Puberty and the Evolution of Developmental Science

Politics and the life sciences : the journal of the Association for Politics and the Life Sciences, 2001

The age of puberty in many populations has declined steeply over recent centuries and may be declining still. Consequently, today's children tend to experience the hormonal stresses of rapid development at younger ages than did their ancestors, around whose later, if not more gradual, maturation traditional behavioral expectations formed. Little has been made of this "rush to puberty" outside the life sciences. This article reviews its historical documentation, scholarly appreciation, epidemiological correlations, putative physiological and environmental explanations, sociological implications, and largely latent politics.

Journal of Adolescent Health, 2013

Purpose: Early puberty has been linked to higher rates of mental health problems in adolescence. However, previous studies commencing after the initiation of puberty have been unable to explore whether early puberty is preceded by higher rates of these problems. In a large national study, we aimed to determine whether difficulties in behavior and psychosocial adjustment are evident before as well as during the early pubertal transition. Methods: The Longitudinal Study of Australian Children recruited a nationally representative cohort of 4,983 children at age 4e5 years in 2004. This analysis includes 3,491 of these children (70.1%) followed up at ages 6e7, 8e9, and 10e11 years, with a completed parent report of stage of pubertal maturation at age 8e9 years. Parents reported behavior difficulties (Strengths and Difficulties Questionnaire) and psychosocial adjustment (Pediatric Quality of Life Inventory) at all four waves from ages 4e5 to 10e11 years. Results: Both boys and girls who entered puberty early (i.e., by age 8e9 years) also experienced poorer psychosocial adjustment at this age. These psychosocial differences were already evident at ages 4e5 and 6e7 years, and persisted to at least age 10e11 years. Similar patterns were evident for behavior difficulties, but only for boys; early puberty was not related to behavior difficulties in girls. Conclusions: Children with early puberty have different patterns of behavior and social adjustment from the preschool years through early adolescence. At least in part, the association between early-onset puberty and poor mental health appears to result from processes under way well before the onset of puberty.

Hormones and Behavior, 2013

Historical records reveal a secular trend toward earlier onset of puberty in both males and females, often attributed to improvements in nutrition and health status. The trend stabilized during the mid 20th century in many countries, but recent studies describe a recurrence of a decrease in age of pubertal onset. There appears to be an associated change in pubertal tempo in girls, such that girls who enter puberty earlier have a longer duration of puberty. Puberty is influenced by genetic factors but since these effects cannot change dramatically over the past century, environmental effects, including endocrine disrupting chemicals (EDCs), and perinatal conditions offer alternative etiologies. Observations that the secular trends in puberty in girls parallel the obesity epidemic provide another plausible explanation. Early puberty has implications for poor behavioral and psychosocial outcomes as well as health later in life. Irrespective of the underlying cause of the ongoing trend toward early puberty, experts in the field have debated whether these trends should lead clinicians to reconsider a lower age of normal puberty, or whether such a new definition will mask a pathologic etiology.

Developmental Psychobiology, 2010

This article examines selected findings regarding the consequences of difference in timing of pubertal onset in order to build an explanatory model of puberty in context. We also seek to shed light on possible prevention efforts targeting adolescent risk. To date, there is substantial evidence supporting early onset effects on both internalizing and externalizing problems during the adolescent decade and possibly beyond. However, such effects do not directly speak to preventive intervention. The biological, familial, and broader relationship contexts of puberty are considered along with unique contexts for early maturing girls versus boys. Finally, we identify potential strategies for intervention based on these explanatory models. ß 2010 Wiley Periodicals, Inc. Dev Psychobiol 52: 254-262, 2010.

2013

Despite substantial heritability in pubertal development, much variation remains to be explained, leaving room for the influence of environmental factors to adjust its phenotypic trajectory in the service of fitness goals. Utilizing evolutionary development biology (evo-devo), we examine adolescence as an evolutionary life-history stage in its developmental context. We show that the transition from the preceding stage of juvenility entails adaptive plasticity in response to energy resources, other environmental cues, social needs of adolescence and maturation toward youth and adulthood. Using the evolutionary theory of socialization, we show that familial psychosocial stress fosters a fast life history and reproductive strategy rather than early maturation being just a risk factor for aggression and delinquency. Here we explore implications of an evolutionarydevelopmental-endocrinological-anthropological framework for theory building, while illuminating new directions for research.

Spotlight on Exploratory Research in Health, 2020

Introduction: This paper uses the case of puberty to characterize a new health science framework called Bio3Science and to provide an example of how trending research on biosocial mechanisms can be put to use to bridge siloed disciplines as well as the translational gap. Examined as an intricate, open-ended problem of scientific understanding, puberty offers a window to examine how three dimensions of human life – biology, biography, and biosphere – can be understood to shape human health and disease. Methods: Using the Bio3Science framework, a biosocial model of puberty was developed and critiqued by an interdisciplinary group of health science and social science researchers in a design studio setting. Results: The design and critique process resulted in a model and new conceptual framework that depicts puberty as a highly variable life experience that integrates multiple dense interactions and context-specific responses; within this model, the gene regulatory network (GRN) transformed from a biological to a biosocial mechanism, with conceptual and concrete applications. Conclusions: By providing a new, generalizable framework for understanding the integration of biology, biography, and biosphere in health research, opportunities emerge for more interdisciplinary work puberty, but also and more broadly, for more collaborative, inter-epistemological health research through the Bio3Science framework.

Journal of Youth and Adolescence

There is inconsistency in the outcome measures of biological and psychosocial studies using measures of puberty as a predictor. For example, some studies show that maturational timing may have differential influences (positive, negative, or no effect) depending on the specific disorder, dimension of measure, and gender. Other studies have suggested that some effects may be more directly linked to pubertal stage or hormone concentrations rather than timing per se. This study outlines several conceptual and methodological issues that may be relevant to addressing these inconsistencies, in the context of examining data from a study of maturational hormones obtained from a unique longitudinal cohort of 24 girls (age 10.0 ± 1.6 years) and 36 boys (age 10.4 ± 1.6 years) in the early part of puberty, where the developmental trajectory of these hormones were tracked annually in 65% of the sample. We explored the contributions of measures of pubertal growth and sociodemographic factors on hormone concentrations. In brief, it appears that no single measure best captures the maturational processes during puberty and suggests that multiple processes are occurring in parallel. Several conceptual and methodological implications are discussed that may guide investigators in interpreting existing studies of pubertal timing and behavior as well as in conducting future studies.

Journal of Youth and Adolescence, 1985

Journal of Adolescent Health, 2008

Puberty or pubertal timing can be a key variable in research, be it as a predictor or an outcome. Puberty is important in clinical practice as well. Although empirical studies with adolescents often do not include this variable, the literature has provided us with evidence of its importance for both research and practice. In this issue of the Journal, we are presented with an article that reports age at menarche has decreased across the last several generations . So, you ask, "What is new that we haven't already heard? What does the article have to offer?" Read on as we provide you with some interpretations and questions, as well as some food for thought about the next generation of studies. In brief, the study by Harris and colleagues also found a decrease in age at menarche, but the study design is different from many national databases that primarily used pubertal age or young adult participants. In their study, the authors drew from a national sample of over 8000 Canadian females age 15 and older. In a cross-sectional analysis of women whose date of birth ranged from before 1933 to those born as late as 1990, a secular trend in age at menarche was noted; specifically, age at menarche decreased by 8.8 months across the 5 or so decades observed in the study. This study provides complimentary findings similar to other studies showing this decline in age at menarche . The authors address the limitation of using a cross-sectional study, and briefly mention that a margin of error may be evident in reporting age at menarche both proximal and distal to the event. There is some concern that the authors have minimized the significance of this selfreport "error." That is, when the age span is so vast (e.g., women age 15 to >70 years) do we really know how much error there is in reporting? Further, there is at least one primary concern that was not raised by the authors. If one examines Figure , showing the relationship of age cohort to age at menarche, it appears that the relationship may be nonlinear . However, a linear model was used in the analysis. There is a curious "spike" in age at menarche in the 1964 to 1968 age cohort showing that age at menarche jumped to 13.4 years; up from about 12.8 years in the previous cohort. Similarly, in the 1969 to 1973 cohort that follows, age at menarche falls to 12.5 years, which is nearly a year earlier than the 1964 to 1968 cohort. Other rises and falls are noted across age cohorts, but none of this magnitude. It would be useful to determine if a nonlinear statistical model would provide a better fit to the data or if pair-wise comparisons noting significant differences would be appropriate in certain cases. Potentially, the outcome or interpretation of this study could change. Other issues of import include that outliers were not addressed in the article. Age at menarche ranged from 7 to 26 years, clearly illustrating that, at the minimum, some clinical abnormalities may exist in participants toward each of those extremes. Additionally, although race/ethnicity was controlled for in the analyses, it would have been helpful to know what the racial breakdown was because there is a literature on differences in timing of puberty by race . Would there be richer information if analyses were conducted separately? Harris and colleagues do go beyond just reporting that age at menarche is earlier. Their second aim focused on timing of menarche and its association with adult body mass index (BMI); that is, BMI at time of data collection, when females ranged in age from 15 to over 70 years of age.

Journal of Youth and Adolescence, 1984

Problems in studying and defining pubertal events during early adolescence are examined in this paper. Whether puberty is best characterized as a social construction or as a physical event and whether early adolescence is best considered a transitional or distinct life period are discussed. Then, the markers or life events associated with puberty and possible boundaries of early adolescence are considered. Finally, possible models for studying pubertal change are discussed, focusing on timing of events, mediated effects, biobehavioral interaction, and cumulative risk models.