Early life stress (ELS) is defined as an acute or chronic stressor that negatively impacts a child's development. ELS is associated with substance use and mental health problems. This narrative literature review focuses on sex and gender differences in the effects of ELS on 1) adolescent neuroendocrine development; 2) pubertal brain maturation; and 3) development of internalizing symptoms and subsequent substance use. We posit that ELS may generate larger hormonal dysregulation in females than males during puberty, increasing internalizing symptoms and substance use. Future research should consider sex and gender differences in neuroendocrine developmental processes when studying the link between ELS and negative health outcomes.
Alexandra Donovan, Shervin Assari, Christine E. Grella et al.
BACKGROUND: Although early life factors are associated with increased suicide risk in youth, there is a dearth of research on these associations for individuals growing up in disadvantaged socioeconomic contexts, particularly in low- and middle-income countries (LMICs). We documented the association between individual, familial, and environmental factors in childhood with suicidal ideation among South African youth. METHODS AND FINDINGS: We used data from 2,020 participants in the Birth to Twenty Plus (Bt20+) study, a South African cohort following children born in Soweto, Johannesburg from birth (1990) to age 28 years (2018). Suicidal ideation was self-reported at ages 14, 17, 22, and 28 years, and the primary outcome of interest was suicidal ideation reported at any age. We assessed individual, familial, and socioeconomic characteristics at childbirth and during infancy, adverse childhood experiences (ACEs) between ages 5 and 13 years, and externalizing and internalizing problems between 5 and 10 years. We estimated odds ratios (ORs) of suicidal ideation for individuals exposed to selected childhood factors using logistic regression. Lifetime suicidal ideation was reported by 469 (23.2%) participants, with a 1.7:1 female/male ratio. Suicidal ideation rates peaked at age 17 and decreased thereafter. Socioeconomic adversity, low birth weight, higher birth order (i.e., increase in the order of birth in the family: first, second, third, fourth, or later born child), ACEs, and childhood externalizing problems were associated with suicidal ideation, differently patterned among males and females. Socioeconomic adversity (OR 1.13, CI 1.01 to 1.27, P = 0.031) was significantly associated with suicidal ideation among males only, while birth weight (OR 1.20, CI 1.02 to 1.41, P = 0.03), ACEs (OR 1.11, CI 1.01 to 1.21, P = 0.030), and higher birth order (OR 1.15, CI 1.07 to 1.243, P < 0.001) were significantly associated with suicidal ideation among females only. Externalizing problems in childhood were significantly associated with suicidal ideation among both males (OR 1.23, 1.08 to 1.40, P = 0.002) and females (OR 1.16, CI 1.03 to 1.30, P = 0.011). Main limitations of the study are the high attrition rate (62% of the original sample was included in this analysis) and the heterogeneity in the measurements of suicidal ideation. CONCLUSIONS: In this study from South Africa, we observed that early life social and environmental adversities as well as childhood externalizing problems are associated with increased risk of suicidal ideation during adolescence and early adulthood.
Massimiliano Orri, Marilyn N. Ahun, Sara Naomi Naicker et al.
contributed to its extreme levels of inequality. Twenty-five years after the transition to democracy, socio-economic and health inequalities continue to rank among the highest in the world. The Birth to Twenty+ study follows a cohort born in urban Johannesburg in 1990 through their early lives and into young adulthood. Also known as 'Mandela's Children', these 'children of the '90s' were the first generation to be raised in a democratic society, whose elected government implemented policies to achieve greater socio-economic and health equality. Correlating early life outcomes to those of their parents provides a baseline estimate of intergenerational transmission of historical inequality. Analyses of their early life course indicates the potential breakdown in inequality in the first generation. This paper provides an overview of empirical results on intergenerational change in socio-economic status and health during South Africa's political transition. Access to infrastructural services improved, and poverty reduced following the rapid expansion of unconditional cash transfers mainly to children and pensioners. However, unemployment remained high and job discrimination continued. Inequalities in health follow similar patterns, and progress did not equate to convergence. Some catch-up physical growth occurred-both across groups and over time-but not sufficient to bridge cognitive inequalities. Socio-economic and health inequalities continued as the children of the '90s reached young adulthood. Based on knowledge of other transitions, it is likely that these inequalities will only start to break down in later generations, provided social and economic progress holds steady.
BACKGROUND: Early initiation of breast feeding (EIBF) reduces the risk of neonatal mortality. However, only 45% of newborns are breast-fed within the first hour after birth and prelacteal feeding (PLF) is widely prevalent in low- and middle-income countries (LMICs). OBJECTIVE: To assess within- and between-country disparities in EIBF and PLF practices by household wealth and place of birth and to investigate the national-level correlation between these feeding indicators in LMICs. METHODS: Data from Demographic Health Surveys and Multiple Indicator Cluster Surveys (2010-2019) in 76 LMICs were used to investigate within-country disparities in EIBF, any PLF, milk-based prelacteal feeding (MPLF), and water-based prelacteal feeding (WPLF) by wealth quintiles and place of childbirth (institutional [private or public sector] or in-home) for children under two years. We examined the between-country Pearson's correlation between EIBF and types of PLF, later adjusted for per capita gross domestic product (GDP). RESULTS: No clear wealth-related differences were found for EIBF and WPLF; however, any PLF and MPLF were significantly higher in children belonging to the richest 20% of households but are also prevalent among lower income groups. Prevalence of any PLF was higher among institutional births in all LMICs, but especially for MPLF in private sector deliveries in East Asia & the Pacific, Eastern Europe & Central Asia, and Latin America & the Caribbean. WPLF was more common in all African regions. EIBF was inversely correlated with any PLF (r = -0.59, 95% CI -0.72, -0.42), MPLF (r = -0.41, 95% CI -0.58, -0.21) and WPLF (r = -0.34, 95% CI -0.53, -0.13). Adjustment for log-GDP did not affect the magnitude and direction of the results. CONCLUSION: Clear prorich disparities exist in the prevalence of PLF, especially MPLF. Children born in private sector facilities are more likely to receive MPLF. EIBF is negatively associated with PLF practices in LMICs. The promotion of better early feeding practices is urgent to achieve the Sustainable Development Goal to reduce neonatal mortality to 12 deaths per 1000 live births.
Paulo Augusto Ribeiro Neves, Juliana dos Santos Vaz, Luiza Isnardi Cardoso Ricardo et al.
A recent Nature article modelled within-country inequalities in primary, secondary, and tertiary education and forecast progress towards Sustainable Development Goal (SDG) targets related to education (SDG 4). However, their paper entirely overlooks inequalities in achieving Target 4.2, which aims to achieve universal access to quality early childhood development, care and preschool education by 2030. This is an important omission because of the substantial brain, cognitive and socioemotional developments that occur in early life and because of increasing evidence of early-life learning's large impacts on subsequent education and lifetime wellbeing. We provide an overview of this evidence and use new analyses to illustrate medium- and long-term implications of early learning, first by presenting associations between pre-primary programme participation and adolescent mathematics and science test scores in 73 countries and secondly, by estimating the costs of inaction (not making pre-primary programmes universal) in terms of forgone lifetime earnings in 134 countries. We find considerable losses, comparable to or greater than current governmental expenditures on all education (as percentages of GDP), particularly in low- and lower-middle-income countries. In addition to improving primary, secondary and tertiary schooling, we conclude that to attain SDG 4 and reduce inequalities in a post-COVID era, it is essential to prioritize quality early childhood care and education, including adopting policies that support families to promote early learning and their children's education.
Linda Richter, Jere Richard Behrman, Pia Rebello Britto et al.
PURPOSE: We investigated associations between adolescent internalizing and externalizing problems and adult human capital in a non-Western setting. Little is known about adolescent mental health problems and adult outcomes in low- and middle-income countries, many of which are characterized by high levels of adversities. METHODS: Data came from the Birth to Twenty Plus cohort, started in Soweto, Johannesburg, South Africa, in 1990. We estimated associations of internalizing and externalizing problems at the age of 14 years with self-reported educational, employment, welfare receipt, psychosocial (psychological distress, criminality, substance use), interpersonal (social isolation, intimate partner violence, partnership status), and HIV outcomes at the age of 28 years. RESULTS: Adolescents with high internalizing problems were less likely to have completed secondary school or be formally employed and more likely to report psychological distress. Those with high levels of externalizing problems were more likely to report adulthood criminal activity and substance use. We found significant associations between internalizing and externalizing problems and intimate partner violence. There was no association between adolescent mental health problems and welfare receipt, HIV, social isolation, or partnership status. Men were more likely to report incomplete secondary education, no formal employment, criminality and substance use, social isolation, and no serious relationship, whereas women were more likely to experience psychological distress and be in receipt of welfare. CONCLUSIONS: Adolescent mental health problems are associated with long-term negative adult functioning under varying socioeconomic conditions. Interventions to recognize and address youth mental health problems in low- and middle-income countries are needed to avert serious adverse adult and societal consequences.
Linda Richter, Marilyn N. Ahun, Sahba Nomvula Besharati et al.
PURPOSE: In high-income countries, early and rapid pubertal development is consistently associated with poor adjustment and increased risk behavior in adolescence. This study contributes to the meager knowledge of these associations in lower income countries. METHODS: We used longitudinal data from 1,784 urban black South Africans in the Birth to Twenty Plus cohort. We used regression analyses to assess associations between age at menarche and latent classes of pubertal timing and tempo and adolescent internalizing and externalizing emotional and behavioral problems, eating attitudes, and patterns of health risk behavior initiation. RESULTS: Relatively earlier and faster pubertal timing and tempo were associated with increased health risk behavior initiation (e.g., adjusted odds ratio [95% confidence interval] high- vs. low-risk pattern = 5.7 [1.7, 19.06] for male genital development; adjusted odds ratio = 3.45 [1.13, 10.49] for female breast development). Among males, earlier and faster pubertal timing and tempo were associated with increased externalizing problems in early adolescence and increased oppositional defiant problems in midadolescence, whereas later and slower pubertal timing and tempo were associated with decreases. Among females, earlier and faster pubertal timing and tempo were associated with increased internalizing and externalizing problems in midadolescence and increased dieting behaviors in early and late adolescence (β [95% confidence interval] = 2.51 [.87, 4.15] for pubic hair development), whereas later and slower pubertal timing and tempo were associated with decreases. CONCLUSIONS: In this urban South African cohort, relatively earlier and faster pubertal development was detrimental to mental health and risk behavior activity, whereas later and slower maturation was somewhat protective.
Alysse J. Kowalski, O. Yaw Addo, Michael R. Kramer et al.
Background: Growth faltering has been associated with poor intellectual performance.The relative strengths of associations between growth in early and in later childhood remain underexplored.Objectives: We examined the association between growth in childhood and adult human capital in 5 low-and middleincome countries (LMICs). Methods:We analyzed data from 9503 participants in 6 prospective birth cohorts from 5 LMICs (Brazil, Guatemala, India, the Philippines, and South Africa).We used linear and quasi-Poisson regression models to assess the associations between measures of height and relative weight at 4 age intervals [birth, age ∼2 y, midchildhood (MC), adulthood] and 2 dimensions of adult human capital [schooling attainment and Intelligence Quotient (IQ)].Results: Meta-analysis of site-and sex-specific estimates showed statistically significant associations between size at birth and height at ∼2 y and the 2 outcomes (P < 0.001).Weight and length at birth and linear growth from birth to ∼2 y of age (1 z-score difference) were positively associated with schooling attainment (β: 0.13; 95% CI: 0.08, 0.19, β: 0.17; 95% CI: 0.07, 0.32, and β: 0.25, 95% CI: 0.10, 0.40, respectively) and adult IQ (β: 0.74, 95% CI: 0.35, 1.14, β: 0.73, 95% CI: 0.35, 1.10, and β: 1.52, 95% CI: 0.96, 2.08, respectively).Linear growth from age 2 y to MC and from MC to adulthood was not associated with higher school attainment or IQ.Change in relative weight in early childhood, MC, and adulthood was not associated with either outcome.Conclusions: Linear growth in the first 1000 d is a predictor of schooling attainment and IQ in adulthood in LMICs.Linear growth in later periods was not associated with either of these outcomes.Changes in relative weight across the life course were not associated with schooling and IQ in adulthood.
Natalia Elvira Poveda, Fernando Pires Hartwig, Cesar Gomes Victora et al.
Background: Early feeding practices are important determinants of optimal feeding patterns later in life. We aimed to investigate if giving any fluids or foods other than breast milk during the first three days after birth (prelacteal feeds) affects exclusive breastfeeding and consumption of formula among children under six months of age in low and middle-income countries (LMICs). Methods: We conducted a retrospective cohort study using data from 85 nationally representative Demographic Health Surveys (DHS) and Multiple Indicator Cluster Surveys (MICS) in LMICs (2010-2019). We considered three exposures: any prelacteal feeding (PLF), milk-based only prelacteal feeding (MLK), and water-based only prelacteal feeding (WTR), according to the DHS/MICS definition. The outcomes were exclusive breastfeeding, based on the World Health Organization definition, and consumption of formula among infants under six months of age. We used Poisson models adjusting for sociodemographic indicators, antenatal care, birth assistance, and early initiation of breastfeeding to estimate the effects of the exposures on the outcomes. Findings were grouped by each country, as well as by regions of the world and national income classification. Results: We included data from 91 282 children. PLF, MLK, and WTR had a prevalence of 33.9% (95% confidence interval (CI) = 33.6-34.2), 22.2% (95% CI = 21.9-22.4), and 9.4% (95% CI = 9.2-9.6), respectively. Exclusive breastfeeding and consumption of formula had a prevalence of 35.2% (95% CI = 34.9-35.5) and 27.7% (95% CI = 27.4-28.0), respectively. In the crude analysis, children who were given PLF were 40% less likely to be exclusively breastfed (prevalence ratio (PR) = 0.60; 95% CI = 0.56-0.64) and nearly twice more likely to receive formula (PR = 1.89; 95% CI = 1.72-2.08); the direction of the associations was the same across income groups and regions of the world. In the adjusted analysis, the observed crude effects were only slightly reduced (exclusive breastfeeding - PR = 0.62; 95% CI = 0.59-0.66, consumption of formula - PR = 1.72; 95% CI = 1.59-1.85). MLK showed a stronger impact on the outcomes than PLF, especially for formula consumption (adjusted PR = 1.81; 95% CI = 1.67-1.97) and in low-income countries. WTR was only negatively associated with exclusive breastfeeding (adjusted PR = 0.69; 95% CI = 0.63-0.75), but not with formula consumption (adjusted PR = 1.09; 95% CI = 0.99-1.20). Conclusions: Feeding babies prelacteal foods shortens exclusive breastfeeding duration and increases the likelihood of formula consumption in children under six months of age in LMICs. Pro-breastfeeding interventions must be prioritized during antenatal care and throughout the stay in the maternity facility to properly protect, support, and promote exclusive breastfeeding since birth.
Paulo Augusto Ribeiro Neves, Nancy Armenta-Paulino, Luisa Arroyave et al.
BACKGROUND: Nutrition is important for growth and brain development and therefore cognitive ability. Growth faltering in early childhood, an important indicator of early adversity, is associated with poorer developmental outcomes, some into adulthood, but this association probably reflects early-life deprivation. We aimed to investigate the associations between early-life stature, child IQ, and adult IQ. METHODS: In this cohort study, we used prospective longitudinal data collected in four birth cohorts from Brazil (born in 1993), Guatemala (born in 1969-77), the Philippines (born in 1983-84), and South Africa (born in 1990). Using multivariable linear models, we estimated the relative contributions of early-life stature, child IQ, and schooling (highest school year completed) to adult IQ, including interaction effects among the early-childhood measures and schooling. FINDINGS: We included 2614 individuals in the analysis. Early-life stature was associated with adult IQ (range across eight site-by-sex groups -0·14 to 3·17 IQ points) and schooling (-0·05 to 0·77 years) per height-for-age Z-score. These associations were attenuated when controlling for child IQ (-0·86 to 1·72 for adult IQ and -0·5 to 0·60 for schooling). The association of early-life stature with adult IQ was further attenuated when controlling for schooling (-1·86 to 1·21). Child IQ was associated with adult IQ (range 3·91 to 10·02 points) and schooling (0·25 to 1·30 years) per SD of child IQ in all groups; these associations were unattenuated by the addition of early-life stature to the models. The interaction between schooling and child IQ, but not that between schooling and early-life stature, was positively associated with adult IQ across groups. INTERPRETATION: The observed associations of early-life stature with adult IQ and schooling varied across cohorts and sexes and explained little variance in adult IQ beyond that explained by child IQ. These findings suggest that interventions targeted at growth for health and early development are important. Our results are consistent with the inference that improving long-term cognitive outcomes might require interventions that more specifically target early cognitive ability. FUNDING: Bill & Melinda Gates Foundation.
Aryeh D. Stein, Linda S. Adair, Georgina Donati et al.
