Parent-offspring conflict and the cultural ecology of breast-feeding

Women’s lifetime reproductive profiles and frailty among aging individuals in the USA and the Philippines

Frailty, particularly traits which are related to sex steroid hormone production, results from the age-associated decline in function considered to be part of the typical aging process. This process may vary with influences including environmental, biological, or lifestyle factors. An area of concern that has received relatively little attention is the impact of cumulative lifetime changes in sex steroid hormones related to the traits we see that typify the human aging process. Women’s lifetime reproductive profiles include menstrual/ovulatory cycles, gestation, and lactation, all of which respond to changes in sex steroid hormone levels. Here, we review data on reproductive profiles and risks of frailty among post-menopausal women. In the current study, our team collected reproductive histories of women to determine the estimated number of lifetime reproductive cycles (ELC). We interviewed 44 women in the USA and 67 women in the Philippines aged 65 years plus to obtain data on reproductive cycles, pregnancy, and breastfeeding. Participants completed several frailty tasks including grip strength, a sit-to-stand test, and gait speed. While ELC was not associated with frailty in the US population, higher ELC was associated with lower frailty among the Philippine population. The current study should be considered as an exploratory project investigating field-friendly methods to use when considering lifetime reproductive histories and the influence on the aging process.

Population-Based Survey Showing That Breastfed Babies Have a Lower Frequency of Risk Factors for Sudden Infant Death Syndrome Than Nonbreastfed Babies

Justification: Breastfeeding provides the best infant food, and closeness to the mother is crucial for successful breastfeeding. However, sharing parents' beds and sleeping on the stomach poses a high risk for sudden infant death syndrome (SIDS). There is little information on these practices regarding the Spanish population. Objective: To explore breastfeeding and bed-sharing practices in the study population Materials and Methods: A cross sectional observational study was conducted through an anonymous telephone survey with a representative random sample of babies born in the Health Area of La Marina Baixa, Alicante, between 2018 and 2019. A previous-day strategy was implemented to determine the feeding and bed-sharing variables. Results: The total breastfeeding and formula-feeding rates were 47.0% and 52.9%, respectively. The overall bed-sharing rate was 66.5%. The breastfeeding rate was 86.4% with bed-sharing and 13.6% without bed-sharing. The rate of prone sleeping position in children younger than 6 months of age was 9.3-3.5% with breastfeeding and 5.8% with formula feeding. Lower frequencies of tobacco, alcohol, and nonsupine sleeping positions were observed among mothers who practiced breastfeeding and bed-sharing. Conclusions: We found a close relationship between breastfeeding and bed-sharing and a lower frequency of SIDS risk factors associated with both practices. Families should be informed about the risk factors associated with SIDS to encourage safe bed-sharing while avoiding recommendations that discourage breastfeeding.

Insights on patterns of developmental disturbances from the analysis of linear enamel hypoplasia in a Neolithic sample from Liguria (northwestern Italy)

OBJECTIVE

To assess developmental disturbances through the analysis of linear enamel hypoplasia (LEH) frequency and to infer environmental stress and life history within Neolithic communities from Liguria (Italy).

MATERIALS

43 unworn/minimally worn permanent anterior teeth of 13 individuals recovered from nearby caves and dated to c. 4800-4400 cal. BCE.

METHODS

LEH defects were identified with high-resolution macrophotos of dental replicas, age at LEH was calculated via perikymata counts. LEH defects matched between two or more teeth were considered as systemic disturbances. LEH frequency by age classes was analyzed via GLZ and Friedman ANOVA.

RESULTS

Number of matched defects per individual range between 2-12. The mean LEH per individual was highest in the 2.5-2.99 age category, with a significant increase relative to earlier growth stages, followed by a decline.

CONCLUSION

LEH may reflect life-history in the local ecology of Neolithic Liguria, where several individuals with osteoarticular tuberculosis have been recorded. Disease burden may have triggered developmental disturbances around the time of weaning. Age at first defect was negatively correlated with age at death and positively with the total number of defects, suggesting that early stress may have affected survivorship.

SIGNIFICANCE

The study contributes to the reconstruction of ecological pressures among Neolithic people of Liguria, and informs on environmental challenges during the Neolithic adaptive expansion.

LIMITATIONS

The visual examination of macrophotos is prone to observer error; mid-crown tends to display more visible LEH due to tooth architecture.

SUGGESTIONS FOR FURTHER RESEARCH

Apply different quantitative methods to examine severity and duration of disturbances.

Multi-proxy stable isotope analyses of dentine microsections reveal diachronic changes in life history adaptations, mobility, and tuberculosis-induced wasting in prehistoric Liguria (Finale Ligure, Italy, northwestern Mediterranean)

OBJECTIVE

To reconstruct breastfeeding and weaning practices, metabolic stress including tuberculosis-induced wasting, and residential mobility of children in Neolithic and Metal Ages to infer their local ecologies.

MATERIALS

Seven permanent teeth from individuals dated to the Neolithic, Copper, Bronze, and Iron Ages buried in nearby caves in western Liguria, Italy.

METHODS

Carbon, nitrogen, and sulfur stable isotope analyses on dentine microsections. Tooth maturation was used to calculate age at death.

RESULTS

Two Neolithic children present longer pattern of weaning and appear to have been weaned using animal protein in contrast to the earlier weaning of Metal Ages children, which were probably weaned with vegetable resources. Sulfur isotopes suggest local origin of Neolithic and Cooper Age children, and non-local origins for Bronze and Iron Age children. Intense catabolism in the last two years is apparent in the adolescent with tuberculosis.

CONCLUSIONS

Shortening in weaning patterns during the Metal Ages are likely driven by the intensification of agricultural practices and cultivation of new crops during Bronze and Iron Ages. Neolithic food choices and delayed weaning patterns may represent one of the strategies to maximize growth and immune potential in a local economy/ecology with high-infectious load. Tuberculosis was a chronic and long-lasting disease.

SIGNIFICANCE

The first combined carbon, nitrogen, and sulfur analysis on prehistoric dentine microsections revealing changing human life history adaptations within the same region.

LIMITATIONS

Small sample size.

SUGGESTIONS FOR FURTHER RESEARCH

Increase the sulfur isotope dataset, use new EA-IRMS equipment, and provide data on amino acid to better define weaning food composition.

Exploring parental perceptions and knowledge regarding breastfeeding practices in Rajanpur, Punjab Province, Pakistan

BACKGROUND

Exclusive breastfeeding is significantly associated with strong infant immunity and optimal development. The importance of breastfeeding is underestimated. Parental lack of knowledge and unhealthy practices regarding breastfeeding deprive infants of their basic right to mother's milk. In developing countries, including Pakistan, with high child mortality and malnutrition, healthy breastfeeding practices can bring positive changes in child health status. From this perspective, the present study aims to understand parents' knowledge, attitudes and practical encounters with breastfeeding practices and the factors that prevent them from adopting such practices.

METHODS

A qualitative study was carried out in both rural and urban settings in Rajanpur District of Punjab Province, Pakistan. We conducted 12 focus-group discussions (FGDs) that involved 38 mothers and 40 fathers with children aged under two years who were being breastfed. A thematic content analysis of data collected through FGDs was performed manually. The themes were both inductive and deductive in nature.

RESULTS

The study found that a majority of participants believed that the first thing given to an infant after birth should not be breast milk but honey, rose flower, or goat's milk from the hands of an elder in the family or a religious person. No cleanliness measures were practised in this regard. The participants had misconceptions about the benefits of colostrum, which frequently prevented it being given to newborns. Participants reported many factors, such as: insufficient milk syndrome (slow growth of infants due to insufficient daily breast milk intake), a mother's high workload, lack of social support, the influence of culturally designated advisors, and the promotion and marketing strategies of infant formula companies, that undermined exclusive breastfeeding efforts and encouraged mothers to switch to infant formula.

CONCLUSIONS

Culturally acceptable and integrated public health interventions are needed to improve the breastfeeding-related health literacy and practices of parents, grandparents and communities. This will ultimately reduce the high infant mortality and malnutrition rates in Pakistan.

The biological evolution of conscience – from parent-offspring conflict to morality

In this paper, two theories regarding the biological evolution of morality with conscience as its central regulatory agency are compared and contrasted. One theory (“navigator theory”) interprets conscience as a strategically operating agency for the optimum balance between selfish and altruistic behavioral tendencies to maximize gains in cooperation in view of social complexity. From this standpoint, conscience serves the evolved self-interest of the person having a conscience. In contrast hereto, the second theory (“helper theory”) locates the evolutionary origins of conscience on the battlefield of the parent-offspring conflict through intrafamilial demands for altruism. Functions of conscience, and thus human morality in a narrower sense, evolved during the transition of hominines to cooperative breeding and the novel helper conflict emerging through this evolution. The “helper theory” of the evolution of conscience can resolve some of the theoretical and empirical inconsistencies of the conventional “navigator theory”, in particular, the contradiction between the consequentialistic regulation of altruistic behavior and the non-consequentialistic nature of the judgment of conscience. And in contrast to the “navigator theory”, it is compatible with the observation that behavior guided by a conscience is not infrequently disastrous for one’s own fitness outcome.

Milk immunity and reproductive status among Ariaal women of northern Kenya

Abstract Background: The immune factors in human milk protect infants from infection and promote immune development. Evidence suggests that the production of milk-specific immunoproteins is energetically costly, making them a form of maternal investment in offspring health that is subject to life history trade-offs.

AIM

This research tests the relationship between measures of reproductive effort and the production of milk immunoglobulin A (IgA) among Ariaal women, a settled northern Kenyan pastoralist population that experiences nutritional and disease stress.

SUBJECTS AND METHODS

Two hundred and forty-three lactating Ariaal women participated in a questionnaire, anthropometric measurement and milk collection. Milk IgA was analysed using ELISA.

RESULTS

There was a significant U-shaped relationship between post-partum months and milk IgA, reflecting decreasing investment in the current offspring over the early post-partum period and subsequent recovery of maternal energy status near the end. There was also a significant inverse U-shaped relationship between milk IgA and parity, with high parity women showing a drop in milk IgA. In contrast, anthropometric measures of energy status were not associated with the production of milk IgA.

CONCLUSION

This research shows that patterns of reproductive investment can be demonstrated in milk IgA in the absence of measured energy changes.

The evolutionary ecology of early weaning in Kilimanjaro, Tanzania

Public health recommendations promote prolonged breastfeeding of all children; however, parental investment (PI) theory predicts that breastfeeding will be allocated among a mothers' offspring to maximize her reproductive success. We evaluated PI in terms of risk for weaning before age two among 283 children in Kilimanjaro, Tanzania. Results demonstrate: (i) a Trivers-Willard effect--high socioeconomic status (SES) females and low SES males were more likely to be weaned early; (ii) later-born children were less likely to be weaned early; (iii) higher birthweight children were less likely to be weaned early, and (iv) no effect of cattle (a source of supplementary milk) ownership. These associations were largely independent and remained significant in models controlling for potential confounders; however, the inverse association between early weaning and birth order lost significance in the model containing birthweight. These patterns were observed despite public health recommendations encouraging breastfeeding for at least two years.

Nighttime parenting strategies and sleep-related risks to infants

A large social science and public health literature addresses infant sleep safety, with implications for infant mortality in the context of accidental deaths and Sudden Infant Death Syndrome (SIDS). As part of risk reduction campaigns in the USA, parents are encouraged to place infants supine and to alter infant bedding and elements of the sleep environment, and are discouraged from allowing infants to sleep unsupervised, from bed-sharing either at all or under specific circumstances, or from sofa-sharing. These recommendations are based on findings from large-scale epidemiological studies that generate odds ratios or relative risk statistics for various practices; however, detailed behavioural data on nighttime parenting and infant sleep environments are limited. To address this issue, this paper presents and discusses the implications of four case studies based on overnight observations conducted with first-time mothers and their four-month old infants. These case studies were collected at the Mother-Baby Behavioral Sleep Lab at the University of Notre Dame USA between September 2002 and June 2004. Each case study provides a detailed description based on video analysis of sleep-related risks observed while mother-infant dyads spent the night in a sleep lab. The case studies provide examples of mothers engaged in the strategic management of nighttime parenting for whom sleep-related risks to infants arose as a result of these strategies. Although risk reduction guidelines focus on eliminating potentially risky infant sleep practices as if the probability of death from each were equal, the majority of instances in which these occur are unlikely to result in infant mortality. Therefore, we hypothesise that mothers assess potential costs and benefits within margins of risk which are not acknowledged by risk-reduction campaigns. Exploring why mothers might choose to manage sleep and nighttime parenting in ways that appear to increase potential risks to infants may help illuminate how risks occur for individual infants.

Japan-France-US comparison of infant weaning from mother's viewpoint

Background: Breastfeeding and weaning are strongly connected with infant-mother mutual autonomy, and hence are good touchstones to examine the characteristics of the mother-child relationship. Comparison of the weaning practice gives a framework to understand characteristics of the mother-infant relationship. Objective: The purpose of this study was to compare three industrialised countries concerning the relationship between feeding and weaning practices and its reasons, mother's perception of child care, and of breast milk and formula. Methods: A questionnaire study on weaning practice was conducted for 310 Japanese, 756 French, and 222 American mothers with 4- to 20-month-old infants. Results: French mothers expected and had accomplished weaning at an earlier age of the infant, compared to Japanese and American mothers. Perceived insufficiency of breast milk was the leading reason for the termination of breastfeeding for Japanese mothers at the earlier stages, whereas back to work was the more important reason for French mothers. Japanese mothers were more negative in their image of themselves as mothers, whereas French mothers felt more burdened by child-care. Japanese mothers who terminated breastfeeding because of perceived breast milk insufficiency were also those who were less motivated to breastfeed. Conclusion: Weaning is a significant framework to interpret cultural differences in mother-infant relationship. The perceived insufficiency is interpreted as a solution of conflict between the social pressure to breastfeed and its burden.

Kowakare: a new perspective on the development of early mother-offspring relationship

The mother–offspring relationship has components of both positivity and negativity. Kowakare is a new concept introduced to explain an adaptive function of the negativity in the early mother-offspring relationship. Kowakare is the psycho-somatic development of the relationship as the process of accumulation in the otherness of offspring. Early human Kowakare has two frameworks, biological inter-body antagonism and socio-cultural allomothering compensating the antagonism. Some features of feeding/weaning, parental aversion to offspring’s bodily products, and transition from dyad to triad relationship (proto–triad relationship) in tactile play are discussed. Early human Kowakare is promoted by allomothering with the nested systems of objects/persons/institutions as interfaces between mother and offspring. Kowakare makes mother–offspring relationship a mutually autonomous and cooperative companionship.

Life history theory and the immune system: steps toward a human ecological immunology

Within anthropology and human biology, there is growing interest in immune function and its importance to the ecology of human health and development. Biomedical research currently dominates our understanding of immunology, and this paper seeks to highlight the potential contribution of a population-based, ecological approach to the study of human immune function. Concepts from life-history theory are applied to highlight the major challenges and demands that are likely to shape immune function in a range of ecological contexts. Immune function is a major component of maintenance effort, and since resources are limited, trade-offs are expected between investment in maintenance and other critical life-history functions involving growth and reproduction. An adaptationist, life-history perspective helps make sense of the unusual developmental trajectory of immune tissues, and emphasizes that this complex system is designed to incorporate information from the surrounding ecology to guide its development. As a result, there is substantial population variation in immune development and function that is not considered by current biomedical approaches. In an attempt to construct a framework for understanding this variation, immune development is considered in relation to the competing life-history demands that define gestation, infancy, childhood, adolescence, and adulthood. Each life stage poses a unique set of adaptive challenges, and a series of hypotheses is proposed regarding their implications for immune development and function. Research in human ecological immunology is in its earliest stages, but this is a promising area of exploration, and one in which anthropology is well-positioned to make important contributions.

Availability of childcare support and nutritional status of children of non-working and working mothers in urban Nepal

In many developing countries, poor women have multiple roles, and often their time constraints are so severe that their participation in income-generating activities results in reduced childcare time, which in turn affects child health. Previous studies have tended to investigate how childcare support influences nutrition of children with working mothers' based on comparisons with non-working mothers. However, non-working mothers are not a homogeneous group, and we therefore need to distinguish between those who need not work and those who wish to but cannot, for example, due to a lack of substitute caregivers. We examined the association between availability of childcare support and the nutritional status of children of both non-working and working mothers in poor areas of Pokhara, a sub-metropolitan city in Nepal. We recruited 150 children of age 10-24 months from the waiting lists of 17 daycare centers and measured their weights and heights. Those with height-for-age and weight-for-age Z scores of less than -2 were defined as stunted and underweight, respectively. To collect information on childcare practices and socioeconomic characteristics, mothers were interviewed using a pre-tested structured questionnaire. Unavailability of adult childcare support was associated with increased risk of malnutrition among children of both non-working and working mothers. Peer childcare was not significantly associated with child malnutrition among children of non-working mothers, but it was associated with an increased risk of malnutrition among children of working mothers. Although further longitudinal research is required, we suggest that childcare support from adult substitute caregivers is essential for children of non-working mothers with limited resources.

Infant feeding practices and chronic child malnutrition in the Indian states of Karnataka and Uttar Pradesh

As measured by degree of stunting, close to half of India's children suffer from chronic malnutrition and about a quarter from severe chronic malnutrition. Data from the 1998-1999 National Family Health Survey (NFHS) are analysed to assess whether recommended infant feeding practices help to alleviate the prevalence of stunting. The evidence supports some recommended practices, including the advice that mother not squeeze the colostrum from her breasts, not use a feeding bottle with a nipple, exclusive breastfeeding for the first 4-6 months and feeding supplementary foods (solids and mushy foods) at about 7 months, and suggests that, for some children, better feeding practices could reduce the prevalence of severe stunting by up to 30%. The paper also examines a range of other issues related to stunting--whether medical supplementations and inoculations have an effect, whether mothers more actively involved in health decisions have less stunted children, and the links between stunting, diarrhoea and anaemia. An explanation is offered for the positive relationship between using oral rehydration salts and stunting.

Evolutionary approach to below replacement fertility

The large human brain, the long period of juvenile dependence, long life span, and male support of reproduction are the co-evolutionary result of the human niche based on skill-intensive techniques of resource accrual. The regulation of fertility under traditional conditions is based upon a co-evolved psychology and physiology where adjustments of investment in offspring depend upon the returns to skill and mortality hazards. When all wealth is somatic, the hormonal system controlling ovulation and implantation translates income into genetic descendants. In modern society the existence of extra-somatic wealth is a critical condition to which our evolved proximate physiological mechanisms do not respond. However, psychological mechanisms regulating parental investment in offspring quality may lead to greater and greater investment in own and offspring education, a smaller desired family size, a delay in the onset of reproduction, and a reduction in the total numbers of offspring produced. This delay in reproduction can cause many individuals to produce fewer children than desired because fecundity falls during the reproductive part of the life course. As more individuals in a society follow this pattern, more will fail to reach their desired family size. At the same time the effective use of birth control decreases the numbers of families producing more children than desired. Below replacement fertility can result. Predictions from this model were tested using data from the National Survey of Families and Households and the Albuquerque Men study.