Reference data for testicular volume measured with ultrasound and pubic hair in Norwegian boys are comparable with Northern European populations

Pubertal testicular volume references for ruler, orchidometer, and ultrasonography measurements based on a longitudinal follow-up

BACKGROUND

Testicular volume is a marker of male pubertal development. Various clinical conditions and their treatments may influence testicular growth.

OBJECTIVES

To create ruler-based age-dependent pubertal testicular volume references that enable calculation of standard deviation (SD) scores.

MATERIALS AND METHODS

Study cohort comprised 65 boys who attended clinical examination twice a year from the age of 8.5 years until the attainment of final testicular size. Forty-nine (75.4%) boys completed the follow-up and 16 (24.6%) boys dropped out before the attainment of final post-pubertal testicular size. At each follow-up visit testicular size was measured with a ruler, orchidometer, and ultrasonography. LMS or LMSP method served as the technique for creating reference growth curves for testicular volumes. Using the novel references for ruler measurements, development of SD scores was assessed in a cohort of boys with unilateral cryptorchidism.

RESULTS

Reference growth curves were constructed separately for ruler, orchidometer, and ultrasonography measurements. Median orchidometer volume of 4 mL, marker of male pubertal onset, occurred at the age of 11.7 years, whereas +2SD curve surpassed 4 mL at 10.2 years and -2SD curve at 13.7 years. Modeled ages at the attainment of 4 mL testicular volume based on ruler measurements were 9.7 years for +2SD curve, 11.5 years for median curve, and 13.6 years for -2SD curve. Ultrasonography-based volume of 1.3 mL corresponded with the median modeled orchidometer-based volume of 4 mL. In boys with unilateral cryptorchidism, ruler-based SD scores decreased during puberty in undescended testes, but not in descended testes.

DISCUSSION AND CONCLUSION

The present study provides reference values for pubertal testicular volume measured with a ruler enabling an age-dependent assessment of testicular size. Comparison with measurements by an orchidometer and ultrasonography is also presented.

Exposure to Per- and Polyfluoroalkyl Substances and Timing of Puberty in Norwegian Boys: Data from the Bergen Growth Study 2

Per- and polyfluoroalkyl substances (PFAS) are widespread environmental contaminants with endocrine-disruptive properties. Their impact on puberty in boys is unclear. In this cross-sectional study, we investigated the association between PFAS exposure and pubertal timing in 300 Norwegian boys (9-16 years), enrolled in the Bergen Growth Study 2 during 2016. We measured 19 PFAS in serum samples and used objective pubertal markers, including ultrasound-measured testicular volume (USTV), Tanner staging of pubic hair development, and serum levels of testosterone, luteinizing hormone, and follicle-stimulating hormone. In addition to logistic regression of single pollutants and the sum of PFAS, Bayesian and elastic net regression were used to estimate the contribution of the individual PFAS. Higher levels of the sum of perfluorooctanesulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), and perfluorohexanesulfonic acid (PFHxS) were associated with later pubertal onset according to USTV (age-adjusted odds ratio (AOR): 2.20, 95% confidence interval (CI): 1.29, 3.93) and testosterone level (AOR: 2.35, 95% CI: 1.34, 4.36). Bayesian modeling showed that higher levels of PFNA and PFHxS were associated with later pubertal onset by USTV, while higher levels of PFNA and perfluoroundecanoic acid (PFUnDA) were associated with later pubertal onset by testosterone level. Our findings indicate that certain PFAS were associated with delay in male pubertal onset.

Cryptorchidism and puberty

Cryptorchidism is the condition in which one or both testes have not descended adequately into the scrotum. The congenital form of cryptorchidism is one of the most prevalent urogenital anomalies in male newborns. In the acquired form of cryptorchidism, the testis that was previously descended normally is no longer located in the scrotum. Cryptorchidism is associated with an increased risk of infertility and testicular germ cell tumors. However, data on pubertal progression are less well-established because of the limited number of studies. Here, we aim to review the currently available data on pubertal development in boys with a history of non-syndromic cryptorchidism-both congenital and acquired cryptorchidism. The review is focused on the timing of puberty, physical changes, testicular growth, and endocrine development during puberty. The available evidence demonstrated that the timing of the onset of puberty in boys with a history of congenital cryptorchidism does not differ from that of non-cryptorchid boys. Hypothalamic-pituitary-gonadal hormone measurements showed an impaired function or fewer Sertoli cells and/or germ cells among boys with a history of cryptorchidism, particularly with a history of bilateral cryptorchidism treated with orchiopexy. Leydig cell function is generally not affected in boys with a history of cryptorchidism. Data on pubertal development among boys with acquired cryptorchidism are lacking; therefore, more research is needed to investigate pubertal progression among such boys.

Inter-individual exposure variability interpretation through reflection of biological age algorithm in physiologically based toxicokinetic model: Application to human risk assessment of di-isobutyl-phthalate

Age-related changes and interindividual variability in the degree of exposure to hazardous substances in the environment are pertinent factors to be considered in human risk assessment. Existing risk assessments remain in a one-size-fits-all approach, often without due consideration of inter-individual toxicokinetic variability factors, such as age. The purpose of this study was to advance from the existing risk assessment of hazardous substances based on toxicokinetics to a precise human risk assessment by additionally considering the effects of physiologic and metabolic fluctuations and interindividual variability in age. Qualitative age-associated physiologic and metabolic changes in humans, obtained through a meta-analysis, were quantitatively modeled to produce the final biological age algorithm (BAA). The developed BAAs (for males) were extended and applied to the reported testicular reproductive toxicity-focused di-isobutyl-phthalate (DiBP)-mono-isobutyl-phthalate (MiBP) physiologically based toxicokinetic (PBTK) model in males. The advanced PBTK model combined with the BAA was applied to the human risk assessment based on MiBP biomonitoring data. As a result, the specialized DiBP external exposure values for each age could be estimated. Additionally, by applying the Monte Carlo simulation, the distribution of internal exposure diversity among individuals according to the same external exposure dose could be estimated. The contributions of physiologic and metabolic factors to the age-dependent toxicokinetic changes were approximately 93.41-99.99 and 0.01-6.59%, respectively. In addition, the relative contribution of metabolic factors was major in infants and continued to decrease as age increased (up to about age 30 years). This study provides a step-by-step platform that can be widely applied to overcome the limitations of existing toxicokinetic models that still require interindividual pharmacokinetic variability explanations. This will be important for the rationalization and explanation of inter-individual variability in the pharmacokinetics of many substances.

Mini review shows that a testicular volume of 3 mL was the most reliable clinical sign of pubertal onset in males

AIM

We aimed to evaluate aspects of pubertal development to identify the most reliable clinical sign of pubertal onset in males.

METHODS

We performed a mini review of the literature.

RESULTS

In 1951 Reynolds and Wines categorised pubic hair growth and genital development in five stages by visual inspection. Today the Tanner scale is used to assess the five stages of pubertal development, The second genital stage, characterised by enlargement of the scrotum defines pubertal onset in males. Testicular volume may be evaluated by using a calliper or by ultrasound scan. The Prader orchidometer, described in 1966, offers a method for evaluating testicular growth by palpation. Pubertal onset is commonly defined as testicular volume >3 or ≥4 mL. The development of sensitive laboratory methods has enabled studies analysing hormonal activity in the hypothalamus-pituitary-gonadal axis. We review the relationships between physical and hormonal signs of puberty. We also discuss the results of studies assessing different aspects of pubertal development with a focus on identifying the most reliable clinical sign of pubertal onset in males.

CONCLUSION

A substantial amount of evidence supports testicular volume of 3 mL as the most reliable clinical sign of male pubertal onset.

The relationship between ultrasonographically measured testicular volumes and cord blood inhibin B concentrations in healthy term male neonates

Serum inhibin B (INHB) concentrations are associated with testicular volumes (TV) in all periods of childhood. The aim of the study was to investigate the relationship between TV measured by ultrasonography (US) and cord blood inhibin B and total testosterone (TT) concentrations, stratified by mode of delivery. In total 90 male infants were included. Testes of healthy, term newborns were evaluated by US on the third day after delivery. TV were calculated using two formulae: The ellipsoid formula [length (mm) × width (mm2) × π/6] and Lambert formula [length (mm) x width (mm) x height (mm) x 0.71]. Cord blood was taken for the determination of total testosterone (TT) and INHB. TT and INHB concentrations were evaluated according to TV percentiles (<10th, 10th-90th, >90th). There was a strong positive correlation between mean TV calculated with both formulae by percentile group (r = 0.777, r = 0.804, r = 0.846; p < 0.001). Cord blood INHB, but not TT were significantly lower in newborns with TV < 10th percentile compared to those with TV between 10 and 90th percentile and > 90th percentile (p < 0.05). There was a positive correlation between left and right TV calculated by either formula, and cord blood INHB (r = 0.212, 0.313, 0.320, 0.246,p < 0.05), not TT. There was no significant difference between hormones and TV when grouped by mode of delivery (p > 0.05). The Lambert and ellipsoid formulas are equally reliable in calculating neonatal testicular by ultrasound. INHB concentration is high in cord blood and positively correlated with neonatal TV. Cord blood INHB concentration may be an indicator for early detection of testicular structure and function disorders in neonates.

Young athlete's growing heart: sex differences in cardiac adaptation to exercise training during adolescence

BACKGROUND

Athlete's heart is a condition of exercise-induced cardiac remodelling. Adult male endurance athletes more often remodel beyond reference values. The impact of sex on remodelling through adolescence remains unclear. Paediatric reference values do not account for patient sex or exercise history. We aimed to study the effect of sex on cardiac remodelling throughout adolescence.

METHODS

We recruited 76 male (M) and female (F) 12-year-old cross-country skiers in a longitudinal cohort study. Echocardiography was performed and analysed according to guidelines at age 12 (48 M, 28 F), 15 (34 M, 14 F) and 18 (23 M, 11 F). Repeated echocardiographic measurements were analysed by linear mixed model regression.

RESULTS

Males displayed greater indexed left ventricular end-diastolic volumes (LV EDVi) from age 12 (M 81±7 vs F 76±7, mL/m², p≤0.01), and progressed further until follow-up at age 18 (M 2.3±9.7 vs F -3.9±4.5 ΔmL/m², p≤0.01). LV EDVi remained above adult upper reference values in both groups. Males increased LV Mass Index from age 12 to 18 (M 33±27 vs F 4±19, Δg/m², p≤0.01). Males displayed LV mass above paediatric reference values at ages 15 and 18. A subset of males (35%) and females (25%) displayed wall thickness above paediatric reference values at age 12. Cardiac function was normal. There was no sex difference in exercise hours.

CONCLUSION

Sex-related differences in athlete's heart were evident from age 12, and progressed throughout adolescence. Remodelling beyond reference values was more frequent than previously reported, particularly affecting males. Age, sex and exercise history may assist clinicians in distinguishing exercise-induced remodelling from pathology in adolescents.

Increase in peak oxygen uptake and Andersen test performance in children from age six to ten: The Health Oriented Pedagogical Project (HOPP)

The increased prevalence of non-communicable disease risk factors among children because of lack of physical activity is concerning. The Health Oriented Pedagogical Project was set up to combine learning activities and physical activity, thus reducing sedentariness during school time. The current study aimed to measure and describe the longitudinal and cross-sectional development of oxygen uptake and running performance in children at ages six and ten. The validity of the Andersen Test in predicting V̇O2peak in these age groups was also evaluated. Eighty-six children (53 boys, 33 girls) with complete datasets at ages 6 and 10 years were included in the longitudinal study, while 192 children (106 boys, 86 girls) were included in the cross-sectional analysis because they missed data from 1 year. Oxygen uptake was measured using a metabolic analyser and maximal treadmill running, while the distance covered during the AT determined running performance. Body mass, height, and waist-to-height ratios were recorded. Multiple regression analysis was used to assess the association between oxygen uptake and running performance. The cross-sectional results did not differ from the longitudinal data for anthropometrical data, oxygen uptake and running performance. Height, body mass and waist-to-height ratio did not differ between the sexes at ages six or ten. Boys had significantly higher peak oxygen uptake than girls at 6 years of age, irrespective of how oxygen uptake was expressed. Allometric scaling of oxygen uptake revealed differences between sexes at both ages. Longitudinal running performance increased in both sexes from 6 to 10 years. Boys ran significantly longer only at age ten. The association between oxygen uptake and running performance varied according to how the oxygen uptake was expressed and with sex and age. Ten-year-old girls had the highest correlations in the longitudinal investigation, from r2 = 0.48 (fV̇O2peak) to 0.65 (rV̇O2peak) between AT and V̇O2peak. The AT was found to be as valid as the 20-m shuttle run test in estimating peak oxygen uptake, with a random measurement error of approximately 11% of mean values.

Observer agreement of imaging measurements used for evaluation of dentofacial deformity in juvenile idiopathic arthritis

OBJECTIVES

To examine the precision of imaging measures commonly used to assess mandibular morphology in children and adolescents with juvenile idiopathic arthritis (JIA). Secondly, to compare cone-beam computed tomography (CBCT) and magnetic resonance imaging (MRI) in the measurement of condylar height.

METHODS

Those included were children diagnosed with JIA during 2015-18 who had had an MRI, a CBCT of the temporomandibular joints (TMJs) and a lateral cephalogram (ceph) of the head within one month of each other. Agreement within and between observers and methods was examined using Bland-Altman mean-difference plots and 95% limits of agreement (LOA). A 95% LOA within 15% of the sample mean was considered acceptable. Minimal detectable change (MDC) within and between observers was estimated.

RESULTS

90 patients (33 males) were included, with a mean age of 12.8 years. For MRI, intra- and interobserver 95% LOA were relatively narrow for total mandibular length: 9.6% of the sample mean. For CBCT, condylar height, both intra- and interobserver 95% LOA were wide: 16.0 and 28.4% of the sample mean, respectively. For ceph, both intra- and interobserver 95% LOA were narrow for the SNA-angle and gonion angle: 5.9 and 8% of the sample mean, and 6.2 and 6.8%, respectively.

CONCLUSIONS

We have identified a set of precise measurements for facial morphology assessments in JIA, including one MRI-based (total mandibular length), one CBCT-based (condylar height), and three ceph-based. Condylar height was higher for MRI than for CBCT; however, the measurement was too imprecise for clinical use. MDC was also determined for a series of measurements.

Reference Curves for Pediatric Endocrinology: Leveraging Biomarker Z-Scores for Clinical Classifications

CONTEXT

Hormone reference intervals in pediatric endocrinology are traditionally partitioned by age and lack the framework for benchmarking individual blood test results as normalized z-scores and plotting sequential measurements onto a chart. Reference curve modeling is applicable to endocrine variables and represents a standardized method to account for variation with gender and age.

OBJECTIVE

We aimed to establish gender-specific biomarker reference curves for clinical use and benchmark associations between hormones, pubertal phenotype, and body mass index (BMI).

METHODS

Using cross-sectional population sample data from 2139 healthy Norwegian children and adolescents, we analyzed the pubertal status, ultrasound measures of glandular breast tissue (girls) and testicular volume (boys), BMI, and laboratory measurements of 17 clinical biomarkers modeled using the established "LMS" growth chart algorithm in R.

RESULTS

Reference curves for puberty hormones and pertinent biomarkers were modeled to adjust for age and gender. Z-score equivalents of biomarker levels and anthropometric measurements were compiled in a comprehensive beta coefficient matrix for each gender. Excerpted from this analysis and independently of age, BMI was positively associated with female glandular breast volume (β = 0.5, P < 0.001) and leptin (β = 0.6, P < 0.001), and inversely correlated with serum levels of sex hormone-binding globulin (SHBG) (β = -0.4, P < 0.001). Biomarker z-score profiles differed significantly between cohort subgroups stratified by puberty phenotype and BMI weight class.

CONCLUSION

Biomarker reference curves and corresponding z-scores provide an intuitive framework for clinical implementation in pediatric endocrinology and facilitate the application of machine learning classification and covariate precision medicine for pediatric patients.

Ultrasonographic measurements of the testicular volume in Turkish boys aged 0-8 years and comparison with international references

OBJECTIVES

Proper diagnosis and follow-up of children with testicular disorders depend on the presence of adequate references for testicular volume. The objective of this study was to determine the testicular volume by ultrasound in Turkish boys aged between 0 and 8 years.

METHODS

A total of 320 boys with bilaterally descended testes underwent scrotal ultrasound examinations. The testicular volume (mL) was calculated by the empirical formula of Lambert (V=L × T × AP × 0.71) and the formula for an ellipsoid (V=L × T × AP × π/6). The testicular volume was compared with children's age, and Z-score data for weight, height, and BMI. The age-specific 3rd, 10th, 25th, 50th, 75th, 90th, and 97th percentiles of the testicular volume were produced and compared with the international references.

RESULTS

The median (IQR) volume of the right and left testis were 0.75 (0.57-0.99) and 0.72 (0.56-0.98) mL (formula of Lambert), respectively; and 0.56 (0.42-0.73) and 0.53 (0.41-0.72) mL, (formula for an ellipsoid), respectively. The age-specific median of the average volume of the right and left testis estimated by the Lambert equation in the first five years was measured between 0.63 and 0.71 mL, followed by an increase to about 1.31 mL at the age of 8. This increase was highly statistically significant (p<0.0001). No significant association was found between the Z-scores for weight, height, and BMI of boys and the testicular volumes.

CONCLUSIONS

This study provides the first national ultrasound-based estimates for testicular volume in Turkish boys aged 0-8 years.

Varicocelectomy in adolescents - Does it safeguard future fertility? A single centre experience

BACKGROUND

There is paucity of literature comparing varicocelectomy to observant management amongst adolescent boys with hormonal and semen abnormalities resulting from high grade unilateral varicoceles and consequent testicular volume loss. Furthermore, it is not known whether surgical correction in such adolescents improves paternity rates in future compared to their non-operated cohort.

OBJECTIVE

The primary objective was to compare adolescent boys with unilateral high grade varicocele with associated ipsilateral testicular volume loss who were operated versus those who were not, in relation to their fertility markers (hormonal, semen parameters, and testicular volume) over a 5 year follow up period. The secondary objective was to compare the paternity rates in the respective groups over long term.

STUDY DESIGN

This was a single center, retrospective study of a prospectively maintained database conducted from 2010 to 2020, based on a standardized protocol. All adolescent boys >15 years of age (middle and late adolescence), with grade II or III unilateral varicoceles with abnormal fertility markers, who were operated (Group A) and not operated (Group B) were included. The changes in hormonal assay, sonographic assessment, semen analysis at presentation, 1st year and the 5th year follow up amongst both the groups were collated and analysed. Primary paternity rates amongst both the groups was documented by telephonic or email conversations.

RESULTS

Of the 182 boys referred for varicocele management, 110 boys (Group A -70 boys and Group B - 40 boys) satisfied our inclusion criteria and were analysed. Mean age at presentation amongst Group A boys was 16.5 years (15-18 years) and Group B boys was 16 years (15-18 years). Grade III varicoceles were more predominant amongst both the groups. There was a significant improvement in all Group A boys (operated) in the fertility markers from the time at presentation to the 5th year follow up (p < 0.001). In Group B, (boys not operated) there was no significant improvement in the above parameters. The testicular catch up growth was 92% at the 5th year follow-up in Group A and 42% in Group B. At long term follow-up, the paternity rate was 80% and 36% in Group A and B respectively.

DISCUSSION AND CONCLUSION

In adolescent boys in whom hormonal assay, testicular volumes and semen characteristics are negatively affected by high grade unilateral varicoceles, surgical correction could normalize these values, thereby safeguarding their fertility in the long term.

Maternal PCOS status and metformin in pregnancy: Steroid hormones in 5-10 years old children from the PregMet randomized controlled study

Objective

Polycystic ovary syndrome (PCOS) is a common endocrine disorder, with potential effects on offspring both genetically and through altered intrauterine environment. Metformin, which ameliorate hormonal disturbances in non-pregnant women with PCOS is increasingly used in pregnancy. It passes the placenta, and the evidence on potential consequences for offspring endocrine development is scarce. We explore the potential effects of maternal PCOS status and intrauterine metformin exposure on offspring steroid hormone levels.

Design

This is a follow-up study of 5–10 years old children from the PregMet-study–a randomized controlled trial comparing metformin (2000 mg/day) to placebo during PCOS pregnancies. Of the 255 children invited, 117 (46%) were included.

Methods

There was no intervention in this follow-up study. Outcomes were serum levels of androstenedione, testosterone, SHBG, cortisol, 17-hydroxyprogesterone, 11-deoxycortisol and calculated free testosterone converted to gender-and age adjusted z-scores from a Norwegian reference population. These were compared in i) placebo-exposed children versus children from the reference population (z-score zero) by the deviation in z-score by one-sample t-tests and ii) metformin versus placebo-exposed children by two-sample t-tests. Holm-Bonferroni adjustments were performed to account for multiple endpoints.

Results

Girls of mothers with PCOS (n = 30) had higher mean z-scores of androstenedione (0.73 (95% confidence interval (CI) 0.41 to 1.06), p<0.0001), testosterone (0.76 (0.51 to 1.00), p<0.0001), and free testosterone (0.99 (0.67 to 1.32), p<0.0001) than the reference population. Metformin-exposed boys (n = 31) tended to have higher 11-deoxycortisol z-score than placebo-exposed boys (n = 24) (mean difference 0.65 (95% CI 0.14–1.17), p = 0.014).

Conclusion

Maternal PCOS status was associated with elevated androgens in 5- to 10-year-old daughters, which might indicate earlier maturation and increased risk of developing PCOS. An impact of metformin in pregnancy on steroidogenesis in children born to mothers with PCOS cannot be excluded. Our findings need confirmation in studies that include participants that have entered puberty.

Long-term follow-up of boys who have undergone a testicular biopsy for fertility preservation

STUDY QUESTION

What is the long-term reproductive health outcome of patients who have undergone testicular sampling for fertility preservation (FP) before and during the pubertal transition period?

SUMMARY ANSWER

In long-term follow-up after testicular sampling for FP, hormonal data showed that 33% of patients had primary seminiferous tubule insufficiency (high FSH) while semen analyses showed 52% of patients having a severe reduction in total sperm counts or complete absence of ejaculated sperm.

WHAT IS KNOWN ALREADY

During childhood and adolescence, both treatments for cancer and benign haematological diseases that require a bone marrow transplantation, can be detrimental to spermatogenesis by depleting the spermatogonial stem cell population. A testicular biopsy prior to chemotherapy or radiotherapy, even though still an experimental procedure, is now recommended for FP by European and USA oncofertility societies if performed within an institutional research setting. While short-term follow-up studies showed little to no post-operative complications and a normal testicular development after 1 year, data regarding the long-term follow-up of boys who have undergone this procedure are still lacking.

STUDY DESIGN, SIZE, DURATION

This is a longitudinal retrospective cohort study that reports on the long-term follow-up of pre- and peri-pubertal boys who have undergone a testicular biopsy for FP between May 2005 and May 2020. All the patients included in this study were referred to our programme by haematologists-oncologists who are part of a regional multi-centric collaborative care pathway.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Of the 151 boys referred to our FP programme, 139 parents/legal guardians accepted that their child undergo a testicular biopsy. Patient characteristics (i.e. age at biopsy, urogenital history, pubertal status at diagnosis), indications (disease type and dosage of gonadotoxic treatments), operative and post-operative data (biopsy volume, surgical complications), anatomopathological analyses (presence/absence of spermatogonia, Johnsen score) and reproductive data (semen analyses, FSH, LH, testosterone levels) were collected from the institutions' FP database and medical records or from the 'Brussels Health Network'. Cumulative alkylating agent treatment was quantified using the cyclophosphamide equivalent dose (CED). Patients who were 14 years or older at the time of the follow-up and in whom the testicular tissue was shown to contain spermatogonia were included in the reproductive outcome analysis. Comparison of the sperm count findings (absence/presence of spermatozoa) and FSH levels (high (≥10 IU/l)/normal) between patients who were either pre- (Tanner 1) or peri-pubertal (Tanner >1) at the time of the biopsy was done using the Mann-Whitney U or Fisher's tests. A multiple logistic regression was used to study the relationship between the hormone reproductive outcome (high versus normal FSH), as a proxy marker for fertility, and both the pubertal status (Tanner 1 versus Tanner >1) and Johnsen score at the time of the biopsy, while adjusting for CED.

MAIN RESULTS AND THE ROLE OF CHANCE

A testicular biopsy was performed in 139 patients either before (129/139) or after (10/139) the start of a gonadotoxic treatment. Post-operative complications occurred in 2.1% (3/139). At the time of the procedure, 88% (122/139) of patients were pre-pubertal and 12% (17/139) were peri-pubertal. The presence of spermatogonia was documented in 92% (128/139) of cases. Follow-up data were available for 114 patients after excluding 23 deceased and two patients lost to follow-up. A paediatric endocrinologist's follow-up including clinical examination and data on reproductive hormones was available for 57 patients (age ≥14) and 19 (33%) of these were found to have high FSH levels (20 ± 8.8 IU/l). There were 37 patients who had returned to the reproductive specialist's consultation for post-treatment fertility counselling and results on semen analysis were available in 27 of these cases; 14/27 (52%) had severely impaired semen parameters including 8 who were azoospermic. Among patients who received an alkylating agent-based treatment (n = 42), a peri-pubertal status (Tanner >1) at the time of diagnosis/biopsy was found to be associated with a higher risk of having primary testicular failure (defined by an FSH ≥ 10 IU/l) after treatment completion with an OR of 6.4 (95% CI 1.22-33.9; P = 0.03). Of all the patients, 2.6% had already fulfilled their wish to build a family or were actively seeking parenthood.

LIMITATIONS, REASONS FOR CAUTION

Although this is the largest cohort with follow-up data providing proxy markers of the reproductive potential of boys in whom a testicular biopsy for FP was performed before puberty or during the pubertal transition period, the amount of data provided is limited, and originating from a single programme. Further data collection to confirm the observations in other settings is therefore awaited.

WIDER IMPLICATIONS OF THE FINDINGS

Testicular sampling for FP should be offered to boys at risk of losing their fertility (and is recommended for those at high risk) as part of ethically approved research programmes. Long-term follow-up data on increasing numbers of boys who have undergone an FP procedure will help improve patient care in the future as patient-specific factors (e.g. urogenital history, age at gonadotoxic therapy) appear to influence their reproductive potential after gonadotoxic therapies.

STUDY FUNDING/COMPETING INTEREST(S)

FNRS-Télévie, the Salus Sanguinis Foundation and the Belgian Foundation against Cancer supported the studies required to launch the FP programme. The authors declare that they have no conflict of interest.

TRIAL REGISTRATION NUMBER

N/A.

Low BMI, but not high BMI, influences the timing of puberty in boys

BACKGROUND

Previous studies investigating the association between weight status and onset of puberty in boys have been equivocal. It is currently unclear to what extent weight class influences puberty onset and progression.

OBJECTIVES

To explore the relationship between degree of sexual maturation and anthropometric measures in Norwegian boys.

METHODS

The following endpoints were collected in a Norwegian cross-sectional study of 324 healthy boys aged 9-16: ultrasound-determined testicular volume (USTV), total serum testosterone, Tanner pubic hair stage, height, weight, waist circumference (WC), subscapular skinfolds (SSF), and body fat percentage (%BF). Testicular volume-for-age z-scores were used to classify "early," "average," or "late" maturing boys. Ordinal logistic regression analyses with a proportional odds model were applied to analyze the association between anthropometric variables and age-adjusted degree of pubertal development, with results expressed as age-adjusted odds ratios (AOR). Cumulative incidence curves for reaching pubertal milestones were stratified by BMI.

RESULTS

Boys with a low BMI for age (BMI_z  < -1) were less likely to have reached a pubertal testicular volume (USTV ≥ 2.7 mL) or a pubertal serum level of testosterone (≥0.5 nmol/L) compared to normal weight boys (AOR 0.3, p = 0.038, AOR 0.3, p = 0.026, respectively), and entered puberty on average with a delay of approximately eight months. Boys with high BMI for age (BMI_z  > 1) exhibited a comparable timing as normal weight boys. The same was found for WC. Pubertal markers were not associated with SSF or %BF.

CONCLUSION

By examining the association between puberty and weight status classified as low, average, or high, we found that a low BMI or WC for age were associated with a less advanced pubertal development and delayed timing of puberty in boys. No significant association was observed for a high BMI or WC. Moreover, no significant effects of SSF or %BF were observed. A low weight status should also be considered when assessing pubertal development in boys.

Referential Values of Testicular Volume Measured by Ultrasonography in Normal Children and Adolescents: Z-Score Establishment

Objective: To establish Z-score regression equation derived from age for testicular volume measured by ultrasonography in normal boys aged 0 to 18 years old. Method: The length (L), width (W), and height (H) of 3,328 testicles from 1,664 Chinese boys were measured by ultrasonography. Lambert's formula: L × W × H × 0.71 was used to calculate testicular volume. Z-score regression equation derived from age was established by regression analysis of predicted values of testicular volume and standard deviations. Result: There was no significant difference between left and right testicular volumes. Testicular volume was positively correlated with age, and logarithmic transformation of testicular volume can show a fine curve fit with age. To establish Z-score regression equation derived from age, the predicted values of testicular volume used cubic regression equations, and the standard deviation used square regression equations. The Z-score regression equation derived from age was calculated by the formula: z = [lg (L × W × H × 0.71) - (-0.3524-0.01759 × x+0.009417 × x2-0.0001840 × x3)]/(0.1059+0.01434 × x-0.0005324 × x2). Conclusion: The current study provided a reference value for testicular volume of boys aged 0 to 18 years old. Z-score regression equation derived from age for testicular volume can be established. Z-score will be of great value for the testicular development assessment and disease diagnosis and follow-up.