1.08-1.52) and non-communicable (RRR 1.37, 95%CI 1.12-1.69) disease, overweight (RRR 1.66, 95%CI 1.45-1.89) and high waist circumference (RRR 1.63, 95%CI 1.42-1.87) were independently associated with a greater likelihood of moderate inflammation in adults while history of infectious disease (RRR 1.87, 95%CI 1.35-2.56) and overweight (RRR 1.40, 95%CI 1.04-1.88) were independently associated with acute inflammation. Environmental pathogenicity was associated with a reduced likelihood of moderate inflammation, but a greater likelihood of acute inflammation in adults.

CONCLUSIONS

These results highlight the importance of both obesogenic and pathogenic factors in shaping inflammation risk in societies undergoing nutritional and epidemiological transitions.

The health status of street children and youth in low- and middle-income countries: a systematic review of the literature

The health of the tens of millions of street children globally is understudied. We undertook a systematic review of the existing quantitative literature regarding the health status of street children and youth in low- and middle-income countries to summarize available knowledge, identify underexplored areas of research, and inform the future research agenda regarding the health of this population. A total of 108 articles met our inclusion criteria. Demographic data and structural factors associated with street life are summarized. Although data in specific regions or diseases are sparse, the literature review illustrates that youth's survival behaviors and the exposures associated with poor shelter have resulted in disproportionate morbidity in the areas of infectious illness, psychiatric disease, reproductive health, and perhaps to a lesser extent, growth. Vast areas of health that may disproportionately affect street children in childhood or later on as adults have not been investigated, including chronic diseases and cognitive deficits. Studies of specific diseases or conditions vary considerably by region. Strengths and limitations of the literature are discussed and principles for future research in this area are proposed.

Expanding the frontiers of population nutrition research: new questions, new methods, and new approaches

Nutrition research, ranging from molecular to population levels and all points along this spectrum, is exploring new frontiers as new technologies and societal changes create new possibilities and demands. This paper defines a set of frontiers at the population level that are being created by the increased societal recognition of the importance of nutrition; its connection to urgent health, social, and environmental problems; and the need for effective and sustainable solutions at the population level. The frontiers are defined in terms of why, what, who, and how we study at the population level and the disciplinary foundations for that research. The paper provides illustrations of research along some of these frontiers, an overarching framework for population nutrition research, and access to some of the literature from outside of nutrition that can enhance the intellectual coherence, practical utility, and societal benefit of population nutrition research. The frontiers defined in this paper build on earlier forward-looking efforts by the American Society for Nutrition and extend these efforts in significant ways. The American Society for Nutrition and its members can play pivotal roles in advancing these frontiers by addressing a number of well-recognized challenges associated with transdisciplinary and engaged research.

Sensitivity and specificity of C-reactive protein and α(1) -acid glycoprotein for episodes of acute infection among children in Kilimanjaro, Tanzania

OBJECTIVES

Biomarkers of inflammation, including C-reactive protein (CRP) and α(1) -acid glycoprotein (AGP), have tremendous potential in anthropological, public health, and nutrition research as objective indicators of acute infection; however, their usage is limited by the lack of widely agreed upon, reliable cutpoints to define infection. We assessed the sensitivity and specificity of CRP and AGP for identifying acute infectious disease (ID) episodes among children in the Kilimanjaro region of Tanzania.

METHODS

Data were available from 43 3- to 5-year-old children. CRP and AGP were measured in capillary whole dried blood spots (DBS). Two-week morbidity history interviews with children's primary caregivers were used to detect recent episodes of acute ID. Specimens and morbidity history interviews were collected from each child on one (n = 13) or two (n = 30) occasions for 73 paired interviews and specimens.

RESULTS

We evaluated CRP and AGP for identifying acute infection (report of fever, diarrhea, or vomiting in the last week): CRP ≥ 1.1 mg/l had sensitivity of 57.14% and specificity of 86.44%; AGP ≥ 0.76 g/l had sensitivity of 57.14% and specificity of 72.41%. The combined definition (AGP ≥ 0.76 g/l or CRP ≥ 1.1 mg/l) had sensitivity of 71.43% and specificity of 70.69%.

CONCLUSIONS

Among children in Kilimanjaro, Tanzania, assessed in whole blood stored as DBS, AGP ≥ 0.76 g/l or CRP ≥ 1.1 mg/l provided the best definition of acute infection. Whether this definition is appropriate for use in other populations remains to be determined.

C-reactive protein across the menstrual cycle

C-reactive protein (CRP) is a widely used, sensitive biomarker of inflammation. Studies conducted among users of exogenous hormones suggest that estrogen increases CRP, whereas progesterone decreases CRP. Examinations of CRP in normally cycling women suggest the opposite: CRP is negatively associated with endogenous estrogen and positively associated with endogenous progesterone. This work evaluates the association between menstrual cycle-related hormone changes and events (menstruation and ovulation) and CRP. Eight female subjects gave urine and blood samples from twelve days across the menstrual cycle, for a total of eleven cycles. Blood samples were assayed for CRP; urine samples for beta-follicle stimulating hormone (betaFSH), pregnanediol 3-glucuronide (PDG), and estrone glucuronide (E1G). Ovulation day was estimated using hormone levels. Presence or absence of menses was reported by subjects. Analyses were conducted with random-effects linear regression. All cycles were ovulatory; day of ovulation was identified for nine cycles. A ten-fold increase in progesterone was associated with a 23% increase in CRP (P = 0.01), a ten-fold increase in estrogen was associated with a 29% decrease in CRP (P = 0.05), and menses was associated with a 17% increase in CRP (P = 0.18); no association between ovulation or FSH and CRP was found. Hormone changes across the menstrual cycle should be controlled for in future studies of inflammation in reproductive-age women.

Pathways leading to early growth faltering: an investigation into the importance of mucosal damage and immunostimulation in different socio-economic groups in Nepal

Early childhood growth retardation persists in developing countries despite decades of nutritional interventions. Adequate food is necessary, but not sufficient, to ensure normal growth where there is ubiquitous exposure to infection. Pathways associated with infection, small intestinal mucosal damage and chronic immunostimulation remain largely undemonstrated in countries other than The Gambia. We conducted a longitudinal study of one squatter and one middle-class group (n 86, 3-18 month olds) to assess these relationships in Nepal. Growth, mucosal damage index (MDI; urinary lactose:creatinine ratio adjusted for body weight), morbidity reports, and blood concentrations of albumin, alpha-1-acid glycoprotein, IgG and Hb, were recorded monthly. Growth status worsened dramatically from 6 to 18 months, with squatters more stunted (height-for-age Z-score (HAZ), P<0.001) and underweight (weight-for-age Z-score (WAZ), P=0.009) than middle class. IgG increased with age, was elevated in squatter children, and negatively related to WAZ (P=0.034). MDI showed significant negative associations with growth performance, explaining 9 and 19% of height and weight deficits (DeltaHAZ, P=0.004; DeltaWAZ, P<0.001). Unexpectedly, these associations were weaker in squatter children, namely in the group which showed poorer growth, elevated morbidity, greater pathogen exposure (IgG) and higher MDI (P<0.001). In Nepal, as in The Gambia, children exhibit poor growth, mucosal damage and immunostimulation. The relative impact of pathways associated with infection and undernutrition may, however, differ across socio-economic groups: in poorer children, the impact of mucosal damage and immunostimulation could be masked by nutritional constraints. This has important implications for public health interventions.

Homeless street children in Nepal: use of allostatic load to assess the burden of childhood adversity

As challenges to child well-being through economic disadvantage, family disruption, and migration or displacement escalate world wide, the need for cross-culturally robust understanding of childhood adversity proportionately increases. Toward this end, developmental risk was assessed in four contrasting groups of 107 Nepali children ages 10-14 years that represent distinctive, common conditions in which contemporary children grow up. Relative cumulative burden (allostatic load) indexed by multiple dimensions of physical and psychosocial stress was ascertained among homeless street boys and three family-based groups, from poor urban squatter settlements, urban middle class, and a remote rural village. Biomarkers of stress and vulnerability to stress included growth status, salivary cortisol, antibodies to Epstein-Barr virus, acute phase inflammatory responses (alpha1-antichymotrypsin), and cardiovascular fitness and reactivity (flex heart rate and pressor response). Individual biomarkers of risk and allostatic load differed markedly among groups, were highest in villagers, and varied by components of allostatic load. Such data suggest a need for critical appraisal of homelessness and migration as a risk factor to youth, given prevailing local conditions such as rural poverty, and represents the only multidimensional study of childhood allostatic load and developmental risk in non-Western settings.

Life in the slow lane revisited: ontogenetic separation between chimpanzees and humans

This study investigates the evolution of human growth by analyzing differences in body mass growth trajectories among three populations: the Ache of eastern Paraguay, the US (NHANES, 1999-2000), and captive chimpanzees. The relative growth statistic "A" from the mammalian growth law is allowed to vary with age and proves useful for comparing growth across different ages, populations, and species. We demonstrate ontogenetic separation between chimpanzees and humans, and show that interspecific differences are robust to variable environmental conditions. The human pattern of slow growth during the lengthened period from weaning to the beginning of the adolescent growth spurt is found among the Ache (low energy availability and high disease load) and also in the US (high energy availability and low disease load). The human growth pattern contrasts with that of the chimpanzee, where absolute growth rates and relative "A" values are faster and less prolonged. We suggest that selection has acted to decrease human growth rates to allow more time for increased cognitive development with lower body-maintenance costs.

Does zinc deficiency play a role in stunting among primary school children in NE Thailand?

Stunting in school-age years may result in a decrease in adult size, and thus reduced work capacity and adverse reproductive outcomes. We have compared the mean intakes of energy, protein and selected growth-limiting nutrients in fifty-eight stunted children and 172 non-stunted controls drawn from 567 children aged 6–13 years attending ten rural schools in NE Thailand. Control children were selected randomly after stratifying children by age in each school. Dietary data were calculated from 24-h recalls using nutrient values from Thai food composition data and chemical analysis. Inter-relationships between stunting and sociodemographic, anthropometric and biochemical variables were also examined. Biochemical variables investigated were serum albumin, zinc, ferritin, transferrin receptor and retinol, and iodine in casual urine samples. Significantly more males than females were stunted (males, n 38, 65·5 % v. females, n 20, 34·5 %; P = 0·025). Stunted males had lower mean intakes of energy, protein, calcium, phosphorus and zinc, and a lower mean (95 % CI) serum zinc (9·19 (8·53, 9·84) v. 9·70 (8·53, 9·29) μmol/l) than non-stunted males; no other biochemical differences were noted. Stunted males also had a lower mean arm muscle area (P = 0·015), after adjusting for age, than non-stunted males. In conclusion, the lower dietary intakes of the stunted males compared to their non-stunted counterparts may be associated with anorexia and hypogeusia induced by zinc deficiency. Hence, zinc deficiency may be a factor limiting linear growth, especially among boys in NE Thailand, but more research is needed to establish whether other factors also play a role.

Relationships between biochemical bone turnover markers, season, and inflammatory status indices in prepubertal Gambian boys

Seasonal and interindividual differences in food availability and illnesses cause variations in growth, including bone growth, in children in developing countries. We investigated seasonal differences in biochemical (serum) markers of bone metabolism and relationships between these markers (procollagen type I N propeptide [P1NP], serum C-terminal telopeptide of type 1 collagen [S-CTX]) and serum markers of inflammation (alpha(1)- antichymotrypsin [ACT], C-reactive protein [CRP], sialic acid) in prepubertal Gambian boys. Three seasonal time points were chosen: August, mid-rainy season; October, late rainy season (both are associated with decreased food supply, increased prevalence of infection, reduced weight gain, and stunting); and April, late dry season, when environmental conditions are better and rates of weight gain are higher. The prevalence of raised inflammatory markers was high: 29% of ACT values >0.40 g/L in August, 42% >0.40 g/L in October, and 18% >0.40 g/L in April. Of CRP values, 92-96% were >0.47 mg/L and 30%, 46%, and 18% were >3.95 mg/L in August, October, and April, respectively. Also, 42-52% of sialic acid values were >648 mg/L. Of the bone markers, S-CTX exhibited the highest values in August; P1NP did not vary with season. Inverse relationships between each bone marker and the acute phase markers occurred, with the strongest relationships between P1NP and ACT or sialic acid. We conclude that bone collagen synthesis and turnover are reduced during inflammation in rural Gambian boys. Biochemical indices can provide powerful, single-time point evidence of infection and growth-faltering episodes.

Micronutrients in childhood and the influence of subclinical inflammation

In the present paper biomarkers of micronutrient status in childhood and some of the factors influencing them, mainly dietary intake, requirements and inflammation will be examined. On a body-weight basis the micronutrient requirements of children are mostly higher than those of an adult, but most biomarkers of status are not age-related. A major factor that is often overlooked in assessing status is the influence of subclinical inflammation on micronutrient biomarkers. In younger children particularly the immune system is still developing and there is a higher frequency of sickness than in adults. The inflammatory response rapidly influences the concentration in the blood of several important micronutrients such as vitamin A, Fe and Zn, even in the first 24 h, whereas dietary deficiencies can be envisaged as having a more gradual effect on biomarkers of nutritional status. The rapid response to infection may be for protective reasons, i.e. conservation of reserves, or by placing demands on those reserves to mount an effective immune response. However, because there is a high prevalence of disease in many developing countries, an apparently-healthy child may well be at the incubation stage or convalescing when blood is taken for nutritional assessment and the concentration of certain micronutrient biomarkers will not give a true indication of status. Most biomarkers influenced by inflammation are known, but often they are used because they are convenient or cheap and the influence of subclinical inflammation is either ignored or overlooked. The objective of the present paper is to discuss: (1) some of the important micronutrient deficiencies in childhood influenced by inflammation; (2) ways of correcting the interference from inflammation.

Growth rates and life histories in twenty-two small-scale societies

This study investigates variation in body growth (cross-sectional height and weight velocity) among a sample of 22 small-scale societies. Considerable variation in growth exists among hunter-gatherers that overlaps heavily with growth trajectories present in groups focusing more on horticulture. Intergroup variation tends to track environmental conditions, with societies under more favorable conditions displaying faster growth and earlier puberty. In addition, faster/earlier development in females is correlated with higher mortality. For example, African "Pygmies," Philippine "Negritos," and the Hiwi of Venezuela are characterized by relatively fast child-juvenile growth for their adult body size (used as a proxy for energetic availability). In these societies, subadult survival is low, and puberty, menarche, and first reproduction are relatively early (given their adult body size), suggesting selective pressure for accelerated development in the face of higher mortality. In sum, the origin and maintenance of different human ontogenies may require explanations invoking both environmental constraints and selective pressures.

Growth and health status of street children in Dhaka, Bangladesh

The purpose of this study was to assess the effect of street life on the growth and health status of poor children who live and work full-time on the streets of Dhaka, Bangladesh (street children), independent of the effects of poverty. This was accomplished by comparing 142 street children with 150 poor children who live and work on the streets of Dhaka but who return to their families at night (slum children). Children between 7-14 years old were recruited at locales where street and slum children are typically found. Weight and upper arm circumference did not differ significantly between street and slum children (P > 0.05), but energy reserves, as assessed by skinfolds, were significantly larger in street than in slum children (P < 0.05). There was no wasting in either street or slum children. Although the majority of children in both groups were stunted and underweight, there were no significant differences between groups (P > 0.05). The prevalence of disease symptoms tended to be slightly higher in street children than in slum children, but few of the differences were statistically significant (P < 0.05). These data do not support the contention that street children are a particularly high-risk group. The greater-than-expected growth and health status of street children, compared to other poor children, may be due to biologically fitter children being more likely to permanently move to the streets and/or to remain on the streets once the move has been made.

Infection, inflammation, height, and longevity

Using historical data from cohorts born before the 20th century in four northern European countries, we show that increasing longevity and declining mortality in the elderly occurred among the same birth cohorts that experienced a reduction in mortality at younger ages. Concurrently, these cohorts also experienced increasing adult height. We hypothesize that both the decline in old-age mortality and the increase in height were promoted by the reduced burden of infections and inflammation. Thus, early growth and cardiovascular diseases of old age may share infectious and inflammatory causes rooted in the external environment.

Immunostimulation and growth faltering in UK infants

The purpose of the study was to determine whether chronic immunostimulation could explain growth faltering in disadvantaged children in the UK, as it does in developing countries such as The Gambia. In all, 216 infants, age 10-21 months, were recruited when blood samples were taken for the routine or clinical purposes of a longitudinal study tracking a larger cohort of children. Aliquots of blood were collected on Guthrie cards to determine blood concentrations of albumin (Alb), alpha(1)-antichymotrypsin (ACT), and immunoglobulin G (IgG). Haemoglobin concentrations were determined by routine hospital laboratory analysis. Heights and weights were measured and converted to z-scores; birth weights were used with recruitment weight to calculate a 'thrive index' for each child. Age-corrected plasma IgG concentration was negatively associated with both height- and weight-for-age z-scores (P = 0.042 and 0.038, respectively) but not with the thrive index or body mass index z-scores. Blood haemoglobin levels were positively related to height- and weight-for age z-scores, as well as to the thrive index (P = 0.026, 0.014, and 0.007, respectively). Although significant, these relationships could only account for a small part the observed growth variation. Although the relationships were weak, the results suggest that some of the observed variation in growth of these UK infants may be explained on the basis of persistent immunostimulation or poor iron status. In terms of markers of immunostimulation (Alb, ACT, ACT:Alb ratio, IgG), both absolute levels and relationships with height-for-age are substantially different than those previously observed in cohort studies of infants in The Gambia.

Cholera, diarrhea, and oral rehydration therapy: triumph and indictment

Cholera drove the sanitary revolution in the industrialized world in the 19th century and now is driving the development of oral rehydration therapy (ORT) in the developing world. Despite the long history of cholera, only in the 1960s and 1970s was ORT fully developed. Scientists described this treatment after the discovery of the intact sodium-glucose intestinal cotransport in patients with cholera. This new understanding sparked clinical studies that revealed the ability of ORT to reduce the mortality associated with acute diarrheal disease. Despite the steady reductions in mortality due to acute dehydrating diarrheal diseases achieved by ORT, the costly morbidity due to these diseases remains, the result of a failure to globalize sanitation and to control the developmental impact of diarrheal diseases and their associated malnutrition. New advances in oral rehydration and nutrition therapy and new methods to recognize its costs are discussed in this review.

Street Children, Human Rights, and Public Health: A Critique and Future Directions

▪ Abstract  This review presents a critique of the academic and welfare literature on street children in developing countries, with supporting evidence from studies of homelessness in industrialized nations. The turn of the twenty-first century has seen a sea change of perspective in studies concerning street youth. This review examines five stark criticisms of the category “street child” and of research that focuses on the identifying characteristics of a street lifestyle rather than on the children themselves and the depth or diversity of their actual experiences. Second, it relates the change of approach to a powerful human rights discourse—the legal and conceptual framework provided by the United Nations Convention on the Rights of the Child—which emphasizes children's rights as citizens and recognizes their capabilities to enact change in their own lives. Finally, this article examines literature focusing specifically on the risks to health associated with street or homeless lifestyles. Risk assessment that assigns street children to a category “at risk” should not overshadow helpful analytical approaches focusing on children's resiliency and long-term career life prospects. This review thus highlights some of the challenging academic and practical questions that have been raised regarding current understandings of street children.