RESUMEN

Introduction: Maternal capital (MC) is a broad term from evolutionary biology, referring to any aspects of maternal phenotype that represent resources available for investment in offspring. We investigated MC in breastfeeding mothers of late preterm and early term infants, examining its relationship with infant and breastfeeding outcomes. We also determined whether MC modified the effect of the relaxation intervention on these outcomes. Methods: The data was collected as part of a randomized controlled trial investigating breastfeeding relaxation in 72 mothers of late preterm and early term infants. Indicators of MC (socioeconomic, social, somatic, reproductive, psychological, and cognitive) were collected at baseline at 2-3 weeks post-delivery. Principal Component Analysis was conducted for the MC measures and two components were identified: 1."Subjective" maternal capital which included stress and depression scores, and 2."Objective" maternal capital which included height, infant birth weight, and verbal memory. Univariate linear regression was conducted to assess the relationship between objective and subjective MC (predictors) and infant growth, infant behavior, maternal behavior, and infant feeding variables (outcomes) at 6-8 weeks. The interaction of MC and intervention assignment with outcomes was assessed. Results: Higher objective MC was significantly associated with higher infant weight (0.43; 95%CI 0.21,0.66) and length z-scores (0.47; 95%CI 0.19,0.76), shorter duration of crying (-17.5; 95%CI -33.2,-1.9), and lower food (-0.28; 95%CI -0.48,-0.08) and satiety responsiveness (-0.17; 95%CI -0.31,-0.02) at 6-8 weeks. It was also associated with greater maternal responsiveness to infant cues (-0.05, 95%CI -0.09,-0.02 for non-responsiveness). Greater subjective maternal capital was significantly associated with higher breastfeeding frequency (2.3; 95%CI 0.8,3.8) and infant appetite (0.30; 95%CI 0.07,0.54). There was a significant interaction between the intervention assignment and objective MC for infant length, with trends for infant weight and crying, which indicated that the intervention had greater effects among mothers with lower capital. Conclusion: Higher MC was associated with better infant growth and shorter crying duration. This was possibly mediated through more frequent breastfeeding and prompt responsiveness to infant cues, reflecting greater maternal investment. The findings also suggest that a relaxation intervention was most effective among those with low MC, suggesting some reduction in social inequalities in health.

RESUMEN

Background and objectives: Women's nutritional status is important for their health and reproductive fitness. In a population where early marriage is common, we investigated how women's nutritional status is associated with their age at marriage (marking a geographical transfer between households), and at first pregnancy. Methodology: We used data from a cluster-randomized control trial from lowland Nepal (n = 4071). Outcomes including body mass index (BMI) were measured in early pregnancy and trial endpoint, after delivery. We fitted mixed-effects linear and logistic regression models to estimate associations of age at marriage and age at pregnancy with outcomes, and with odds of chronic energy deficiency (CED, BMI <18.5 kg/m2), at both timepoints. Results: BMI in early pregnancy averaged 20.9 kg/m2, with CED prevalence of 12.5%. In 750 women measured twice, BMI declined 1.2 (95% confidence interval 1.1, 1.3) kg/m2 between early pregnancy and endpoint, when CED prevalence was 35.5%. Early pregnancy was associated in dose-response manner with poorer nutritional status. Early marriage was independently associated with poorer nutritional status among those pregnant ≤15 years, but with better nutritional status among those pregnant ≥19 years. Conclusions and implications: The primary determinant of nutritional status was age at pregnancy, but this association also varied by marriage age. Our results suggest that natal households may marry their daughters earlier if food insecure, but that their nutritional status can improve in the marital household if pregnancy is delayed. Marriage age therefore determines which household funds adolescent weight gain, with implications for Darwinian fitness of the members of both households.

RESUMEN

Adverse ecological and social conditions during early life are known to influence development, with rippling effects that may explain variation in adult health and fitness. The adaptive function of such developmental plasticity, however, remains relatively untested in long-lived animals, resulting in much debate over which evolutionary models are most applicable. Furthermore, despite the promise of clinical interventions that might alleviate the health consequences of early-life adversity, research on the proximate mechanisms governing phenotypic responses to adversity have been largely limited to studies on glucocorticoids. Here, we synthesize the current state of research on developmental plasticity, discussing both ultimate and proximate mechanisms. First, we evaluate the utility of adaptive models proposed to explain developmental responses to early-life adversity, particularly for long-lived mammals such as humans. In doing so, we highlight how parent-offspring conflict complicates our understanding of whether mothers or offspring benefit from these responses. Second, we discuss the role of glucocorticoids and a second physiological system-the gut microbiome-that has emerged as an additional, clinically relevant mechanism by which early-life adversity can influence development. Finally, we suggest ways in which nonhuman primates can serve as models to study the effects of early-life adversity, both from evolutionary and clinical perspectives.

Asunto(s)

Adaptación Biológica , Evolución Biológica , Crecimiento y Desarrollo , Modelos Biológicos , Animales , Antropología Física , Aves , Femenino , Glucocorticoides , Humanos , Masculino , Mamíferos , Salud Materna , Microbiota , Estrés Fisiológico

RESUMEN

BACKGROUND: Fetal and neonatal malnutrition impacts the timing of the onset of puberty. The timing of puberty onset has been shown to be a rough indicator of noncommunicable disease (NCD) risk. Recent advances in understanding the various inter-related neurochemical and genetic controls underpinning puberty onset have shed new light on these interesting and important phenomena. These studies have suggested that developmental trajectory is set very early by epigenetic mechanisms that serve to adjust phenotype to environment. OBJECTIVE: The aims of this article are to review the most recent research into the proximate mechanisms that initiate puberty; to explore how the activation of those mechanisms could be affected by nutritional cues received during fetal and neonatal life; and, finally, to briefly explore the ramifications for public health. METHODS: An extensive literature review was performed using PubMed (1950 to September 2010) and Google Scholar (1980 to September 2010) using the search terms "puberty onset", "perinatal", and "neonatal malnutrition". English language, original research, and review articles were examined; pertinent citations from these articles were also assessed. RESULTS: Literature detailing biochemical pathways and evolutionary explanations of human puberty itself led quickly to a noteworthy connection between neonatal malnutrition, puberty onset, and NCD risk. A strong connection was found between maternal malnutrition during critical windows (followed by catch-up growth in childhood) and an accelerated onset of puberty. Children subject to early nutritional insult not only are likely to undergo puberty earlier but also show an increase in their risk of developing NCDs in later life. Several authors have suggested that this relationship may show potential as an early proxy indicator of susceptibility to these types of diseases, which are an increasing concern in both affluent and developing countries. CONCLUSIONS: More attention should be paid to fetal and neonatal nutrition and puberty onset if we are to meaningfully curb the troubling growth of NCDs now and in the future. Efforts to improve maternal conditions among vulnerable poor groups as well as more affluent groups worldwide should be explored, especially among groups undergoing rapid nutritional transition.