Childhood adversity during the post-apartheid transition and COVID-19 stress independently predict adult PTSD risk in urban South Africa: A biocultural analysis of the stress sensitization hypothesis.

OBJECTIVES: The COVID-19 pandemic in South Africa introduced new societal adversities and mental health threats in a country where one in three individuals are expected to develop a psychiatric condition sometime in their life. Scientists have suggested that psychosocial stress and trauma during childhood may increase one's vulnerability to the mental health consequences of future stressors-a process known as stress sensitization. This prospective analysis assessed whether childhood adversity experienced among South African children across the first 18 years of life, coinciding with the post-apartheid transition, exacerbates the mental health impacts of psychosocial stress experienced during the 2019 coronavirus (COVID-19) pandemic (ca. 2020-2021). MATERIALS AND METHODS: Data came from 88 adults who participated in a follow-up study of a longitudinal birth cohort study in Soweto, South Africa. Childhood adversity and COVID-19 psychosocial stress were assessed as primary predictors of adult PTSD risk, and an interaction term between childhood adversity and COVID-19 stress was calculated to evaluate the potential effect of stress sensitization. RESULTS: Fifty-six percent of adults exhibited moderate-to-severe PTSD symptoms. Greater childhood adversity and higher COVID-19 psychosocial stress independently predicted worse post-traumatic stress disorder symptoms in adults. Adults who reported greater childhood adversity exhibited non-significantly worse PTSD symptoms from COVID-19 psychosocial stress. DISCUSSION: These results highlight the deleterious mental health effects of both childhood trauma and COVID-19 psychosocial stress in our sample and emphasize the need for greater and more accessible mental health support as the pandemic progresses in South Africa.

Infection, nutritional status, and body composition: Associations at birth and 6 months postnatally in Soweto, South Africa.

INTRODUCTION: The impact of infection on infant nutritional status, body size, and growth is well documented. However, research into the impact of infection on infant body composition is limited. Greater understanding is, therefore, needed on the effects of infection in early life. METHODS: Associations between a composite morbidity index consisting of the sum of the cumulative tallies for a range of symptoms representing infection and morbidity in the infants and nutritional status (height-for-age (HAZ), and weight-for-height (WHZ)), and body composition (fat-free mass (FFM), fat mass (FM), fat-free mass index (FFMI), and fat mass index (FMI)) at 6 months of age were investigated using hierarchical regression analysis. RESULTS: The sample comprised data between birth and 6 months postnatally, of 156 infants who were a priori born healthy in Soweto, South Africa. Morbidity, over the cumulative period of birth to 6 months, was associated with lower FMI (ß = -1.77) and lower FM (ß = -0.61), and conversely with higher FFM (ß = 0.94), in infants at 6 months. No associations were found between the morbidity index and FFMI, HAZ, and WHZ. Increased birthweight was associated with a higher FFM (ß = 0.66), HAZ (ß = 1.14), and WHZ (ß = 0.87). Finally, safely managed sanitation facilities, representative of reduced environmental exposure to fecal-oral transmission pathways were associated with a higher HAZ (ß = 1.21). DISCUSSION: Reduction in FMI and FM and exposure to inflammatory cytokines associated with mounting an immune response could alter phenotypic trajectories during to this period of plasticity. From a public health perspective, these results imply that it is important to intensify efforts to prevent infection in infants in the first 6 months postnatally, and that these efforts should concentrate on access to safely managed sanitation facilities.

Psychological legacies of intergenerational trauma under South African apartheid: Prenatal stress predicts greater vulnerability to the psychological impacts of future stress exposure during late adolescence and early adulthood in Soweto, South Africa.

BACKGROUND: South Africa's rates of psychiatric morbidity are among the highest in sub-Saharan Africa and are foregrounded by the country's long history of political violence during apartheid. Growing evidence suggests that in utero stress exposure is a potent developmental risk factor for future mental illness risk, yet the extent to which the psychiatric effects of prenatal stress impact the next generation are unknown. We evaluate the intergenerational effects of prenatal stress experienced during apartheid on psychiatric morbidity among children at ages 17-18 and also assess the moderating effects of maternal age, social support, and past household adversity. METHODS: Participants come from Birth-to-Twenty, a longitudinal birth cohort study in Soweto-Johannesburg, South Africa's largest peri-urban township which was the epicentre of violent repression and resistance during the final years of the apartheid regime. Pregnant women were prospectively enrolled in 1990 and completed questionnaires assessing social experiences, and their children's psychiatric morbidity were assessed at ages 17-18. RESULTS: Full data were available from 304 mother-child pairs in 2007-8. Maternal prenatal stress in 1990 was not directly associated greater psychiatric morbidity during at ages 17-18. Maternal age and past household adversity moderated the intergenerational mental health effects of prenatal stress such that children born to younger mothers and late adolescent/young adult children experiencing greater household adversity exhibited worse psychiatric morbidity at ages 17-18. Social support did not buffer against the long-term psychiatric impacts of prenatal stress. CONCLUSIONS: Greater prenatal stress from apartheid predicted adverse psychiatric outcomes among children born to younger mothers and adolescents/young adults who experienced greater concurrent stress. Our findings suggest that prenatal stress may affect adolescent mental health, have stress-sensitising effects, and represent possible intergenerational effects of trauma experienced under apartheid in this sample.

The Healthy Aging Adult South Africa report card: a systematic review of the evidence between 2013 and 2020 for middle-aged South African men and women.

Due to the increasing non-communicable disease burden in Africa, several strategies that target the major lifestyle and physiological risk factors have been implemented to combat such diseases. The Healthy Aging Adult South Africa report card systematically reviews national and regional prevalence data of middle-aged South African adults (45-65 years) published between 2013 and 2020 on diet, physical activity, tobacco use and alcohol consumption, obesity, hypertension, dyslipidaemia and diabetes mellitus. Each indicator was assigned two grades, (1) based on the availability of prevalence data, and (2) based on whether policies have been proposed and implemented for the respective indicators. Alcohol consumption, obesity, hypertension and diabetes received an A grade for the availability of prevalence data. Tobacco use and diet received an A grade for policy and implementation. Gaps have been identified that need to be filled by future research focusing on continued surveillance of all indicators in order to inform and implement effective policies.

Direct and Indirect Determinants of Body Mass Index in Both Major Ethnic Groups Experiencing the Nutritional Transition in Cameroon.

In the context of rapid nutritional transitions in Africa, few studies have analyzed the etiology of obesity by considering the driver pathways that predict body mass index (BMI). The aim of this study is to innovatively identify these driver pathways, including the main sociodemographic and socioecological drivers of BMI. We conducted a rural-urban quantitative study in Cameroon (n = 1106; balanced sex ratio) to explore this issue. We recruited participants and reported several sociodemographic characteristics (e.g., marital status, socioeconomic status (SES), and ethnicity). We then assessed three main socioecological drivers of BMI (body weight perception, dietary intake, and physical activity) and conducted bioanthropometric measurements. We identified several driver pathways predicting BMI. In Cameroon, Bamiléké ethnicity, higher SES, being married, and older age had positive effects on BMI through overweight valorization and/or dietary intake. Accordingly, we found that being Bamiléké, married, and middle-aged, as well as having a higher SES, were factors that constituted at-risk subgroups overexposed to drivers of obesity. As such, this study highlights the necessity of investigating the complex driver pathways that lead to obesity. Therefore, better identification of the subgroups at risk for obesity will help in developing more targeted population health policies in countries where this burden is a major public health issue.

Rethinking water, sanitation, and hygiene for human growth and development.

Life history theory emphasises plasticity in developmental and biological programming where conditions in early life, lead to long-term consequences for health and wellbeing. Studies linking water, sanitation, and hygiene, nutrition, and child growth and development have emphasised the optimisation of linear growth as a key metric for the evaluation of intervention efficacy. Life history characteristics pertaining to human growth and phenotypic plasticity, suggest that different developmental outcomes in early childhood may be responsive to different stimuli at different ages. Energy utilisation by the human brain, from birth through childhood, accounts for a disproportionate percentage of the resting metabolic rate. Undernutrition in early life, and its relative resultant energy deficiency, may trigger adaptive physiological mechanisms prioritising brain growth at the expense of body growth. Emphasis placed on linear growth may have impeded the significance of WASH due to excluding aspects of child development beyond height/weight. We propose that incorporating evolutionary public health and life history theory perspectives, allows for the identification of age-appropriate biological outcomes and WASH indicators, while anticipating the timing and life-course suitability of the interventions being operationalised. Finally, integrating reflections regarding context allows for the development of transformative WASH interventions.

Determinants of energy intake in Central African populations experiencing nutrition transition.

Central Africa is experiencing rapid urbanisation, and this situation comes along with changes in food habits and an increased prevalence of obesity and associated health risks. Factors influencing dietary intake among the diverse African populations are not well understood. Our objective was to characterise the dietary intake and their determinants in the two main ethnic groups experiencing nutrition transition in Cameroon, the Bamiléké and the Béti. We sampled Bamiléké (381) and Béti (347) adults living in both rural and urban, collected socio-demographic variables, assessed dietary patterns by using a food portion photographs book to administrate a FFQ and a 24-h dietary recall technique and derived their BMI from measured weight and height. The dietary patterns of Bamiléké people were composed of more energy-dense foods than the Béti people, regardless of the living area. The energy intake (13·8 (sd 4·6)-15·4 (sd 4·8) MJ v. 9·7 (sd 3·5)-11·2 (sd 3·9 MJ) and the obesity (15-29 % v. 5-8 %) were therefore higher in Bamiléké than in Béti, respectively. Multivariable linear regression analyses showed strong associations of both ethnicities (4·02 MJ; P < 0·001), living area (0·21 MJ; P < 0·001) and education (0·59 MJ; P < 0·048) with energy intake, independently of each other and other socio-demographic factors. The ethnicity factor has been characterised as the more important determinant of diet. Our findings provide new insights and perspectives highlighting the importance of anthropological factors when building prevention campaigns against obesity in Central Africa.

Advocating for a Collaborative Research Approach on Transgenerational Transmission of Trauma.

Since Myers (1915) coined the term 'shell shock' to define the prolonged suffering of soldiers returning from the Great War, the psychological and physical result of distressing experiences, known as trauma, has been of academic interest. Transgenerational transmission of trauma effects has been recorded, demonstrating that on some level, the exposure to trauma of one generation can impact individuals of a subsequent generation (Yehuda & Lehrner, 2018). Observational studies on children of holocaust survivors formed the basis of this trajectory of research (Rakoff, 1966), and eventually this phenomenon became referred to as the transgenerational transmission of trauma (TTT). Since then, TTT has been observed in several contexts, including within families who have experienced high rates historical trauma (O'Neill et al., 2016), within regions high-frequencies of historical war and terrorism (Yehuda & Lehrner, 2018) and those who have undergone famine (Ahmed, 2010). This report aims to outline several pathways (biological, psychological, and sociological) by which trauma may be transmitted across generations. Moreover, it discusses several methods of trauma assessment and the related challenges and benefits. Lastly, this report advocates a biopsychosocial approach - an interdisciplinary model using the interplay of biological, psychological, and social-environmental factors - to research TTT. By promoting the benefits of such an interdisciplinary approach we attempt to break up silos between disciplines and encourage collaboration between academics from various backgrounds researching this topic to better serve individuals impacted by TTT.

Association Between Household and Maternal Socioeconomic Factors with Birth Outcomes in the Democratic Republic of Congo and South Africa: A Comparative Study.

OBJECTIVE: To assess and compare the associations between household socioeconomic (SES) factors with birth outcomes (low birth weight (LBW), small-for-gestational age (SGA) and preterm birth (PTB)) in the Democratic Republic of Congo (DRC) and South Africa (SA). METHODS: Cross-sectional data of mother-newborn pairs collected in 2017 in the DRC were compared with mother-newborn pairs data from the SA Soweto first 1000-days pregnancy cohort study (2013-2016). Country-specific and pooled multivariable logistic regressions analyses assessed the associations between maternal education, marital status, and housing with LBW, SGA, and PTB adjusted for maternal anthropometry and obstetric factors. RESULTS: 1084 mother-newborn pairs were recruited (DRC: 256; SA: 828). The rates of LBW, PTB and SGA were, 11.5%, 17.1% and 32.8% in the DRC and 15.9%, 10.5% and 20.1% in SA. SES factors differed between countries and sex. In the DRC, being married decreased the odds of having LBW and PTB children by 86% and 80%, respectively. In SA, being a mother with secondary level of education and above was associated with 86% reduced odds of SGA. In the pooled analyses, women with secondary level of education and above had a 2.2-fold increase in odds of giving birth to a PTB newborn. Country of residence and maternal nutritional status were stronger predictors of birth outcomes than SES factors. CONCLUSION FOR PRACTICE: In sub-Saharan Africa, policies aiming to alleviate women's education combined with improved social support and household SES prior to and during pregnancy are critical to optimal neonatal outcomes and strategic to achieve the Sustainable Development Goals.

Understanding how maternal social and biological factors are related to fetal growth in an urban South African cohort.

The aim of this study was to identify social and biological drivers of fetal growth by examining associations with household, preconception, and pregnancy factors in a cohort from Soweto, South Africa. Complete data and ultrasound scans were collected on 519 women between 2013 and 2016 at 6 time points during pregnancy (<14, 14-18, 19-23, 24-28, 29-33 weeks, and 34-38 weeks). Household-level factors, preconception health, baseline body mass index (BMI), and demographic data were collected at the first visit. During pregnancy, gestational weight gain (GWG; kg/week) was calculated. At 24-28 weeks of gestation, oral glucose tolerance test was used to determine gestational diabetes mellitus (GDM) status, and hypertension status was characterised. Longitudinal growth in head circumference, abdominal circumference, biparietal diameter, and femur length were modelled using the Superimposition by Translation and Rotation, a shape-invariant model which produces growth curves against gestational age. A priori identified exposure variables were then included in a series of sex-stratified hierarchical regression models for each fetal growth outcome. No household-level factors were associated with fetal growth. Maternal BMI at baseline was positively associated with all outcome parameters in males and females. Both GWG (in males and females) and GDM (in males) were significant positive predictors of abdominal growth. Males showed more responsiveness to abdominal growth, while females were more responsive to linear growth. Thus, fetal growth was largely predicted by maternal biological factors, and sexual dimorphism in the responsiveness of fetal biometry to biological exposures was evident.

Stunting in infancy, pubertal trajectories and adult body composition: the Birth to Twenty Plus cohort, South Africa.

BACKGROUND/OBJECTIVES: Childhood rapid growth and earlier puberty onset have been associated with adult obesity. However, the association between childhood stunting, pubertal timing and adult obesity is unclear. We examined whether the relationship between stunting at age 2 years (y) and body composition at 23 years is mediated by adolescent body mass index, and pubertal development, using the Birth-to-Twenty Plus cohort (South Africa). SUBJECTS/METHODS: For 1036 participants, data on anthropometrics between birth and 23 years, maternal factors, and pubertal development (Tanner scale at 9-16 years) were collected. Stunting at 2 years (height-for-age z-score < -2), 5-18 years BMI-for-age trajectories, pubertal development trajectories, and DXA-derived fat mass (FM) and fat free mass (FFM) at 23 years were determined. Data were analysed using hierarchical regressions and structural equation models. RESULTS: Stunting was directly associated with slower pubertal development and with shorter adult stature, but was not associated with adolescent BMI trajectories, adult FM or FFM. However, stunting was indirectly associated with adult FM and FFM through the direct associations between slower pubertal development and lower FM and between shorter height and lower FFM. BMI trajectories were independently associated with FM and FFM. CONCLUSIONS: Being stunted in this population predicted adult body composition through slower pubertal development and shorter adult stature.

Response of the human gut and saliva microbiome to urbanization in Cameroon.

Urban populations from highly industrialized countries are characterized by a lower gut bacterial diversity as well as by changes in composition compared to rural populations from less industrialized countries. To unveil the mechanisms and factors leading to this diversity loss, it is necessary to identify the factors associated with urbanization-induced shifts at a smaller geographical scale, especially in less industrialized countries. To do so, we investigated potential associations between a variety of dietary, medical, parasitological and socio-cultural factors and the gut and saliva microbiomes of 147 individuals from three populations along an urbanization gradient in Cameroon. We found that the presence of Entamoeba sp., a commensal gut protozoan, followed by stool consistency, were major determinants of the gut microbiome diversity and composition. Interestingly, urban individuals have retained most of their gut eukaryotic and bacterial diversity despite significant changes in diet compared to the rural areas, suggesting that the loss of bacterial microbiome diversity observed in industrialized areas is likely associated with medication. Finally, we observed a weak positive correlation between the gut and the saliva microbiome diversity and composition, even though the saliva microbiome is mainly shaped by habitat-related factors.

Early-life exposures and cardiovascular disease risk among Ghanaian migrant and home populations: the RODAM study.

Early-life environmental and nutritional exposures are considered to contribute to the differences in cardiovascular disease (CVD) burden. Among sub-Saharan African populations, the association between markers of early-life exposures such as leg length and sitting height and CVD risk is yet to be investigated. This study assessed the association between leg length, sitting height, and estimated 10-year atherosclerotic cardiovascular disease (ASCVD) risk among Ghanaian-born populations in Europe and Ghana. We constructed sex-specific quintiles for sitting height and leg length for 3250 participants aged 40-70 years (mean age 52 years; men 39.6%; women 60.4%) in the cross-sectional multicenter Research on Diabetes and Obesity among African Migrants study. Ten-year risk of ASCVD was estimated using the Pooled Cohort Equations; risk ≥7.5% was defined as "elevated" CVD risk. Prevalence ratios (PR) were estimated to determine the associations between sitting height, leg length, and estimated 10-year ASCVD risk. For both men and women, mean sitting height and leg length were highest in Europe and lowest in rural Ghana. Sitting height was inversely associated with 10-year ASCVD risk among all women (PR for 1 standard deviation increase of sitting height: 0.75; 95% confidence interval: 0.67, 0.85). Among men, an inverse association between sitting height and 10-year ASCVD risk was significant on adjustment for study site, adult, and parental education but attenuated when further adjusted for height. No association was found between leg length and estimated 10-year ASCVD risk. Early-life and childhood exposures that influence sitting height could be the important determinants of ASCVD risk in this adult population.

Assessment of environmental exposure factors on child diarrhea and systemic inflammation in the Eastern Cape.

Poor environmental technologies and gastrointestinal illnesses have been hypothesized to be a primary cause to the lack of impact of child health programs on child stunting rates (low height-for-age) in South Africa. This study assessed correlations between environmental exposures (water source, water treatment, sanitation, refuse), diarrheal occurrences, and systemic inflammation proxies among female and male children under five years of age in the Eastern Cape. A conceptual model was hypothesized using structural equation (SE) modeling and two sex-specific (female and male) datasets were subsequently generated from the data and applied to the hypothesized SE model. Results suggested that environmental exposure variables associated with diarrhea and systemic inflammation proxies were different between females and males. For diarrheal occurrences among females, an increase in local authority management of refuse (compared to household management) (0.161, p-value (p) = 0.007), sharing sanitation facilities (0.060, p = 0.023), and a decrease in the frequency of the treatment of drinking water (-0.043, p = 0.025) were correlated with an increase in diarrhea. For males, an increase in household use of flush toilets (as compared to ventilated pit latrines) was correlated with an increase in diarrhea (0.113, p = 0.027). For systemic inflammation among both sexes, an increase in household use of water pumped into the premises (as compared to a public water tap) and an increase in diarrheal occurrences were correlated with an increase in systemic inflammation. The data support an increased focus on sex and gender specific factors among field practitioners and policy makers working in the environmental health field in South Africa.

The association between household socio-economic status, maternal socio-demographic characteristics and adverse birth and infant growth outcomes in sub-Saharan Africa: a systematic review.

Adverse birth outcomes and infant undernutrition remain the leading causes of morbidity and mortality in sub-Saharan Africa (SSA). Impaired infant growth and development, which often begins during foetal development, may persist during the first 2 years of life and has been associated with higher risks of cardiometabolic diseases. This systematic review assessed the associations between maternal demographic characteristics and household socio-economic status (SES), and preterm birth (PTB), small for gestational age, low birth weight (LBW), stunting, wasting and underweight in children under 2 years of age in SSA countries. Following the Preferred Reporting Items for Systematic reviews and Meta-Analyses guidelines, we searched for publications in three electronic databases (PubMed, Scopus and ScienceDirect). Eleven studies on children under 2 years of age, in four SSA regions, published in English between 1990 and 2018, were included. All the studies were observational in design (cross-sectional or cohort studies). Maternal education was the most commonly explored exposure. Most studies (63.3%) focused on undernutrition during the first 2 years of life: LBW, PTB and stunting. Lower maternal education, maternal unemployment and lower household wealth index were the SES factors most commonly associated with adverse birth outcomes and infant undernutrition. Maternal marital status was not associated with any infant outcomes. The definitions of the SES varied, which may explain discrepancies between studies. Nutrition intervention programs in SSA need to promote education and poverty alleviation in women at reproductive age, starting from pre-pregnancy, to optimise infant growth and development and prevent the increase in the prevalence of cardiometabolic diseases.

Sanitation and diarrhoea in infancy and CRP level at 18 years: the birth-to-twenty plus cohort.

Background: Cardiometabolic disease is associated with chronic low-grade inflammation. While low birthweight, childhood stunting and rapid weight gain predict higher adult high-sensitivity C-reactive protein (hs-CRP) concentrations, associations between childhood infections and adulthood CRP are inconsistent.Aim: To assess the associations between sanitation, diarrhoea and a combined score of both from birth to age 2 years and hs-CRP at age 18 years, independently of early life nutrition and adult adiposity.Subjects and methods: This study collected data on sanitation and diarrhoea episodes from birth to 2 years on 756 participants of the Birth-to-Twenty Plus cohort, a birth cohort initiated in South Africa in 1990, and calculated a combined score of both variables. Anthropometry was measured at 2 years and 18 years and hs-CRP at 18 years.Results: Of the participants, 29.5% had no access to indoor flush sanitation and 38.2% experienced ≥1 diarrhoea episode between birth and 2 years. Not having access to indoor flush sanitation and experiencing ≥1 diarrhoea episodes were associated with 1.50 mg/L and 1.52 mg/L higher hs-CRP, respectively. Prevalence of both burdens in infancy was associated with a 2.18 mg/L higher hs-CRP.Conclusion: In this population, poor sanitation and diarrhoea in early life predict elevated CRP in young adulthood, independently of early life nutrition and adiposity.

Body composition and physical activity as mediators in the relationship between socioeconomic status and blood pressure in young South African women: a structural equation model analysis.

OBJECTIVES: Varying hypertension prevalence across different socioeconomic strata within a population has been well reported. However, the causal factors and pathways across different settings are less clear, especially in sub-Saharan Africa. Therefore, this study aimed to compare blood pressure (BP) levels and investigate the extent to which socioeconomic status (SES) is associated with BP, in rural and urban South Africa women. SETTING: Rural and urban South Africa. DESIGN: Cross-sectional. PARTICIPANTS: Cross-sectional data on SES, total moderate and vigorous physical activity (MVPA), anthropometric and BP were collected on rural (n=509) and urban (n=510) young black women (18-23 years age). Pregnant and mentally or physically disabled women were excluded from the study. RESULTS: The prevalence of combined overweight and obesity (46.5% vs 38.8%) and elevated BP (27.0% vs 9.3%) was higher in urban than rural women, respectively. Results from the structural equation modelling showed significant direct positive effects of body mass index (BMI) on systolic BP (SBP) in rural, urban and pooled datasets. Negative direct effects of SES on SBP and positive total effects of SES on SBP were observed in the rural and pooled datasets, respectively. In rural young women, SES had direct positive effects on BMI and was negatively associated with MVPA in urban and pooled analyses. BMI mediated the positive total effects association between SES and SBP in pooled analyses (ß 0.46; 95% CI 0.15 to 0.76). CONCLUSIONS: Though South Africa is undergoing nutritional and epidemiological transitions, the prevalence of elevated BP still varies between rural and urban young women. The association between SES and SBP varies considerably in economically diverse populations with BMI being the most significant mediator. There is a need to tailor prevention strategies to take into account optimising BMI when designing strategies to reduce future risk of hypertension in young women.

Rural-urban variations in age at menarche, adult height, leg-length and abdominal adiposity in black South African women in transitioning South Africa.

BACKGROUND: The pre-pubertal socioeconomic environment may be an important determinant of age at menarche, adult height, body proportions and adiposity: traits closely linked to adolescent and adult health. AIMS: This study explored differences in age at menarche, adult height, relative leg-length and waist circumference between rural and urban black South African young adult women, who are at different stages of the nutrition and epidemiologic transitions. SUBJECTS AND METHODS: We compared 18-23 year-old black South African women, 482 urban-dwelling from Soweto and 509 from the rural Mpumalanga province. Age at menarche, obstetric history and household socio-demographic and economic information were recorded using interview-administered questionnaires. Height, sitting-height, hip and waist circumference were measured using standardised techniques. RESULTS: Urban and rural black South African women differed in their age at menarche (at ages 12.7 and 14.5 years, respectively). In urban women, a one-year increase in age at menarche was associated with a 0.65 cm and 0.16% increase in height and relative leg-length ratio, respectively. In both settings, earlier age at menarche and shorter relative leg-length were independently associated with an increase in waist circumference. CONCLUSIONS: In black South African women, the earlier onset of puberty, and consequently an earlier growth cessation process, may lead to central fat mass accumulation in adulthood.

The associations between adult body composition and abdominal adiposity outcomes, and relative weight gain and linear growth from birth to age 22 in the Birth to Twenty Plus cohort, South Africa.

BACKGROUND: The growing prevalence of overweight and obesity in low- or middle-income countries precipitates the need to examine early life predictors of adiposity. OBJECTIVES: To examine growth trajectories from birth, and associations with adult body composition in the Birth to Twenty Plus Cohort, Soweto, South Africa. METHODS: Complete data at year 22 was available for 1088 participants (536 males and 537 females). Conditional weight and height indices were generated indicative of relative rate of growth between years 0-2, 2-5, 5-8, 8-18, and 18-22. Whole body composition was measured at year 22 (range 21-25 years) using dual energy x-ray absorptiometry (DXA). Total fat free soft tissue mass (FFSTM), fat mass, and abdominal visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) were recorded. RESULTS: Birth weight was positively associated with FFSTM and fat mass at year 22 (ß = 0.11, p<0.01 and ß = 0.10, p<0.01 respectively). Relative weight gain from birth to year 22 was positively associated with FFSTM, fat mass, VAT, and SAT at year 22. Relative linear growth from birth to year 22 was positively associated with FFSTM at year 22. Relative linear growth from birth to year 2 was positively associated with VAT at year 22. Being born small for gestational age and being stunted at age 2 years were inversely associated with FFSTM at year 22. CONCLUSIONS: The importance of optimal birth weight and growth tempos during early life for later life body composition, and the detrimental effects of pre- and postnatal growth restriction are clear; yet contemporary weight-gain most strongly predicted adult body composition. Thus interventions should target body composition trajectories during childhood and prevent excessive weight gain in early adulthood.

Life History theory hypotheses on child growth: Potential implications for short and long-term child growth, development and health.

Life history theory integrates ecological, physiological, and molecular layers within an evolutionary framework to understand organisms' strategies to optimize survival and reproduction. Two life history hypotheses and their implications for child growth, development, and health (illustrated in the South African context) are reviewed here. One hypothesis suggests that there is an energy trade-off between linear growth and brain growth. Undernutrition in infancy and childhood may trigger adaptive physiological mechanisms prioritizing the brain at the expense of body growth. Another hypothesis is that the period from conception to infancy is a critical window of developmental plasticity of linear growth, the duration of which may vary between and within populations. The transition from infancy to childhood may mark the end of a critical window of opportunity for improving child growth. Both hypotheses emphasize the developmental plasticity of linear growth and the potential determinants of growth variability (including the role of parent-offspring conflict in maternal resources allocation). Implications of these hypotheses in populations with high burdens of undernutrition and infections are discussed. In South Africa, HIV/AIDS during pregnancy (associated with adverse birth outcomes, short duration of breastfeeding, and social consequences) may lead to a shortened window of developmental plasticity of growth. Furthermore, undernutrition and infectious diseases in children living in South Africa, a country undergoing a rapid nutrition transition, may have adverse consequences on individuals' cognitive abilities and risks of cardio-metabolic diseases. Studies are needed to identify physiological mechanisms underlying energy allocation between biological functions and their potential impacts on health.