Splitting hairs

Precocious puberty

Precocious puberty (PP) is a common reason for referral to pediatric endocrinology clinics, with a strong female predominance. PP is a broad term encompassing benign variants of normal development, gonadotropin-dependent precious puberty (GDPP), and gonadotropin-independent precocious puberty (GIPP). This article reviews the definitions, physiology, clinical presentation, evaluation and treatment of these conditions.

Incidence and Prevalence of Central Precocious Puberty in Korea: An Epidemiologic Study Based on a National Database

OBJECTIVES

To investigate the prevalence and incidence of central precocious puberty in Korea using claims data provided by the Health Insurance Review and Assessment Service in Korea as the population-based epidemiologic study.

STUDY DESIGN

In this national registry-based, longitudinal, epidemiologic study, patients who were registered with an International Classifications of Diseases, Tenth Revision diagnosis of central precocious puberty (E22.8 according to International Classifications of Diseases, Tenth Revision) and treated with gonadotropin-releasing hormone agonist were included. We assessed the age- and sex-specific prevalence and incidence rates of central precocious puberty in Korea from 2008 to 2014.

RESULTS

A total of 37 890 girls and 1220 boys were newly registered with a diagnosis of central precocious puberty from 2008 to 2014. The overall incidence of central precocious puberty during the study period was 122.8 per 100 000 persons (girls, 262.8; boys, 7.0). The overall prevalence of central precocious puberty during the study period was 193.2 per 100 000 persons (girls, 410.6; boys, 10.9). The incidence and prevalence of central precocious puberty steeply increased during the study period in both girls and boys.

CONCLUSIONS

This epidemiologic study, based on a national registry that included Korean children, demonstrated that the incidence and prevalence rates of central precocious puberty were high and increased steeply during the study period. Further investigations to determine the underlying causes for this rapid increase in central precocious puberty are needed.

Early puberty in 11-year-old girls: Millennium Cohort Study findings

OBJECTIVE

Early puberty in girls is linked to some adverse outcomes in adolescence and mid-life. We address two research questions: (1) Are socioeconomic circumstances and ethnicity associated with early onset puberty? (2) Are adiposity and/or psychosocial stress associated with observed associations?

DESIGN

Longitudinal data on 5839 girls from the UK Millennium Cohort Study were used to estimate associations between ethnicity, family income, adiposity and psychosocial stress with a marker of puberty.

MAIN OUTCOME MEASURE

Reported menstruation at age 11 years.

RESULTS

All quoted ORs are statistically significant. Girls in the poorest income quintile were twice as likely (OR=2.1), and the second poorest quintile nearly twice as likely (OR=1.9) to have begun menstruation compared with girls in the richest income quintile. Estimates were roughly halved on adjustment for Body Mass Index and markers of psychosocial stress (poorest, OR=1.5; second poorest, OR=1.5). Indian girls were over 3 times as likely compared with whites to have started menstruation (OR=3.5) and statistical adjustments did not attenuate estimates. The raised odds of menstruation for Pakistani (OR=1.9), Bangladeshi (OR=3.3) and black African (OR=3.0) girls were attenuated to varying extents, from about a third to a half, on adjustment for income and adiposity.

CONCLUSIONS

In contemporary UK, excess adiposity and psychosocial stress were associated with social inequalities in early puberty, while material disadvantage and adiposity were linked to ethnic inequalities in early puberty among girls.

Secular trends in menarcheal age in India-evidence from the Indian human development survey

BACKGROUND

Evidence from a number of countries in Europe and North America point towards the secular declining trend in menarcheal age with considerable spatial variations over the past two centuries. Similar trends were reported in several developing countries from Asia, Africa and Latin America. However, data corroborating any secular trend in the menarcheal age of the Indian population remained sparse and inadequately verified.

METHODS

We examined secular trends, regional heterogeneity and association of socioeconomic, anthropometric and contextual factors with menarcheal age among ever-married women (15-49 years) in India. Using the pseudo cohort data approach, we fit multiple linear regression models to estimate secular trends in menarcheal age of 91394 ever-married women using the Indian Human Development Survey.

RESULTS

The mean age at menarche among Indian women was 13.76 years (95 % CI: 13.75, 13.77) in 2005. It declined by three months from 13.83 years (95% CI: 13.81, 13.85) among women born prior to 1955-1964, to nearly 13.62 years (95% CI: 13.58, 13.67) among women born during late 1985-1989. However, these aggregate national figures mask extensive spatial heterogeneity as mean age at menarche varied from 15.0 years in Himachal Pradesh during 1955-1964 (95% CI: 14.89-15.11) to about 12.1 years in Assam (95% CI: 11.63-12.56) during 1985-1989.

CONCLUSION

The regression analysis established a reduction of nearly one month per decade, suggesting a secular decline in age at menarche among Indian women. Notably, the menarcheal age was significantly associated with the area of residence, geographic region, linguistic groups, educational attainment, wealth status, caste and religious affiliations among Indian women.

Early onset of puberty in young girls: an Italian cross-sectional study

BACKGROUND

International literature and clinical practice have referred to Marshall and Tanner data to define the physiological age at onset of puberty. A study in the United States (1997) showed an anticipation in pubertal onset, whereas several European studies did not confirm this trend.

AIM

To describe the onset of secondary sexual characteristics in a large Italian population of girls and to compare it to reference literature data.

SUBJECTS AND METHODS

A cross-sectional study on 7311 2-14-yr-old girls who spontaneously requested a clinical evaluation for routine health check-up or acute illness by family pediatrician's offices in a northern Italian region (Lombardy), between September 2005 and November 2006. Trained family pediatricians performed a complete physical examination; pubertal status was evaluated following Tanner's criteria; breast development was assessed by palpation.

RESULTS

Mean age of thelarche (B2), pubarche (PH2), menarche were 9.75, 10.09, and 12.49 yr, respectively. The prevalence of B2 and PH2 at ages 7-7.99 was 5.9% and 5.6%, respectively, at ages 8-8.99 was 15.5% and 13.8%, respectively. Mean time lapse from B2 to B3 and B2 to menarche was 1.46 and 2.74 yr, respectively. Mean age at menarche of our population and their respective mothers was almost identical.

CONCLUSIONS

Our population presented earlier clinical signs of pubertal development than those defined by Marshall and Tanner. Mean age of menarche was not different in comparison to the previous generation. A different progression of pubertal development was found, in which the shift to B3 may have more clinical relevance.

Determinants of age at menarche and time to menstrual cycle regularity in the French E3N cohort

PURPOSE

Early menarche has been associated with a greater risk of several major chronic diseases. Although largely genetically determined, age at menarche also has been related to environmental and lifestyle factors.

METHODS

Using linear regression models, we explored simultaneously several pre- and postnatal factors as potential determinants of age at menarche and time to menstrual cycle regularity in 96,493 women participating, since 1990, in the French E3N prospective cohort.

RESULTS

Younger age at recruitment, greater father's income index, urban birth place, greater birth length, and larger body silhouette during childhood were associated with an earlier age at menarche (from -1.3 to -4.6 months, P(trend) < .0001) whereas greater family size, food deprivation during childhood, and greater birth weight resulted in a delayed menarche (from +1.5 months to +5.3 months, P(trend) < .0001). Father's income index, urban birth place, and prematurity predicted a shorter time to menstrual cycle regularity (from -1.1 to -1.9 months, P(trend) < .04), whereas birth cohort, larger body silhouette at menarche, and childhood exposure to passive smoking were associated with a longer time to menstrual cycle regularity (from +1.1 months to +8.6 months, P(trend) < .006).

CONCLUSIONS

Age at menarche and menstrual cycle regularity are significantly influenced by several individual, environmental and lifestyle factors.

Age at menarche and the evidence for a positive secular trend in urban South Africa

Menarcheal age was estimated for 287 (188 Black; 99 White) urban South African girls born in Soweto-Johannesburg in 1990. The median menarcheal age for Blacks was 12.4 years (95% confidence interval (CI) 12.2, 12.6) and 12.5 years (95% CI 11.7, 13.3) for Whites. Data from six studies of menarcheal age, including the current study, were analyzed to examine the evidence for a secular trend between 1956 and 2004 in urban South African girls. There was evidence of a statistically significant secular trend for Blacks, but not Whites. Average menarcheal age for Blacks decreased from 14.9 years (95% CI 14.8, 15.0) in 1956 to 12.4 years (95% CI 12.2, 12.6) in the current study, an average decline of 0.50 years per decade. Fewer data were available for Whites, but average menarcheal age decreased from 13.1 years (95% CI 13.0, 13.2) in 1977 to 12.5 years (95% CI 11.7, 13.3) in the current study, an average decline of 0.22 years per decade. The diminishing age at menarche and the current lack of difference between Blacks and Whites is probably reflective of the continuing nutritional and socio-economic transition occurring within South Africa.

Gendered dimensions of obesity in childhood and adolescence

Background

The literature on childhood and adolescent obesity is vast. In addition to producing a general overview, this paper aims to highlight gender differences or similarities, an area which has tended not to be the principal focus of this literature.

Methods

Databases were searched using the terms 'obesity' and 'child', 'adolescent', 'teenager', 'youth', 'young people', 'sex', 'gender', 'masculine', 'feminine', 'male', 'female', 'boy' and 'girl' (or variations on these terms). In order to limit the potential literature, the main focus is on other reviews, both general and relating to specific aspects of obesity.

Results

The findings of genetic studies are similar for males and females, and differences in obesity rates as defined by body mass index are generally small and inconsistent. However, differences between males and females due to biology are evident in the patterning of body fat, the fat levels at which health risks become apparent, levels of resting energy expenditure and energy requirements, ability to engage in certain physical activities and the consequences of obesity for the female reproductive system. Differences due to society or culture include food choices and dietary concerns, overall physical activity levels, body satisfaction and the long-term psychosocial consequences of childhood and adolescent obesity.

Conclusion

This review suggests differences between males and females in exposure and vulnerability to obesogenic environments, the consequences of child and adolescent obesity, and responses to interventions for the condition. A clearer focus on gender differences is required among both researchers and policy makers within this field.

Mental health of young people: a global public-health challenge

Mental disorders account for a large proportion of the disease burden in young people in all societies. Most mental disorders begin during youth (12-24 years of age), although they are often first detected later in life. Poor mental health is strongly related to other health and development concerns in young people, notably lower educational achievements, substance abuse, violence, and poor reproductive and sexual health. The effectiveness of some interventions for some mental disorders in this age-group have been established, although more research is urgently needed to improve the range of affordable and feasible interventions, since most mental-health needs in young people are unmet, even in high-income countries. Key challenges to addressing mental-health needs include the shortage of mental-health professionals, the fairly low capacity and motivation of non-specialist health workers to provide quality mental-health services to young people, and the stigma associated with mental disorder. We propose a population-based, youth focused model, explicitly integrating mental health with other youth health and welfare expertise. Addressing young people's mental-health needs is crucial if they are to fulfil their potential and contribute fully to the development of their communities.

Pubertal transitions in health

Puberty is accompanied by physical, psychological, and emotional changes adapted to ensure reproductive and parenting success. Human puberty stands out in the animal world for its association with brain maturation and physical growth. Its effects on health and wellbeing are profound and paradoxical. On the one hand, physical maturation propels an individual into adolescence with peaks in strength, speed, and fitness. Clinicians have viewed puberty as a point of maturing out of childhood-onset conditions. However, puberty's relevance for health has shifted with a modern rise in psychosocial disorders of young people. It marks a transition in risks for depression and other mental disorders, psychosomatic syndromes, substance misuse, and antisocial behaviours. Recent secular trends in these psychosocial disorders coincide with a growing mismatch between biological and social maturation, and the emergence of more dominant youth cultures.

Changing trends in sex specific prevalence rates for childhood asthma, eczema, and hay fever

Numerous surveys of school-aged children have shown increasing asthma prevalence with a less publicized but noticeable change in the male to female ratio. We sought to confirm this change in the sex ratio in four questionnaire-based surveys and investigate possible explanations. Identical questionnaire surveys were performed in 1989 (n=3,390), 1994 (n=4,047), 1999 (n=3,540) and 2004 (n=1,920) in school-children aged 9-11 years. Over these 15 years the male to female ratio (M:F) significantly narrowed for wheeze (1.34 to 0.98:1 P < 0.0002), for asthma (1.74 to 1.02:1 P < 0.0001), for eczema (1.42:1 to 0.81:1 P < 0.0001) and for hay fever (1.46 to 0.93:1 P < 0.0001). The diagnosis of asthma in children with wheeze was more commonly made in boys in 1989 relative risk RR 1.32 (1.12, 1.56), even in those with accompanying eczema and/or hay fever RR 1.20 (0.99, 1.45). By 2004 this sex bias in diagnosis was no longer present, RR 1.01 (0.91, 1.12) for wheeze and 1.02 (0.85, 1.21) for those with wheeze and eczema and/or hay fever. From 1989 to 2004 no significant difference in sex distribution changes between older and younger children occurred, making secular trends in the onset of puberty in females an unlikely contributory factor. The disappearance of the bias to diagnose asthma in symptomatic males but not in females may be partly responsible for the narrowing of the sex ratio, but other factors such as those enhancing the expression of asthma and atopy in females may also be implicated.

The relation between menarche and the age of first symptoms in a multiple sclerosis cohort

BACKGROUND

Previously, multiple sclerosis (MS) has been thought to be associated with changes in hormone levels. This study investigates the association between the age of menarche and the age of onset of the first symptoms of MS.

METHODS

A complete list of patients diagnosed with MS in the province of Newfoundland and Labrador was constructed. The age of menarche for our entire relapsing remitting female MS (RRMS) population was requested by mailout survey. Age of symptom onset was ascertained by chart review.

RESULTS

A 74% rate of return on the survey results was obtained (150 RRMS patients). A linear regression model demonstrated that the age of first symptoms increased by 1.16 years as the age of menarche increased by one year (R2 = 0.69, P = 0.04). Another analysis showed that the average age of first symptoms for women with reported menarche from 10 to 12 years was 28.96 years compared with 31.83 years for a reported menarche from 13 to 15 years, a significant difference (P = 0.047, t-test).

CONCLUSIONS

This study suggests that menarche may be related to the pathogenesis of MS.

Lessons from large population studies on timing and tempo of puberty (secular trends and relation to body size): the European trend

Ever since the publication of the first textbook on human growth by Johann Augustin Stoeller in 1729, temporal changes (or secular trends) in growth and pubertal maturation have been observed throughout the world. Data covering the longest time span are often reported from European populations. For example, in Norway and Denmark the age at menarche has fallen rapidly since the 19th century, by up to 12 months per decade. These changes have broadly paralleled increases in adult height in most European countries over the last century, with rates of around 10-30mm per decade. These secular trends are influenced by background ethnic, geographical and socio-economic factors, and clearly nutritional changes have an important role as reflected by positive correlations between age at puberty onset or age at menarche and childhood body size. Changes in height, pubertal maturation, and childhood body size have all also been related to rate of weight gain in infancy, and there is growing evidence to suggest that this early postnatal period may represent an early window of susceptibility to long-term 'programming' of various outcomes in humans. There is debate as to whether the secular trends in pubertal maturation are continuing or have reached their limit. Even where temporal changes are overall clearly significant, they are most marked in the more nutritionally deprived sub-groups. Whether over-nutrition and increasing childhood obesity will continue to lead earlier puberty is uncertain. The confirmation of an estimated advance in the age at menarche of 6-12 months per 100 years will require a long-term perspective on behalf of current investigators, and new consideration of methodological approaches in an age of increasing recognition of children's rights for privacy.

Effects of obesity on growth and puberty

Nutrition is an important regulator of the tempo of human growth. Infancy may represent a critical "window" where variations in nutrition have longer-term consequences for growth and development. Rapid weight gain during infancy is associated with accelerated growth and early pubertal development. Rapid weight gain in infancy is also associated with the development of insulin resistance and an exaggerated adrenarche. Such circulating hormonal changes, together with elevated leptin levels and integral effects of fat cells on hormone action through local 11beta-steroid dehydrogenase and aromatase activity could effect rate of progression of pubertal development in obese subjects. The secular trends in growth and maturation are partly attributed to changing nutrition. Recent data suggest that age at menarche may be static, but there is a debate as to whether the first signs of puberty are being seen much earlier in obese girls. Rapid early weight gain, obesity and early development may have implications for later health through the development of PCOS and overall association with cancer risk.

Effects of environmental agents on the attainment of puberty: considerations when assessing exposure to environmental chemicals in the National Children's Study

The apparent decline in the age at puberty in the United States raises a general level of concern because of the potential clinical and social consequences of such an event. Nutritional status, genetic predisposition (race/ethnicity), and environmental chemicals are associated with altered age at puberty. The Exposure to Chemical Agents Working Group of the National Children's Study (NCS) presents an approach to assess exposure for chemicals that may affect the age of maturity in children. The process involves conducting the assessment by life stages (i.e., in utero, postnatal, peripubertal), adopting a general categorization of the environmental chemicals by biologic persistence, and collecting and storing biologic specimens that are most likely to yield meaningful information. The analysis of environmental samples and use of questionnaire data are essential in the assessment of chemicals that cannot be measured in biologic specimens, and they can assist in the evaluation of exposure to nonpersistent chemicals. Food and dietary data may be used to determine the extent to which nutrients and chemicals from this pathway contribute to the variance in the timing of puberty. Additional research is necessary in several of these areas and is ongoing. The NCS is uniquely poised to evaluate the effects of environmental chemicals on the age at puberty, and the above approach will allow the NCS to accomplish this task.

Maternal age of menarche is not associated with asthma or atopy in prepubertal children

BACKGROUND

Maternal sex hormones in pregnancy can theoretically influence the developing fetal immune system and modulate the subsequent development of atopic disorders. Early onset of menarche has been linked to increased oestrogen levels in adult women. A study was undertaken to examine the association between early onset menarche in pregnant women and asthma and atopic status of their children at 7 years of age.

METHODS

The Avon Longitudinal Study of Parents and Children (ALSPAC) is a longitudinal birth cohort study in which pregnant women, resident in Avon (UK), were recruited on the basis of an expected date of delivery between 1 April 1991 and 31 December 1992. Maternal age at menarche was assessed from prenatal questionnaires administered to the women. Clinical outcomes in the children were based on mothers' responses to self-completion questionnaires and included asthma, eczema, and hay fever. The atopic status of the child was objectively assessed by skin prick tests to a panel of common aeroallergens at the age of 7 years. Analyses used multivariable logistic regression with a diverse range of possible confounders.

RESULTS

Complete data were available on 5765 woman and child pairs. The prevalence of ever reported asthma to 7 years was 20.4%, eczema 58.6%, hay fever 12.1%, and atopy (defined as any positive (>2 mm weal) response) was present in 20.6%. There were no significant differences in mean age of menarche between mothers of children with and without each of the primary outcomes. Adjusted odds ratios (95% CI) for the latest age of menarche (16+ years) compared with the lowest (<12 years) reference group were 1.41 (1.00 to 1.99) for asthma, 0.98 (0.73 to 1.91) for eczema, 0.95 (0.62 to 1.44) for hay fever, and 0.98 (0.68 to 1.42) for atopy.

CONCLUSION

No consistent association was found between maternal age at menarche and asthma, eczema, hay fever or atopy in their children during early childhood.

Ethnicity, socio-economic status, overweight and underweight in East London adolescents

BACKGROUND

The developed world is experiencing an 'epidemic' of childhood obesity but little is known about the prevalence of obesity, or underweight, amongst adolescents from minority ethnic groups in the UK. An understanding of the prevalence of obesity and overweight in these populations is important since some ethnic groups may be particularly vulnerable to the adverse health effects associated with obesity.

STUDY OBJECTIVES

To examine levels of extreme obesity, obesity, overweight and underweight amongst a representative sample of adolescents from different ethnic groups in East London and to explore the association between socio-economic status and body mass index (BMI).

DESIGN

A school-based survey of adolescents aged 11-14. Obesity and overweight were estimated using the 1990 UK growth reference (UK 90) and the International Obesity Task Force (IOTF) cut-off points. Extreme obesity was defined as a BMI more than three SD above the UK 90 mean. Underweight was examined by looking at those with a BMI below the 15th or the 5th UK 90 percentiles.

MAIN RESULTS

A total of 2,482 adolescents were surveyed (response rate 84%), 73% from non-white ethnic groups. Although there were significant differences in BMI between ethnic groups, high levels of overweight were seen in all ethnic groups. More than one-third were overweight and one-fifth were obese using the UK 90; and over a quarter were overweight and almost one-tenth were obese using the IOTF cut-offs. Two per cent were extremely obese. Indian males were at higher risk of being overweight than white British males. The prevalence of obesity and overweight was similar in white British and Bangladeshi males. Overall the prevalence of underweight was slightly lower than that predicted by the UK 90, but South Asian ethnic groups, especially males, had a higher prevalence of underweight than other groups. No associations between BMI and measures of socio-economic status were found in this relatively deprived population.

CONCLUSIONS

The 'epidemic' of childhood obesity observed in the UK involves adolescents from all ethnic groups, although there are some differences between ethnic groups in the prevalence of overweight. Indian males appear to be at increased risk of being overweight. There is no evidence of a simultaneous increase in underweight amongst this population overall, but Bangladeshi, Indian and Pakistani boys appear to be at increased risk of being underweight.

Selecting girls with precocious puberty for brain imaging: validation of European evidence-based diagnosis rule

OBJECTIVES

To test the sensitivities of recently published American recommendations predicting occult intracranial lesion (OICL) in girls with central precocious puberty (CPP), and to validate a previously derived diagnosis rule predicting OICL based on age at puberty onset and estradiol (E2) level.

STUDY DESIGN

A retrospective, multicenter, hospital-based, cohort study was performed, including all girls with CPP seen in 7 centers in 6 European countries during given periods. American recommendations and the previously derived diagnosis rule were tested.

RESULTS

Girls with CPP (n=443), including 35 with OICL, were recruited. American recommendations did not identify all OICL. Previously identified independent risk factors for OICL were confirmed: age <6 years (adjusted odds ratio 20.5; 95% CI, 8.1-52.1) and E2 >45th percentile (3.0; 95% CI, 1.3-7.1). The previously derived diagnosis rule had 100% sensitivity (95% CI, 90-100): all girls with OICL had either an age <6 years or an E2 level >45th percentile. The specificity was 39% (95% CI, 34-44).

CONCLUSIONS

American recommendations do not seem safe to select European girls with CPP who require brain imaging. In settings where systematic brain imaging is not possible, the proposed diagnosis rule could safely help to avoid more than one third of unnecessary brain imaging.

Update on female pubertal development

PURPOSE OF REVIEW

To elucidate recent findings regarding female puberty. The successful completion of puberty is a prerequisite for reproduction. Many later disorders of fertility and metabolism may develop during puberty. New more sensitive and specific assays provided us with possibilities for a better understanding of the process of puberty, and the discovery of new factors such as leptin evoked the hope of finding key regulators of the onset of puberty.

RECENT FINDINGS

The secular trend towards earlier menarche appears now to have come to an end, but discussions about changes in the age of pubertal onset still continue. In a few detected cases of leptin mutations puberty has not occurred spontaneously. The intact secretion of leptin seems to be a necessary prerequisite for the onset of puberty. Apart from that, recent research has indicated that leptin levels mainly reflect body composition. Leptin as well as gonadotropins, steroids and growth hormone shows specific circadian patterns. The 24 h pattern of leptin is similar before and after puberty, but the 24 h pattern of the other hormones changes. The serum concentration of inhibin B increases in the years preceding puberty and in early puberty, whereas inhibin A increases in mid to late puberty.

SUMMARY

The biological significance of the changing circadian patterns remains to be determined. Inhibin B serum concentrations together with follicle-stimulating hormone may indicate remaining potential ovarian activity during childhood in, for example, patients with Turner syndrome, but more information and other possible markers are needed.