Frequency and distribution of enamel hypoplasias in a historic skeletal sample

A skeletal sample of 296 individuals from a 19th century American poorhouse cemetery is examined for the frequency and chronological distribution of linear enamel hypoplasias on the mandibular canines and maxillary central incisors. Dental enamel hypoplasias may be considered to be indicators of increased exposure to health risk at the time of weaning. The purpose of this study is to examine childhood stress and provide a relative measure of that stress, as evidenced by hypoplasias, in a historic sample that represents an industrializing population. The frequency of enamel hypoplasias per individual by tooth ranged from 70 to 73%, with a peak age at stress of 2.5 to 3 years for the maxillary central incisor and 3.5 to 4 years for the mandibular canine. There were no significant differences in the presence of hypoplasias between males and females. The peak age at stress between 2.5 and 4 years in this 19th century sample transects the ranges reported for prehistoric populations (2-6 years) and for modern groups (0-3 years). These results indicate that the stress associated with weaning probably occurred earlier in incipient industrial societies than in prehistoric hunter/gatherers and agriculturalists, yet not as early as in modern industrial groups. The high level of childhood stress in this skeletal sample compared with that of other samples may indicate a change in health, at least among the lowest class, associated with the cultural transition from an agricultural to an industrial society.     

Bioarchaeological evidence for adaptive plasticity and constraint: Exploring life‐history trade‐offs in the human past

The Developmental Origins of Health and Disease paradigm evaluates the consequences of early life stress on health at later stages of life. Interacting with this paradigm represents a profound opportunity to leverage the lifespan and contextual approaches to human skeletal remains adopted by bioarchaeological research. Teeth and bone provide evidence for stressors experienced early in life. These events represent evidence for adaptive plasticity as Individuals survive the events through reallocation of energy to essential physiological functions, which inhibits enamel and skeletal growth. Age‐at‐death, adult body size, chronic infection, or childhood mortality may be used as covariates to better understand the physiological constraints operating on individual bodies following survival of early life stress. Contextual evidence from cemeteries provides clues to the ecological and cultural contingencies that exacerbate or mitigate the expression of these trade‐offs. Future studies should incorporate newly derived methods that provide reproducible and precise ways to evaluate early life stress, while incorporating populations that are often neglected.     

Life-history theory, chronic childhood illness and the timing of first reproduction in a British birth cohort

Life-history theoretical models show that a typical evolutionarily optimal response of a juvenile organism to high mortality risk is to reach reproductive maturity earlier. Experimental studies in a range of species suggest the existence of adaptive flexibility in reproductive scheduling to maximize fitness just as life-history theory predicts. In humans, supportive evidence has come from studies comparing neighbourhoods with different mortality rates, historical and cross-cultural data. Here, the prediction is tested in a novel way in a large (n = 9099), longitudinal sample using data comparing age at first reproduction in individuals with and without life-expectancy-reducing chronic disease diagnosed during childhood. Diseases selected for inclusion as chronic illnesses were those unlikely to be significantly affected by shifting allocation of effort away from reproduction towards survival; those which have comparatively large effects on mortality and life expectancy; and those which are not profoundly disabling. The results confirmed the prediction that chronic disease would associate with early age at first reproduction: individuals growing up with a serious chronic disease were 1.6 times more likely to have had a first child by age 30. Analysis of control variables also confirmed past research findings on links between being raised father-absent and early pubertal development and reproduction.     

Differences between Neandertal and modern human infant and child growth models

Studying the emergence of distinctive human growth patterns is essential to understanding the evolution of our species. The large number of Neandertal fossils makes this species the best candidate for a comparative study of growth patterns in archaic and modern humans. Here, Neandertal height growth during infancy and early childhood is described using a mathematical model. Height growth velocities for individuals five years old or younger are modelled as age functions based on different estimates of height and age for a set of ten Neandertal infants and children. The estimated heights of each Neandertal individual are compared with those of two modern human populations based on longitudinal and cross-sectional data. The model highlights differences in growth velocity during infancy (from the age of five months onward). We find that statural growth in Neandertal infants is much slower than that seen in modern humans, Neandertal growth is similar to modern humans at birth, but decreases around the third or fourth month. The markedly slower growth rates of Neandertal infants may be attributable to ontogenetic constraints or to metabolic stress, and contribute to short achieved adult stature relative to modern humans.     

The income body weight gradients in the developing economy of China

Existing theories predict the income gradient of individual body weight to change sign from positive to negative in process of economic development. However, there are only few empirical studies which test this hypothesis. This paper adds to the literature on that topic by investigating the case of China. Using individual and community data from 1991 to 2009 waves of the China Health and Nutrition Survey regression analyses suggest that after controlling for important confounding factors (1) higher income is positively related to future growth of individuals’ BMI in less developed areas (i.e. BMI growth is 0.7–1.5 percentage points higher when comparing the richest with the poorest individuals), but negatively related to BMI growth in more developed areas (i.e. BMI growth is 0.8–1.6 percentage points lower for the richest individuals), and (2) that concentrations of overweight are “trickling down” to lower income ranks as regions become more developed. Moreover, the reversal of the income gradient appears to happen at earlier stages of development for females.     

Family Member Deaths in Childhood Predict Systemic Inflammation in Late Life

Biological and epidemiological evidence has linked early-life psychosocial stress with late-life health, with inflammation as a potential mechanism. We report here the association between familial death in childhood and adulthood and increased levels of high-sensitivity C-reactive protein (CRP), a marker of systemic inflammation. The Cache County Memory Study is a prospective study of persons initially aged 65 and older in 1995. In 2002, there were 1,955 persons in the study with data on CRP (42.3 percent male, mean [SD] age = 81.2 [5.8] years), linked with objective data on family member deaths. Using logistic regression, high (> 10 mg/L) versus low (≤ 10 mg/L) CRP was regressed on cumulative parental, sibling, spouse, and offspring deaths during childhood and during early adulthood, adjusted for family size in each period (percentage family depletion; PFD). Findings revealed PFD during childhood to be significantly associated with CRP (OR = 1.02, 95% CI [1.01, 1.04]). Individuals with two or more family deaths were 79 percent more likely to have elevated CRP than those with zero family deaths (OR = 1.79, 95% CI [1.07, 2.99]). Early adulthood PFD was not related to CRP. This study demonstrates a link between significant psychosocial stress in early life and immune-inflammatory functioning in late life, and suggests a mechanism explaining the link between early-life adversity and late-life health.     

Accentuated lines in the enamel of primary incisors from skeletal remains: A contribution to the explanation of early childhood mortality in a medieval population from Poland

Physiological disruptions resulting from an impoverished environment during the first years of life are of key importance for the health and biological status of individuals and populations. Studies of growth processes in archaeological populations point to the fact that the main causes of childhood mortality in the past are to be sought among extrinsic factors. Based on this assumption, one would expect random mortality of children, with the deceased individuals representing the entire subadult population. The purpose of this study is to explore whether differences in early childhood survival are reflected in differences in deciduous tooth enamel, which can provide an insight into the development of an individual during prenatal and perinatal ontogeny. Deciduous incisors were taken from 83 individuals aged 2.0–6.5 years from a medieval inhumation cemetery dated AD 1300–1600. Prenatal and postnatal enamel formation time, neonatal line width, and the number of accentuated lines were measured using an optical microscope. The significantly wider neonatal line and the higher frequency of accentuated lines in the enamel of the incisors of children who died at the age of 2–3 years suggest the occurrence of stronger or more frequent stress events in this group. These results indicate that in skeletal populations mortality was not exclusively determined by random external factors. Individuals predisposed by an unfavorable course of prenatal and perinatal growth were more likely to die in early childhood. Am J Phys Anthropol 157:402–410, 2015. © 2015 Wiley Periodicals, Inc.     

How do childhood ADHD symptoms affect labour market outcomes?

Inattention, hyperactivity and impulsivity are the main symptoms of ADHD, which affects up to one in ten European and North American children. Existing research shows these symptoms are associated with school exclusion and poor academic performance during childhood and adolescence. Using the British Cohort Study (n = 17,196 people born in April 1970), this is the first study of relationships between ADHD symptoms measured during childhood (age 10) and labour market outcomes measured beyond early adulthood (ages 26–46); and the first to explore the role of childhood circumstances (at birth) and academic performance (ages 10 and 26) in explaining those relationships. A one standard deviation increase in childhood symptoms reduced employment by up to two percentage points and pay by up to four percentage points. Differences in academic performance at age 10 accounted for almost half the observed variation in employment outcomes, indicating a possible role for educational interventions in schools.     

The impact of childhood malnutrition on schooling: evidence from Bangladesh

This paper examines the impact of childhood malnutrition on schooling performance in rural Bangladesh. The results reveal that malnourished children are less likely to enrol in school on time and achieve an age-appropriate grade by 26 percentage points and 31 percentage points, respectively. Other important determinants of schooling outcomes include infrastructure and education level of parents. One major contribution of this paper is the control for the endogeneity of malnutrition status, which otherwise might lead to bias estimates.     

Lockdown strictness and mental health effects among older populations in Europe

This paper investigates whether lockdown policies aggravated mental health problems of older populations (50 and over) in Europe during the first COVID-19 wave. Using data from the Survey of Health, Ageing and Retirement in Europe (SHARE COVID-19 questionnaire) and from the Oxford COVID-19 Government Response Tracker for 17 countries, we estimate the causal effect of lockdown policies on mental health by combining cross-country variability in the strictness of the policies with cross-individual variability in face-to-face contacts prior to the pandemic. We find that lockdown policies worsened insomnia, anxiety, and depression by 5, 7.2 and 5.1 percentage points, respectively. This effect was stronger for women and those aged between 50 and 65. Interestingly, lockdown policies notably damaged the mental health of healthy populations. We close with a discussion of lockdown policies targeted at individuals above 65 and/or with pre-existing conditions.     

Histological enamel indicator of childhood stress in prehistoric skeletal samples.

Although previous paleopathological studies have used disturbances in enamel formation as indicators of childhood stress, the full potential of this technique has not been realized. This paper presents a test case which demonstrates that the frequency of disturbed enamel formation (i.e., Wilson bands) is associated with other stress indicators (i.e., probability of dying and infectious lesions) in three prehistoric skeletal samples representing the Middle Woodland (10.3%), Mississippian Acculturated Late Woodland (21.4%), and the Middle Mississippian (40.0%). Additionally, the mean ages at death of individuals with at least one Wilson band are lower than those without bands.These results suggest that Wilson bands are an indicator of the relative proportion of individuals who are high susceptibles in prehistoric populations. The data also corroborate the hypothesis that the adoption of maize agriculture in the prehistoric American Midwest is associated with increased stress.     

The effects of breastfeeding and birth spacing on infant and early childhood mortality in Ethiopia

Research conducted in developing countries clearly demonstrates the positive effects of breastfeeding and widely spaced births on infant survival. The evidence is less clear as to whether these beneficial effects extend into early childhood, and under what conditions. In this paper we examine the effects of breastfeeding and birth spacing on neonatal, post-neonatal, and early childhood mortality in Ethiopia using data from the 1990 National Family and Fertility Survey. Our results provide clear evidence that the increased mortality risks associated with closely-spaced births continue beyond the first year of life into early childhood. Competition between siblings for food and maternal attention is the most probable explanation for this finding. We also find that breastfeeding beyond the second year of life is associated with higher mortality. Given that delayed weaning in Ethiopia is a common response to food shortages, we interpret this finding as further evidence of the negative consequences of resource deprivation for child survival.     

Migration and mental illness: What role do traditional childhood socialization practices play?

Interpretations of studies which show a correlation between migration and mental illness generally focus on sociocultural variables while giving scant attention to determinants of cognitive-personality orientations. This article examines childhood socialization practices as a key variable for comparing points of psychological stress between the traditional rural culture and the post-industrial urban culture. The hypothesis that harsh and restrictive childhood socialization practices foster the development of a cognitivepersonality orientation which increases the likelihood of maladaptive responses to culture change is illustrated by anthropological and psychological data obtained from Sicilians living in Sicily, the U.S.A. and Australia. Suggestions are given for minimizing the mental health risks involved during the critical transition period following migration.     

Lifetime fitness consequences of early‐life ecological hardship in a wild mammal population

Early‐life ecological conditions have major effects on survival and reproduction. Numerous studies in wild systems show fitness benefits of good quality early‐life ecological conditions (“silver‐spoon” effects). Recently, however, some studies have reported that poor‐quality early‐life ecological conditions are associated with later‐life fitness advantages and that the effect of early‐life conditions can be sex‐specific. Furthermore, few studies have investigated the effect of the variability of early‐life ecological conditions on later‐life fitness. Here, we test how the mean and variability of early‐life ecological conditions affect the longevity and reproduction of males and females using 14 years of data on wild banded mongooses (Mungos mungo). Males that experienced highly variable ecological conditions during development lived longer and had greater lifetime fitness, while those that experienced poor early‐life conditions lived longer but at a cost of reduced fertility. In females, there were no such effects. Our study suggests that exposure to more variable environments in early life can result in lifetime fitness benefits, whereas differences in the mean early‐life conditions experienced mediate a life‐history trade‐off between survival and reproduction. It also demonstrates how early‐life ecological conditions can produce different selection pressures on males and females.     

Effects of welfare reform on household food insecurity across generations

This study estimates the effects of welfare reform in the 1990s, which permanently restructured and contracted the cash assistance system in the U.S., on food insecurity—a fundamental form of material hardship—of the next generation of households. An implicit goal underlying welfare reform was the disruption of an assumed intergenerational transmission of disadvantage; however, little is known about the effects of welfare reform on the well-being of the next generation of adults. Using intergenerational data from the Panel Study of Income Dynamics and a variation on a difference-in-differences framework, this study exploits 3 sources of variation in childhood exposure to welfare reform: (1) risk of exposure across birth cohorts; (2) variation of exposure within cohorts because different states implemented welfare reform in different years; and (3) variation between individuals with the same exposure who were more likely and less likely to rely on welfare. We found that exposure to welfare reform led to decreases in food insecurity of the next generation of households, by about 10% for a 5-year increase in exposure, with stronger effects for individuals exposed for longer durations during childhood, individuals exposed in early childhood (0–5 years), and women. We also found smaller favorable effects for individuals whose mothers had less than a high school education, indicating that in terms of food insecurity, welfare reform led to relative disadvantages among the most disadvantaged and thus could be exacerbating socioeconomic and health inequalities.     

Differences in seasonal survival suggest species‐specific reactions to climate change in two sympatric bat species

Long‐lived animals with a low annual reproductive output need a long time to recover from population crashes and are, thus, likely to face high extinction risk, if the current global environmental change will increase mortality rates. To aid conservation of those species, knowledge on the variability of mortality rates is essential. Unfortunately, however, individual‐based multiyear data sets that are required for that have only rarely been collected for free‐ranging long‐lived mammals. Here, we used a five‐year data set comprising activity data of 1,445 RFID‐tagged individuals of two long‐lived temperate zone bat species, Natterer's bats (Myotis nattereri) and Daubenton's bats (Myotis daubentonii), at their joint hibernaculum. Both species are listed as being of high conservation interest by the European Habitats Directive. Applying mixed‐effects logistic regression, we explored seasonal survival differences in these two species which differ in foraging strategy and phenology. In both species, survival over the first winter of an individual's life was much lower than survival over subsequent winters. Focussing on adults only, seasonal survival patterns were largely consistent with higher winter and lower summer survival but varied in its level across years in both species. Our analyses, furthermore, highlight the importance of species‐specific time periods for survival. Daubenton's bats showed a much stronger difference in survival between the two seasons than Natterer's bats. In one exceptional winter, the population of Natterer's bats crashed, while the survival of Daubenton's bats declined only moderately. While our results confirm the general seasonal survival pattern typical for hibernating mammals with higher winter than summer survival, they also show that this pattern can be reversed under particular conditions. Overall, our study points toward a high importance of specific time periods for population dynamics and suggests species‐, population‐, and age class‐specific responses to global climate change.     

Early marriage and maternal health care utilisation: Evidence from sub-Saharan Africa

We use the recursive bivariate probit (RBVP) model to estimate the effects of early marriage on the utilisation of maternal health services in five sub-Saharan countries: Burkina Faso, Guinea, Mali, Niger and Chad. Based on recent Demographic and Health Surveys (DHS), we find that a woman who married before age 15 was 17 percentage points less likely to use prenatal services; and marrying before age 16 reduced that likelihood by 9.6 percentage points. We have not found any statistically significant reduction in maternal health care utilisation for women who married at age 17 or older.     

Understanding recent trends in childhood obesity in the United States

The prevalence of childhood obesity in the United States has more than tripled over the last four decades from 5 percent in 1978 to 18.5 percent in 2016. There is evidence for a break in trend in recent years: after growing from 0.4 to 0.7 percentage point per year between 1978 and 2004, the rate of increase has slowed to 0.1 percentage point per year from 2004 to 2016. To better understand these trends, in this paper we analyze a range of datasets that collect information on childhood obesity. We analyze the data overall, across the age distribution, across birth cohorts, and for subgroups of interest. We find steady increases in cohort-level obesity prevalence through approximately age 10, with levels unchanged thereafter, suggesting a need for additional interventions at early ages. We find that the prevalence of obesity has diverged by race and gender in recent years, especially among children entering kindergarten. Compared with 5-year-olds in 1997, 5-year-olds in 2010 were 2 percentage points more likely to be obese overall. Black and Hispanic 5-year-olds were 5 and 3 percentage points more likely to be obese, respectively, while whites had a 1 percentage point increase in obesity. However, overall and among all subgroups the rate of growth in obesity from kindergarten through 3rd grade has declined in recent years. Together, these findings can inform a future research literature that aims to target obesity interventions where they will be most impactful.     

Father absence predicts age at sexual maturity and reproductive timing in British men

Despite the widespread assumption that paternal investment is substantial in our species, previous studies have shown mixed results in relation to the impact of fathers on both offspring survival and reproductive outcomes. Using data from a large representative sample of British men, we tested whether father absence is associated with the timing of reproduction-related events among boys, while controlling for various cues denoting early childhood adversity. We further tested whether the loss of the father at different childhood stages matters, so as to assess whether early life is the most important period or if effects can be seen during later childhood. The results show that father absence before age seven is associated with early reproduction, while father absence between ages 11 and 16 only is associated with delayed voice-breaking (a proxy for puberty), even after adjusting for other factors denoting childhood adversity. We conclude that fathers do exert an influence on male reproductive outcomes, independently of other childhood adversities and that these effects are sensitive to the timing of father absence.