Pubertal development in Danish children: Comparison of recent European and US data
ABSTRACT Two recent epidemiological studies (PROS and NHANES III) from the USA noted earlier sexual maturation in girls, leading to increased attention internationally to the age at onset of puberty. We studied the timing of puberty in a large cohort of healthy Danish children in order to evaluate differences between USA and Denmark, as well as to look for possible secular trends in pubertal development. Healthy Caucasian children from public schools in Denmark participated in the study which was carried out in 1991-1993. A total number of 826 boys and 1,100 girls (aged 6.0-19.9 years) were included, and pubertal stages were assessed by clinical examination according to methods of Tanner. In boys testicular volume was determined using an orchidometer. We found that age at breast development 2 (B2) was 10.88 years, and mean menarcheal age was 13.42 years. Girls with body mass index (BMI) above the median had significantly earlier puberty (age at B2 10.42 years) compared with girls with BMI below the median (age at B2 11.24 years, p < 0.0001). Similarly, menarcheal age was significantly lower in girls with BMI above the median compared with girls with BMI below the median (13.12 vs. 13.70 years, p = 0.0012). In Danish boys we found that age at genital stage 2 (G2) was 11.83 years. Both sexes were significantly taller compared with data from 1964, but timing of pubertal maturation seemed unaltered. Finally, puberty occurred much later in Denmark compared with recent data from USA. We could not detect any downwards secular trend in the timing of puberty in Denmark between 1964 and 1991-1993 as seen in the US. Obesity certainly plays a role in the timing of puberty, but the marked differences between Denmark and USA cannot be attributed exclusively to differences in BMI. A possible role of other factors like genetic polymorphisms, nutrition, physical activity or endocrine disrupting chemicals must therefore also be considered. Therefore, we believe it is crucial to monitor the pubertal development closely in Denmark in the coming decades.
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- "In addition, we want to avoid tying the juvenile transition to a specific age: as we will explain in a later section, adrenarche is the hormonal switch initiating human juvenility, and its timing (just like that of puberty) is highly variable between individuals, usually in a range between 5 and 10. The modal transitional age in western countries is somewhere around 7 years, which corresponds to the conventional threshold usually employed to demarcate early from middle childhood; however, in addition to individual variation, it is reasonable to suppose (lacking specific research on this issue) that adrenarche timing should also show a degree of ethnic and regional variation similar to that observed in the timing of puberty (e.g., deMuinck Keizer-Schrama & Mul, 2001; Juul et al., 2006; Parent et al., 2003). For all these reasons, chronological age is an inadequate proxy as a marker of the juvenile transition. "
ABSTRACT: This paper presents a new perspective on the transition from early to middle childhood (i.e., human juvenility), investigated in an integrative evolutionary framework. Juvenility is a crucial life history stage, when social learning and interaction with peers become central developmental functions; here it is argued that the “juvenile transition” is a developmental switch point in the human life history, when both sex-related and individual differences in reproductive strategies are expressed after the assessment period provided by early childhood. Adrenarche, the secretion of adrenal androgens starting at the beginning of middle childhood, is proposed as the endocrine mechanism mediating the juvenile transition. It is argued that, in connection with the stress system, adrenal androgens enable adaptive plasticity in the development of reproductive strategies through integration of environmental and genetic factors. Finally, evidence is reviewed of both sex-related and individual differences arising during the juvenile transition, in the domains of attachment and aggression. Juvenility plays a central role in the ontogeny of behavior and personality; this paper contributes to defining its place within an integrated model of human development.Developmental Review 03/2009; 29(1):1 - 31. DOI:10.1016/j.dr.2008.09.001 · 3.23 Impact Factor
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- "One may ask if the morningness factor is more biological determined and the activity planning factor more cultural-social? Girls have delayed wake times (Laberge et al., 2001) which may be a result of an earlier onset of puberty (Juul et al., 2006). These results are more or less in accordance with Adan and Natale (2002), who compared the scores item by item and found differences in four items referring to the time of greatest efficiency, five items referring to sleep time and sleep phase, and only two referring to awakening time and sleep inertia. "
ABSTRACT: Individual differences in human biological rhythms and diurnal preference (morningness-eveningness) are often based on self-report scales. Here, we compare Spanish (N = 771) and German (N = 1,182) adolescents (12–18 years) using the Composite Scale of Morningness (CSM). A 3-factorial solution of the CSM was supported in both countries, morningness, activity planning, and alertness factors, and the last two factors were invariant across countries. Morningness decreased with age, and higher morningness was found in German pupils. Gender differences were not significant concerning the alertness factor but existed in the activity-planning factor with girls scoring higher, and in the morningness factor with boys scoring higher. Interactions suggest that the linear trend toward eveningness is less pronounced in Spanish adolescents, whereas German boys showed the steepest linear decline in their over time compared to German girls and to Spanish boys who showed a U-shaped tendency.European Psychologist 01/2008; 13(3):214-221. DOI:10.1027/1016-9040.13.3.214 · 1.31 Impact Factor
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- "Previous studies have reported a marked increase in SAD (Swedo et al., 1995) and depressive mood during the winter season (Rastad et al., 2006) in postpubertal girls versus boys. The onset of puberty varies, normally occurring between 8 and 13 years in girls and 9 and 14 years in boys (Juul et al., 2006). Onset coincides with the beginning of gonad functionality (menarche for females), while the end of puberty is defined as the moment when bone growth (epiphyseal closures) ceases (Bahadur and Hindmarsh, 2000). "
ABSTRACT: Most of the earlier studies on mood seasonality were conducted in adults and there are few available data on children and adolescents. In two cross sectional surveys, we examined the role of age and gender on seasonal sensitivity in subjects aged 10 to 25 years. In survey one, the Seasonal Pattern Assessment Questionnaire for Children and Adolescents (SPAQ-CA) was administered to 1709 subjects (845 females and 864 males) from 10 to 17 years. In survey two, the Seasonal Pattern Assessment Questionnaire (SPAQ) was administered to 1867 subjects (1061 females and 806 males) from 18 to 25 years. Only in survey one was a significant positive correlation found between age and Global Seasonality Score (GSS) (r=.29; p<.00001). Significant gender differences were found at age 14 years and above in survey one, and at all ages in survey two. The results support the hypothesis that seasonal sensitivity is higher in female subjects.Journal of Affective Disorders 01/2007; 97(1-3):155-60. DOI:10.1016/j.jad.2006.06.008 · 3.71 Impact Factor