Global patterns in testicular cancer incidence and mortality in 2020

With 74 500 new cases worldwide in 2020, testicular cancer ranks as the 20th leading cancer type, but is the most common cancer in young men of European ancestry. While testicular cancer incidence has been rising in many populations, mortality trends, at least those in high-income settings, have been in decline since the 1970s following the introduction of platinum-based chemotherapy. To examine current incidence and mortality patterns, we extracted the new cases of, and deaths from cancers of the testis from the GLOBOCAN 2020 database. In 2020, testicular cancer was the most common cancer in men aged 15 to 44 in 62 countries worldwide. Incidence rates were highest in West-, North- and South-Europe and Oceania (age-standardised rate, ASR ≥7/100 000), followed by North America (5.6/100 000 and lowest (<2/100 000) in Asia and Africa. The mortality rates were highest in Central and South America (0.84 and 0.54 per 100 000, respectively), followed by Eastern and Southern Europe, and Western and Southern Africa. The lowest mortality rates were in Northern Europe, Northern Africa and Eastern Asia (0.16, 0.14, 0.9 per 100 000, respectively). At the country level, incidence rates varied over 100-fold, from 10/100 000 in Norway, Slovenia, Denmark and Germany to ≤0.10/100 000 in Gambia, Guinea, Liberia, Lesotho. Mortality rates were highest in Fiji, Argentina and Mexico. Our results indicate a higher mortality burden in countries undergoing economic transitions and reinforce the need for more equitable access to testicular cancer diagnosis and treatment globally.

O-228 The SSRI antidepressant Sertraline inhibits CatSper calcium channels in human sperm

Study question

Do Selective Serotonin Reuptake Inhibitor (SSRI) antidepressants affect the function of human sperm?

Summary answer

The SSRI-antidepressant Sertraline (e.g. Zoloft) inhibits the sperm-specific Ca2+ channel CatSper and affects human sperm function in vitro.

What is known already

In human sperm, CatSper translates changes of the chemical microenvironment into changes of the intracellular Ca2+ concentration ([Ca2+]i) and swimming behavior. CatSper is promiscuously activated by oviductal ligands, but also by synthetic chemicals that might disturb the fertilization process. It is well known that SSRIs have off-target actions on Ca2+, Na+, and K+ channels in somatic cells. Whether SSRIs affect the activity of CatSper is, however, unknown.

Study design, size, duration

We studied the action of the seven drugs belonging to the most commonly prescribed class of antidepressants, SSRIs, on resting [Ca2+]i and Ca2+ influx via CatSper in human sperm. The SSRI Sertraline was selected for in-depth analysis of its action on steroid-, prostaglandin-, pH-, and voltage-activation of human CatSper. Moreover, the action of Sertraline on sperm acrosomal exocytosis and penetration into viscous media was evaluated.

Participants/materials, setting, methods

The activity of CatSper was investigated in sperm of healthy volunteers, using kinetic Ca2+ fluorimetry and patch-clamp recordings. Acrosomal exocytosis was investigated using Pisum sativum agglutinin (PSA) and image cytometry. Sperm penetration in viscous media was evaluated using the Kremer test.

Main results and the role of chance

Four SSRIs increased [Ca2+]i, two out of which also attenuated ligand-induced Ca2+ influx via CatSper. In contrast, Sertraline decreased [Ca2+]i and almost completely suppressed ligand-induced Ca2+ influx via CatSper. Remarkably, the drug was about four-fold more potent to suppress prostaglandin- versus steroid-induced Ca2+ influx. Sertraline also suppressed alkaline- and voltage-activation of CatSper, indicating that the drug directly inhibits human CatSper. Finally, Sertraline suppressed ligand-induced acrosome reaction and sperm penetration into viscous media.

Limitations, reasons for caution

This is an in vitro study. Future studies have to assess the physiological relevance in vivo.

Wider implications of the findings

The off-target action of Sertraline on CatSper in human sperm might impair the fertilization process. In a research setting, Sertraline may be used to selectively inhibit prostaglandin-induced Ca2+ influx.

Trial registration number

CRU326

Familial resemblance in markers of testicular function in fathers and their young sons: a cross-sectional study

STUDY QUESTION

Is testicular function associated within father-son pairs?

SUMMARY ANSWER

Familial resemblance in testis volume and serum markers of spermatogenesis was observed in father-son pairs.

WHAT IS KNOWN ALREADY

Studies suggest familial clustering of male subfertility and impaired spermatogenesis, but in men from the general population little is known about concordance in testicular function between fathers and sons.

STUDY DESIGN, SIZE, DURATION

This cross-sectional study with simultaneous collection of data in fathers and sons included 72 pairs (144 fathers and sons), unselected regarding testicular function were included.

PARTICIPANTS/MATERIALS, SETTING, METHODS

A subgroup of men from the background population and participating in a study on testicular function were asked permission to invite their fathers to participate in a similar setup. Fathers (median age of 53 years) and sons (median age of 19 years) participated in the same study setup including assessment of testis size, having a blood sample taken and analysed for serum levels of reproductive hormones (FSH, inhibin B, LH, testosterone, oestradiol, sex hormone-binding globulin (SHBG) and calculated free testosterone) and delivering a semen sample for assessment of traditional semen parameters. Mixed-effects models were fitted to estimate the familial resemblance as the proportion of variance in markers of testicular function due to shared factors for fathers and sons accounted for using random-effects. Variance components were calculated from both unadjusted and adjusted models.

MAIN RESULTS AND THE ROLE OF CHANCE

After adjustments, variance component analyses showed that familial resemblance between fathers and sons accounted for 48% (P < 0.001) of the variation in testicular volume, 32% (P = 0.009) of the variation in FSH, 31% (P = 0.009) of the variation in the inhibin B/FSH ratio, 33% (P = 0.007) and 45% (P < 0.001) of the variation in testosterone and free testosterone, respectively, and 31% (P = 0.009) of the variation in SHBG. None of the semen parameters were associated within father-son pairs.

LIMITATIONS, REASONS FOR CAUTION

The present study may have lacked power to detect associations for semen quality, as large intra- and inter-individual variation occur in semen parameters.

WIDER IMPLICATIONS OF THE FINDINGS

In this study, testis volume, serum testosterone and serum markers of spermatogenesis including FSH were associated in fathers and sons, suggesting an impact of paternal genetics for testicular function in the son. However, the estimated familial resemblance for spermatogenesis markers highlights that other factors, such as maternal genetics and prenatal as well as adult exposures, are also of major importance for testicular function.

STUDY FUNDING/COMPETING INTEREST(S)

The study has received funding from Danish Health Authority, Research Fund of the Capital Region of Denmark and Independent Research Fund Denmark (8020-00218B). None of the funders had any role in the study design, collection, analysis or interpretation of data, writing of the paper of publication decisions. The authors have nothing to disclose.

TRIAL REGISTRATION NUMBER

N/A.

Use of e-cigarettes associated with lower sperm counts in a cross-sectional study of young men from the general population

STUDY QUESTION

Are use of e-cigarettes and snuff associated with testicular function as previously shown for conventional cigarettes and marijuana?

SUMMARY ANSWER

Use of e-cigarettes is associated with reduced semen quality but not with higher serum testosterone level as observed for conventional cigarette use. Snuff use was not associated with markers of testicular function.

WHAT IS KNOWN ALREADY

Cigarette smoking has previously been associated with higher testosterone levels and impaired semen quality, whereas it is unresolved whether use of e-cigarettes or snuff influence the testicular function.

STUDY DESIGN, SIZE, DURATION

This cross-sectional population-based study included 2008 men with information on cigarette and marijuana use (enrolled between 2012 and 2018), among whom 1221 men also had information on e-cigarette and snuff use (enrolled between 2015 and 2018).

PARTICIPANTS/MATERIALS, SETTING, METHODS

Men (median age 19.0 years) from the general population provided a semen and blood sample and filled out a questionnaire on lifestyle including information on smoking behaviour. Associations between different types of smoking (e-cigarettes, snuff, marijuana and cigarettes) and reproductive hormones (total and free testosterone, sex hormone-binding globulin, LH, oestradiol and ratios of inhibin B/FSH, testosterone/LH and free testosterone/LH) and semen parameters (total sperm count and sperm concentration) were examined using multiple linear regression analyses adjusted for relevant confounders.

MAIN RESULTS AND THE ROLE OF CHANCE

Approximately half of the men (52%) were cigarette smokers, 13% used e-cigarettes, 25% used snuff and 33% used marijuana. Users of e-cigarettes and marijuana were often also cigarette smokers. Compared to non-users, daily e-cigarette users had significantly lower total sperm count (147 million vs 91 million) as did daily cigarette smokers (139 million vs 103 million), in adjusted analyses. Furthermore, significantly higher total and free testosterone levels were seen in cigarette smoking men (6.2% and 4.1% higher total testosterone and 6.2% and 6.2% higher free testosterone in daily smokers and occasional smokers, respectively, compared to non-smoking men), but not among e-cigarette users. Daily users of marijuana had 8.3% higher total testosterone levels compared to non-users. No associations were observed for snuff in relation to markers of testicular function.

LIMITATIONS, REASONS FOR CAUTION

We cannot exclude that our results can be influenced by residual confounding by behavioural factors not adjusted for. The number of daily e-cigarette users was limited and findings should be replicated in other studies.

WIDER IMPLICATIONS OF THE FINDINGS

This is the first human study to indicate that not only cigarette smoking but also use of e-cigarettes is associated with lower sperm counts. This could be important knowledge for men trying to achieve a pregnancy, as e-cigarettes are often considered to be less harmful than conventional cigarette smoking.

STUDY FUNDING/COMPETING INTEREST(S)

Funding was received from the Danish Ministry of Health (1-1010-308/59), the Independent Research Fund Denmark (8020-00218B), ReproUnion (20200407) and the Research Fund of the Capital Region of Denmark (A6176). The authors have nothing to disclose.

TRIAL REGISTRATION NUMBER

NA.

Paternal prescription medication before conception: A retrospective cohort study of all births in Denmark 1997-2017

AIM

To study what medication fathers are being prescribed in the months preceding conception.

METHODS

A retrospective cohort study of Danish national registries, comprising all births in Denmark 1997-2017 (1.3 million births). Time trends and absolute levels of paternal prescription medication in the 6 months prior to conception were assessed. While all medications were examined (N = 1335), we focused on the main medication groups, medications that have increased in use over time, and medications for which previous evidence exists of an effect on sperm quality.

RESULTS

The average number of prescriptions increased over the study period (from 0.75 prescriptions to 0.82 per birth). Polypharmacy (three or more prescriptions) increased from less than 8% to 10% of fathers. The use of pain medication, proton-pump inhibitors, selective serotonin reuptake inhibitors and some inhalants have all increased markedly over the last 20 years.

CONCLUSIONS

Potential harm to the offspring done by paternal medication may present an increasing problem. As paternal medication exposure is increasing, examination of generational effects, such as major birth defects, is necessary.

Influence of FGF23 and Klotho on male reproduction: Systemic vs direct effects

Currently, no treatment exists to improve semen quality in most infertile men. Here, we demonstrate systemic and direct effects of Fibroblast growth factor 23 (FGF23) and Klotho, which normally regulate vitamin D and mineral homeostasis, on testicular function. Direct effects are plausible because KLOTHO is expressed in both germ cells and spermatozoa and forms with FGFR1 a specific receptor for the bone-derived hormone FGF23. Treatment with FGF23 increased testicular weight in wild-type mice, while mice with global loss of either FGF23 or Klotho had low testicular weight, reduced sperm count, and sperm motility. Mice with germ cell-specific Klotho (gcKL) deficiency neither had a change in sperm count nor sperm motility. However, a tendency toward fewer pregnancies was detected, and significantly fewer Klotho heterozygous pups originated from gcKL knockdown mice than would be expected by mendelian inheritance. Moreover, gcKL mice had a molecular phenotype with higher testicular expression of Slc34a2 and Trpv5 than wild-type littermates, which suggests a regulatory role for testicular phosphate and calcium homeostasis. KLOTHO and FGFR1 were also expressed in human germ cells and spermatozoa, and FGF23 treatment augmented the calcium response to progesterone in human spermatozoa. Moreover, cross-sectional data revealed that infertile men with the highest serum Klotho levels had significantly higher serum Inhibin B and total sperm count than men with the lowest serum Klotho concentrations. In conclusion, this translational study suggests that FGF23 and Klotho influence gonadal function and testicular mineral ion homeostasis both directly and indirectly through systemic changes in vitamin D and mineral homeostasis.

Impact of psychological stress measured in three different scales on testis function: A cross-sectional study of 1362 young men

BACKGROUND

Studies have reported associations between psychological stress and semen quality, but most have been performed on selected populations using different stress measures. Thus, it is uncertain which stress scale best quantifies the effects of stress on testicular function.

OBJECTIVE

To study the association between three different measures of stress and testicular function in young men.

MATERIAL AND METHODS

In total, 1362 men (median age 19 years) delivered semen and blood samples. They also answered a questionnaire including information from three stress scales: Stress Symptoms, Stressful Life Events and Perceived Stress. Various statistical analyses for associations between stress and testicular function (semen quality and reproductive hormones) were performed.

RESULTS

Perceived Stress was negatively associated with sperm concentration, total count and motility and positively associated with serum FSH. Men with the highest scores (>30 points) had 38% (95% CI 3-84%) lower sperm concentration, 42% (95% CI 5-91%) lower total count and 22% (95% CI 2-32%) lower proportion of motile spermatozoa than men with the lowest scores (0-10 points). For the stress symptoms score, men with highest scores (>95th percentile vs. lower) had lower sperm concentration, total sperm count, motility and serum Inhibin-B/FSH-ratio. Although men with highest stress levels were characterized by an unhealthier lifestyle, adjusting for lifestyle factors did not attenuate results suggesting that the associations between stress and testicular function were not mediated by lifestyle. Stressful Life Events were not associated with testicular function.

DISCUSSION AND CONCLUSION

The linear association between Perceived Stress and semen parameters and lack of dose-response association for the other two stress scales indicated that perceived stress was the most sensitive marker of stress affecting semen quality in young men. The lack of associations between Stressful Life Events and testis function confirmed that the perception of stressful events rather than the stressful event per se matters.

Average sperm count remains unchanged despite reduction in maternal smoking: results from a large cross-sectional study with annual investigations over 21 years

STUDY QUESTION

How are temporal trends in lifestyle factors, including exposure to maternal smoking in utero, associated to semen quality in young men from the general population?

SUMMARY ANSWER

Exposure to maternal smoking was associated with lower sperm counts but no overall increase in sperm counts was observed during the study period despite a decrease in this exposure.

WHAT IS KNOWN ALREADY

Meta-analyses suggest a continuous decline in semen quality but few studies have investigated temporal trends in unselected populations recruited and analysed with the same protocol over a long period and none have studied simultaneous trends in lifestyle factors.

STUDY DESIGN, SIZE, DURATION

Cross-sectional population-based study including ~300 participants per year (total number = 6386) between 1996 and 2016.

PARTICIPANTS/MATERIALS, SETTING, METHODS

The study is based on men from the Greater Copenhagen area, Denmark, with a median age of 19 years, and unselected with regard to fertility status and semen quality. The men delivered a semen sample, had a blood sample drawn and a physical examination performed and answered a comprehensive questionnaire, including information on lifestyle and the mother's pregnancy. Temporal trends in semen quality and lifestyle were illustrated graphically, and trends in semen parameters and the impact of prenatal and current lifestyle factors were explored in multiple regression analyses.

MAIN RESULTS AND THE ROLE OF CHANCE

Throughout the study period, 35% of the men had low semen quality. Overall, there were no persistent temporal trends in semen quality, testicular volume or levels of follicle-stimulating hormone over the 21 years studied. The men's alcohol intake was lowest between 2011 and 2016, whereas BMI, use of medication and smoking showed no clear temporal trends. Parental age increased, and exposure in utero to maternal smoking declined from 40% among men investigated in 1996-2000 to 18% among men investigated in 2011-2016. Exposure to maternal smoking was associated with lower sperm counts but no overall increase in sperm counts was observed despite the decrease in this exposure.

LIMITATIONS, REASONS FOR CAUTION

Information of current and prenatal lifestyle was obtained by self-report, and the men delivered only one semen sample each.

WIDER IMPLICATIONS OF THE FINDINGS

The significant decline in in utero exposure to maternal smoking, which was not reflected in an overall improvement of semen quality at the population level, suggest that other unknown adverse factors may maintain the low semen quality among Danish men.

STUDY FUNDING/COMPETING INTEREST(S)

The study has received financial support from the ReproUnion; the Research fund of Rigshospitalet, Copenhagen University Hospital; the European Union (Contract numbers BMH4-CT96-0314,QLK4-CT-1999-01422, QLK4-CT-2002-00603, FP7/2007-2013, DEER Grant agreement no. 212844); the Danish Ministry of Health; the Danish Environmental Protection Agency; A.P. Møller and wife Chastine McKinney Møllers foundation; and Svend Andersens Foundation. None of the funders had any role in the study design, collection, analysis or interpretation of data, writing of the paper or publication decisions.

TRIAL REGISTRATION NUMBER

N/A.

Anogenital distance is associated with semen quality but not reproductive hormones in 1106 young men from the general population

STUDY QUESTION

Is anogenital distance (AGD) associated with semen quality and reproductive hormones in men from the general population?

SUMMARY ANSWER

Short AGD measured from the anus to the base of scrotum (AGDAS) was associated with reduced sperm counts and morphology but not with sperm motility or reproductive hormones.

WHAT IS KNOWN ALREADY

AGD is longer in males than in females. In rodents, AGD is a well-established and sensitive marker of disruption during the masculinization programming window in utero and it has been suggested to be so in humans as well. Therefore, the average AGD would be expected to be shorter in men with poor semen quality, which some studies have confirmed while others have not.

STUDY DESIGN, SIZE, DURATION

This cross-sectional population-based study was of 1106 men included between 2012 and 2016.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Men from the general Danish population (median age 19 years), unselected with regard to fertility status and semen quality, delivered a semen sample, had a blood sample drawn, which was analyzed for concentrations of reproductive hormones, and answered a comprehensive questionnaire. They also had a physical examination performed including determination of AGD measured as the distance between anus and scrotum (AGDAS) and penis (AGDAP). Odds ratios (OR) and 95% CI were estimated for a man having abnormal semen parameters according to the World Health Organization's reference values or a low/high concentration of reproductive hormones (defined as the lowest or highest 10%) depending on AGD. AGD was categorized in four strata: ≤10th percentile, 10th-30th percentile, 30th-50th percentile and >50th percentile.

MAIN RESULTS AND THE ROLE OF CHANCE

Men with the 10% shortest AGDAS had a more than doubled risk (OR: 2.19, 95% CI: 1.40-3.42) of being in the subfertile range for either sperm concentration (<15 million/mL) or sperm morphology (<4%) compared to men with AGDAS above the median (reference). Men in the 10th-30th percentile also had an increased OR of 1.48 (95% CI: 1.06-2.08) but not men in the 30th-50th percentile (OR: 1.14, 95% CI: 0.81-1.62). AGDAP was only weakly related to semen quality. AGD was not associated with testicular volume or any of the reproductive hormones.

LIMITATIONS, REASONS FOR CAUTION

Limitations include the potential non-differential misclassification of reproductive outcomes based on a single semen and blood sample and some between-examiner differences in AGD measurements which introduces noise and may result in an underestimation of observed associations.

WIDER IMPLICATIONS OF THE FINDINGS

Our study of men from the general population confirmed associations between AGD and semen quality, supporting the hypothesis that AGD in humans could be a marker of fetal testicular development. This suggests that the low semen quality in Danish men may partly be explained by prenatal factors.

STUDY FUNDING/COMPETING INTEREST(S)

The study has received financial support from the ReproUnion (L.P.); the Research fund of Rigshospitalet, Copenhagen University Hospital (N.J.); Grants R01ES016863-04 and R01ES016863-02S4; National Institute of Environmental Health Sciences (NIEHS) and National Institute of Environmental Health Sciences grant (P30ES023515) (S.S.); the European Union (Contract numbers BMH4-CT96-0314, QLK4-CT-1999-01422, QLK4-CT-2002-00603, FP7/2007-2013, DEER Grant agreement no. 212844); the Danish Ministry of Health; the Danish Environmental Protection Agency; A.P. Møller and wife Chastine McKinney Møllers foundation; and Svend Andersens Foundation. None of the funders had any role in the study design, collection, analysis or interpretation of data, writing of the paper or publication decisions. The authors have nothing to declare.

TRIAL REGISTRATION NUMBER

N/A.

An update on semen quality among young Finnish men and comparison with Danish data

Background

Finnish men used to have higher semen quality than Danish men. However, recent studies showed that semen quality in Finland has declined, but it has been relatively stable in Denmark.

Objective

This study aimed to compare new data on semen quality of the young Finnish men to that of Danish men.

Materials and methods

In this cross‐sectional study, 18‐ to 19‐year‐old men residing in Turku, Finland and Copenhagen, Denmark, were invited to participate in 2008–2011. Each man filled in a questionnaire, provided one semen sample and underwent andrological examination. Semen samples were analyzed according to WHO. Multiway ANOVA was used to adjust semen variables for duration of sexual abstinence and age (and time from ejaculation to the start of semen analysis for sperm motility).

Results

Altogether 287 Finnish men and 873 Danish men participated in the study. The adjusted median sperm concentrations were 49 and 47 million/mL for Finnish and Danish men, respectively (p = 0.48). The adjusted median total sperm counts were 148 million in Finland and 146 million in Denmark (p = 0.87). The adjusted median percentages of morphologically normal spermatozoa were 6.9% in Finland and 6.5% in Denmark, p = 0.27. Finnish men had higher adjusted median percentages of motile spermatozoa (A+B+C) than Danish men (80% vs. 69%, p < 0.001). The proportion of men who had low semen quality (sperm concentration, percentage of morphologically normal spermatozoa or percentage of progressively motile spermatozoa below WHO reference limits) was lower in Finland (25.4%) than in Denmark (34.6%), p = 0.004.

Discussion

Considerable percentage of men in both countries had low semen quality. The deteriorating semen quality in Finland may result in decreasing fecundity, which is a cause of concern.

Conclusion

The formerly high semen quality in Finland has converged to the lower Danish levels. Our findings demonstrate the importance of continuing surveillance of semen quality.

Quantification of the Leydig cell compartment in testicular biopsies and association with biochemical Leydig cell dysfunction in testicular cancer survivors

A simple histological method to evaluate the Leydig cell compartment is lacking. We aimed to establish such a method and to investigate if Leydig cell hyperplasia of the biopsy contralateral to the tumour-bearing testicle in patients with testicular germ cell cancer is associated with biochemical signs of Leydig cell dysfunction after long-term follow-up. A case group of 50 long-term testicular germ cell cancer survivors without human chorionic gonadotropin elevation, 10 testicular germ cell cancer patients with elevated human chorionic gonadotropin and 10 controls without testicular malignancy were included. For each subject, 2-4 representative sections from their testicular biopsies were selected for analysis. Using the image processing program ImageJ (V.1.48, NIH), an area with a minimum of 50 tubules was selected and delineated (total selected area) and the total Leydig cell area was calculated by adding up every delineated Leydig cell group within the total selected area. Four different methods were tested for the ability to quantify the Leydig cell compartment. In the 50 testicular germ cell cancer survivors, associations between the area of the Leydig cell compartment and serum levels of testosterone and luteinising hormone were investigated using linear regression analysis. The Leydig cell compartment was best quantified by the total Leydig cell area/total selected area index, which was significantly larger in the human chorionic gonadotropin-positive patients than in controls (P = 0.00001). In the 50 human chorionic gonadotropin-negative testicular germ cell cancer survivors, increasing total Leydig cell area/total selected area was significantly associated with decreased levels of total testosterone and decreased total testosterone/luteinising hormone ratio after a median of 9-year follow-up. In conclusion, a new simple method, total Leydig cell area/total selected area, was established to estimate the Leydig cell compartment in testicular biopsies. The index identified Leydig cell hyperplasia in the contralateral biopsy in patients with testicular germ cell cancer, and it was associated with long-term biochemical Leydig cell dysfunction. Although in testicular germ cell cancer survivors, the clinical value is limited because the contralateral biopsies are not commonly available, we propose a closer andrological follow-up in any patient with an increased total Leydig cell area/total selected area index.

Maternal exposure to UV filters: associations with maternal thyroid hormones, IGF-I/IGFBP3 and birth outcomes

BACKGROUND

Several chemical UV filters/absorbers ('UV filters' hereafter) have endocrine-disrupting properties in vitro and in vivo. Exposure to these chemicals, especially during prenatal development, is of concern.

OBJECTIVES

To examine maternal exposure to UV filters, associations with maternal thyroid hormone, with growth factor concentrations as well as to birth outcomes.

METHODS

Prospective study of 183 pregnant women with 2nd trimester serum and urine samples available. Maternal concentrations of the chemical UV filters benzophenone-1 (BP-1) and benzophenone-3 (BP-3) in urine and 4-hydroxy-benzophenone (4-HBP) in serum were measured by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The relationships between 2nd trimester maternal concentrations of the three chemical UV filters and maternal serum concentrations of thyroid hormones and growth factors, as well as birth outcomes (weight, height, and head and abdominal circumferences) were examined.

RESULTS

Positive associations between maternal serum concentrations of 4-HBP and triiodothyronine (T₃), thyroxine (T₄), insulin-like growth factor I (IGF-I) and its binding protein IGFBP3 were observed in mothers carrying male fetuses. Male infants of mothers in the middle 4-HBP exposure group had statistically significantly lower weight and shorter head and abdominal circumferences at birth compared to the low exposure group.

CONCLUSIONS

Widespread exposure of pregnant women to chemical UV filters and the possible impact on maternal thyroid hormones and growth factors, and on fetal growth, calls for further studies on possible long-term consequences of the exposure to UV filters on fetal development and children's health.

Presence of benzophenones commonly used as UV filters and absorbers in paired maternal and fetal samples

BACKGROUND

Previous studies have demonstrated widespread exposure of humans to certain benzophenones commonly used as UV filters or UV absorbers; some of which have been demonstrated to have endocrine disrupting abilities.

OBJECTIVES

To examine whether benzophenones present in pregnant women pass through the placental barrier to amniotic fluid and further to the fetal blood circulation.

METHODS

A prospective study of 200 pregnant women with simultaneously collected paired samples of amniotic fluid and maternal serum and urine. In addition, unique samples of human fetal blood (n=4) obtained during cordocentesis: and cord blood (n=23) obtained at delivery, both with paired maternal samples of serum and urine collected simultaneously, were used. All biological samples were analyzed by TurboFlow-liquid chromatography - tandem mass spectrometry for seven different benzophenones.

RESULTS

Benzophenone-1 (BP-1), benzophenone-3 (BP-3), 4-methyl-benzophenone (4-MBP), and 4-hydroxy-benzophenone (4-HBP) were all detectable in amniotic fluid and cord blood samples and except 4-HBP also in fetal blood; albeit at a low frequency. BP-1 and BP-3 were measured at ~10-times lower concentrations in fetal and cord blood compared to maternal serum and 1000-times lower concentration compared to maternal urine levels. Therefore BP-1 and BP-3 were only detectable in the fetal circulation in cases of high maternal exposure indicating some protection by the placental barrier. 4-MBP seems to pass into fetal and cord blood more freely with a median 1:3 ratio between cord blood and maternal serum levels. Only for BP-3, which the women seemed to be most exposed to, did the measured concentrations in maternal urine and serum correlate to concentrations measured in amniotic fluid. Thus, for BP-3, but not for the other tested benzophenones, maternal urinary levels seem to be a valid proxy for fetal exposure.

CONCLUSIONS

Detectable levels of several of the investigated benzophenones in human amniotic fluid as well as in fetal and cord blood calls for further investigations of the toxicokinetic and potential endocrine disrupting properties of these compounds in order for better assessment of the risk to the developing fetus.

Assumed non-persistent environmental chemicals in human adipose tissue; matrix stability and correlation with levels measured in urine and serum

The aim of this study was to (1) optimize a method for the measurement of parabens and phenols in adipose tissue, (2) evaluate the stability of chemical residues in adipose tissue samples, and (3) study correlations of these compounds in urine, serum, and adipose tissue. Samples were obtained from adults undergoing trauma surgery. Nine phenols and seven parabens were determined by isotope diluted TurboFlow-LC-MS/MS. The analytical method showed good accuracy and precision. Limits of detection (LOD) for parabens and phenols ranged from 0.05 to 1.83ng/g tissue. Good recovery rates were found, even when biological samples remained defrosted up to 24h. Benzophenone-3 (BP-3; range of values: <LOD-1.48ng/g tissue) and methylparaben (MeP; <LOD-1.78ng/g tissue) were detected in >70% of adipose tissue samples, while bisphenol-A (BPA; <LOD-3.28ng/g tissue) and 2-phenylphenol (2-PP; <LOD-0.78ng/g tissue) were detected in >40% of adipose tissue samples. In general, levels were similar between adipose tissue and serum, while a correlation between adipose tissue and urine was only found for BP-3. In conclusion, adipose tissue samples in this study were found to contain environmental chemicals considered to be non-persistent, whose levels were weakly or not at all correlated with the urine burden. Therefore, adipose tissue may potentially provide additional information to that obtained from other biological matrices. Further investigations are warranted to explore whether adipose tissue might be a suitable matrix for assessment of the consequences for human health of mid/long-term exposure to these chemicals.

Clinical, genetic, biochemical, and testicular biopsy findings among 1,213 men evaluated for infertility

OBJECTIVE

To study the pathologic findings among men evaluated for infertility.

DESIGN

A retrospective, single-center, cross-sectional study.

SETTING

University hospital-based research center.

PARTICIPANT(S)

We included data from 1,213 medical records from infertile men referred for diagnostic work-up from 2005 to 2009.

INTERVENTIONS(S)

None.

MAIN OUTCOME MEASURE(S)

Health history, clinical findings, chromosome/genetic aberrations, semen quality, reproductive hormones.

RESULT(S)

In total, 64.4% of the infertile men had one or more reproductive disorders or factors influencing fertility, leaving 35.6% diagnosed as idiopathic infertile. In 244 patients (20%), including seven cases of testicular cancer and/or germ cell neoplasia in situ, a pathologic finding was first detected during diagnostic work-up. Two hundred four patients (16.8%) had a history of cryptorchidism and 154 (12.7%) of varicocele (grade 2 and 3). Thirty-three patients had chromosomal abnormalities, including 16 with sex chromosome abnormalities (11 with 47,XXY). Y-chromosome microdeletions were detected in 65 patients (5.4%). One hundred thirty-three had azoospermia, of which 58 had testicular biopsy findings (Sertoli cell-only syndrome: n = 23; spermatogenic arrest: n = 7; impaired spermatogenesis and atrophy: n = 28). Additionally, in idiopathic infertile men and infertile men with additional symptoms of testicular dysgenesis syndrome, 22.5% presented with a degree of Leydig cell insufficiency, with the highest frequency (33.1%) among patients with sperm concentration <5 million/mL.

CONCLUSION(S)

We report pathologic findings that could explain the male-factor infertility in two-thirds of infertile men referred to our center. Thus, male infertility may be a sign of an underlying disease that warrants attention.

Prenatal pesticide exposure and PON1 genotype associated with adolescent body fat distribution evaluated by dual X-ray absorptiometry (DXA)

Many modern pesticides have endocrine disrupting abilities and early-life exposure may affect growth and disease risk later in life. Previously, we reported associations between prenatal pesticide exposure and higher childhood body fat content measured by anthropometry. The associations were affected by child PON1 Q192R genotype. We aimed to study whether prenatal pesticide exposure was still associated with body fat content and distribution in the children at puberty and the potential impact of both maternal and child PON1 Q192R genotype. In this prospective cohort study of 247 children born by occupationally exposed or unexposed women (greenhouse workers and controls) two follow-up examinations (age 10-15 and 11-16 years) including simple anthropometry, skinfold measurements, pubertal staging and blood sampling were performed. Total and regional fat% was determined by dual X-ray absorptiometry (DXA) at age 10-15. Prenatal pesticide exposure was associated with increased total, android, and gynoid fat percentage (DXA) at age 10-15 years after adjustment for sex, socioeconomic status, and puberty (all β = 0.5 standard deviation score (SDS) p < 0.05). Stratified by sex, the associations were significant in girls (total fat: β = 0.7 SDS, android-gynoid ratio: β = 0.1, both p < 0.05), but not in boys. Carrying the R-allele (child or mother, separately, or both) augmented the differences between exposed and unexposed children (total fat: β = 1.0 SDS, β = 0.8 SDS, p < 0.05, respectively, and β = 1.2 SDS, p < 0.01). No exposure-related differences were found if either the child or mother had the QQ wild-type. At age 11-16, exposed children tended to have a higher total fat% estimated by skinfolds than unexposed children (p = 0.06). No significant associations between prenatal exposure and body mass index or waist circumference were found. Prenatal pesticide exposure was associated with higher adolescent body fat content, including android fat deposition, independent of puberty. Girls appeared more susceptible than boys. Furthermore, the association depended on maternal and child PON1 Q192R genotype.

Burden of disease and costs of exposure to endocrine disrupting chemicals in the European Union: an updated analysis

A previous report documented that endocrine disrupting chemicals contribute substantially to certain forms of disease and disability. In the present analysis, our main objective was to update a range of health and economic costs that can be reasonably attributed to endocrine disrupting chemical exposures in the European Union, leveraging new burden and disease cost estimates of female reproductive conditions from accompanying report. Expert panels evaluated the epidemiologic evidence, using adapted criteria from the WHO Grading of Recommendations Assessment, Development and Evaluation Working Group, and evaluated laboratory and animal evidence of endocrine disruption using definitions recently promulgated by the Danish Environmental Protection Agency. The Delphi method was used to make decisions on the strength of the data. Expert panels consensus was achieved for probable (>20%) endocrine disrupting chemical causation for IQ loss and associated intellectual disability; autism; attention deficit hyperactivity disorder; endometriosis; fibroids; childhood obesity; adult obesity; adult diabetes; cryptorchidism; male infertility, and mortality associated with reduced testosterone. Accounting for probability of causation, and using the midpoint of each range for probability of causation, Monte Carlo simulations produced a median annual cost of €163 billion (1.28% of EU Gross Domestic Product) across 1000 simulations. We conclude that endocrine disrupting chemical exposures in the EU are likely to contribute substantially to disease and dysfunction across the life course with costs in the hundreds of billions of Euros per year. These estimates represent only those endocrine disrupting chemicals with the highest probability of causation; a broader analysis would have produced greater estimates of burden of disease and costs.

Temporal Trends in Fertility Rates: A Nationwide Registry Based Study from 1901 to 2014

Objective

Increasing age at first childbirth has been suggested to increase the risk for infertility. Our objective is to determine whether women above thirty years of age historically have been able to sustain fertility rates above replacement level.

Design

A descriptive nationwide Danish study using birth registries from 1901–2014.

Setting

Information on women’s age at childbirth was obtained by using records from primary, secondary and tertiary institutions.

Participants

Mothers to 8,024,969 live births.

Main outcome measures

Mothers were stratified according to age at childbirth to determine total and age specific fertility rates.

Results

Total fertility rate (TFR) decreased from 4.1 to 1.8 children per woman and age specific fertility also decreased from 1901 to 2014. Women aged 30–34, 35–39 or 40–44 years in the first decade of the 20th century had higher fertility rates than the corresponding five year younger age groups (25–29, 30–34 and 35–39, respectively) have had for the last 65 years. On average, women gave birth to two children after the age of 30 and one or more child after 35 years of age in the beginning of the 1900s. Furthermore, women more than 40 years of age accounted for 10% of TFR in 1901 compared with 4% in 2014 despite usage of assisted reproduction.

Conclusion

This nationwide study shows that women above 30 years of age historically have been able to sustain fertility rates above replacement level. This implies that other factors besides age are strong determinants of fertility in women above 30 years of age.

Testicular function in a birth cohort of young men

STUDY QUESTION

By investigating a birth cohort with a high ongoing participation rate to derive an unbiased population, what are the parameters and influences upon testicular function for a population not selected with regard to fertility?

SUMMARY ANSWER

While varicocele, cryptorchidism and obesity may impact on human testicular function, most common drug exposures and the presence of epididymal cysts appear to have no or minimal adverse impact.

WHAT IS KNOWN ALREADY

The majority of previous attempts to develop valid reference populations for spermatogenesis have relied on potentially biased sources such as recruits from infertility clinics, self-selected volunteer sperm donors for research or artificial insemination or once-fertile men seeking vasectomy. It is well known that studies requiring semen analysis have low recruitment rates which consequently question their validity. However, there has been some concern that a surprisingly high proportion of young men may have semen variables that do not meet all the WHO reference range criteria for fertile men, with some studies reporting that up to one half of participants have not meet the reference range for fertile men. Reported median sperm concentrations have ranged from 40 to 60 million sperm/ml.

STUDY DESIGN, SIZE AND DURATION

The Western Australian Pregnancy Cohort (Raine) was established in 1989. At 20-22 years of age, members of the cohort were contacted to attend for a general follow-up, with 753 participating out of the 913 contactable men. Of these, 423 men (56% of participants in the 20-22 years cohort study, 46% of contactable men) participated in a testicular function study. Of the 423 men, 404 had a testicular ultrasound, 365 provided at least one semen sample, 287 provided a second semen sample and 384 provided a blood sample.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Testicular ultrasound examinations were performed at King Edward Memorial Hospital, Subiaco, Perth, for testicular volume and presence of epididymal cysts and varicoceles. Semen samples were provided and analysed by standard semen assessment and a sperm chromatin structural assay (SCSA) at Fertility Specialists of Western Australia, Claremont, Perth. Serum blood samples were provided at the University of Western Australia, Crawley, Perth and were analysed for serum luteinizing hormone (LH), follicular stimulating hormone (FSH), inhibin B, testosterone, dihydrotestosterone (DHT), dehydroepiandrosterone (DHEA), estradiol, estrone and the primary metabolites of DHT: 5α-androstane-3α,17β-diol (3α-diol) and 5-α androstane-3-β-17-beta-diol (3β-diol). Serum steroids were measured by liquid chromatography, mass spectrometry and LH, FSH and inhibin B were measured by ELISA assays.

MAIN RESULTS AND THE ROLE OF CHANCE

Cryptorchidism was associated with a significant reduction in testicular (P = 0.047) and semen (P = 0.027) volume, sperm concentration (P = 0.007) and sperm output (P = 0.003). Varicocele was associated with smaller testis volume (P < 0.001), lower sperm concentration (P = 0.012) and total sperm output (P = 0.030) and lower serum inhibin B levels (P = 0.046). Smoking, alcohol intake, herniorrhaphy, an epididymal cyst, medication and illicit drugs were not associated with any significant semen variables, testicular volume or circulating reproductive hormones. BMI had a significantly negative correlation with semen volume (r = -0.12, P = 0.048), sperm output (r = -0.13, P = 0.02), serum LH (r = -0.16, P = 0.002), inhibin B (r = -0.16, P < 0.001), testosterone (r = -0.23, P < 0.001) and DHT (r = -0.22, P < 0.001) and a positive correlation with 3αD (r = 0.13, P = 0.041) and DHEA (r = 0.11, P = 0.03). Second semen samples compared with the first semen samples in the 287 participants who provided two samples, with no significant bias by Bland-Altman analysis. Testis volume was significantly correlated positively with sperm concentration (r = 0.25, P < 0.001) and sperm output (r = 0.29, P < 0.001) and inhibin B (r = 0.42, P < 0.001), and negatively correlated with serum LH (r = -0.24, P < 0.001) and FSH (r = -0.32, P < 0.001). SCSA was inversely correlated with sperm motility (r = -0.20, P < 0.001) and morphology (r = -0.16, P = 0.005). WHO semen reference criteria were all met by only 52 men (14.4%). Some criteria were not met at first analysis in 15-20% of men, including semen volume (<1.5 ml, 14.8%), total sperm output (<39 million, 18.9%), sperm concentration (<15 million/ml, 17.5%), progressive motility (<32%, 14.4%) and morphologically normal sperm (<4%, 26.4%), while all five WHO criteria were not met in four participants (1.1%).

LIMITATIONS AND REASONS FOR CAUTION

This was a large cohort study; however, potential for recruitment bias still exists. Men who did not participate in the testicular evaluation study (n = 282) did not differ from those who did (n = 423) with regard to age, weight, BMI, smoking or circulating reproductive hormones (LH, FSH, inhibin B, T, DHT, E2, E1, DHEA, 3α-diol, 3β-diol), but were significantly shorter (178 versus 180 cm, P = 0.008) and had lower alcohol consumption (P = 0.019) than those who did participate.

WIDER IMPLICATIONS OF THE FINDINGS

This study demonstrated the feasibility of establishing a birth cohort to provide a relatively unbiased insight into population-representative sperm output and function and of investigating its determinants from common exposures. While varicocele, cryptorchidism and obesity may impact on human testicular function, most common drug exposures and the presence of epididymal cysts appear to have little adverse impact, and this study suggests that discrepancies from the WHO reference ranges are expected, due to its derivation from non-population-representative fertile populations.

Urinary phthalates from 168 girls and boys measured twice a year during a 5-year period: associations with adrenal androgen levels and puberty

BACKGROUND

Little is known about the possible deleterious effects of phthalate exposure on endogenous sex steroid levels in children.

OBJECTIVE

Our objective was to investigate whether urinary phthalate metabolite levels are associated with circulating adrenal androgen levels and age at puberty.

METHODS

This was a longitudinal study of 168 healthy children (84 girls) examined every 6 months for 5 years. Serum levels of dehydroepiandrostenedione sulfate (DHEAS), Δ4-androstenedione, testosterone, and urinary morning excretion of 14 phthalate metabolites, corresponding to 7 different phthalate diesters were determined. A variation in urinary excretion of phthalates was evident in each child, which made a mean of repetitive samples more representative for long-term excretion than a single determination.

RESULTS

We found that girls with excretion of monobutyl phthalate isomers (MBP) and di(2-ethylhexyl) phthalate metabolites above the geometric group mean (795 and 730 ng/kg, respectively) had lower levels of DHEAS and Δ4-androstenedione, although statistically significant only at 13 years of age. In boys, we found that excretion of monobenzyl phthalate above the geometric group mean (346 ng/kg) was associated with lower levels of DHEAS at 11 years of age but higher levels of testosterone at 13 years of age. The same trend was observed for MBP excretion, albeit not statistically significant. A lower age at pubarche was observed in boys with excretion of MBP above the geometric group mean (11.0 vs 12.3 years, P = 0.005).

CONCLUSION

Our data indicate that exposure to dibutyl phthalate isomers (DBP) (in girls) and butylbenzyl phthalate (in boys) are negatively associated with adrenal androgen levels and in boys positively associated with testosterone level at 13 years of age. High exposure to DBP was associated with earlier age at pubarche in boys. In girls, no associations between phthalate exposure and age at pubertal milestones were observed.

Science and policy on endocrine disrupters must not be mixed: a reply to a "common sense" intervention by toxicology journal editors

The "common sense" intervention by toxicology journal editors regarding proposed European Union endocrine disrupter regulations ignores scientific evidence and well-established principles of chemical risk assessment. In this commentary, endocrine disrupter experts express their concerns about a recently published, and is in our considered opinion inaccurate and factually incorrect, editorial that has appeared in several journals in toxicology. Some of the shortcomings of the editorial are discussed in detail. We call for a better founded scientific debate which may help to overcome a polarisation of views detrimental to reaching a consensus about scientific foundations for endocrine disrupter regulation in the EU.

A cohort effect on serum testosterone levels in Finnish men

OBJECTIVE

To investigate whether a population-level decline in serum testosterone exists in Finnish men. In comparison with other European populations, Finnish men have compared well in the studies of reproductive health (i.e. semen quality, incidence of cryptorchidism and testicular cancer); thus, we expected no significant cohort-dependent decrease in serum testosterone.

METHODS

We analysed serum levels of testosterone, gonadotrophin and sex hormone binding globulin (SHBG) in 3271 men representing different ages (25-74 years) and birth cohorts within three large Finnish population surveys conducted in 1972, 1977 and 2002.

RESULTS

Serum testosterone levels decreased (from 25.3 nmol/l in 25- to 29-year-old men gradually to 16.9 nmol/l in 70- to 74-year-old men), whereas SHBG and gonadotrophin levels increased with increasing age. In addition, a significant secular trend in testosterone (total and free), SHBG and gonadotrophin levels was observed with lower levels in more recently born age-matched men. Serum testosterone level decreased in men aged 60-69 years from 21.9 nmol/l (men born 1913-1922) to 13.8 nmol/l (men born 1942-1951). These decreases remained significant following adjustment for BMI. An age-independent birth cohort effect existed on reproductive hormones measured in the Finnish men. In concert with the lower free testosterone levels, we observed lower gonadotrophin levels, suggesting that while there may be detrimental changes at the gonad level, the hypothalamus-pituitary-axis is not responding appropriately to this change.

CONCLUSIONS

The more recently born Finnish men have lower testosterone levels than their earlier born peers. This study offers no explanation for this substantial recent adverse development.

Sunscreens: are they beneficial for health? An overview of endocrine disrupting properties of UV-filters

Today, topical application of sunscreens, containing ultraviolet-filters (UV-filters), is preferred protection against adverse effects of ultraviolet radiation. Evidently, use of sunscreens is effective in prevention of sunburns in various models. However, evidence for their protective effects against melanoma skin cancer is less conclusive. Three important observations prompted us to review the animal data and human studies on possible side effects of selected chemical UV-filters in cosmetics. (1) the utilization of sunscreens with UV-filters is increasing worldwide; (2) the incidence of the malignant disorder for which sunscreens should protect, malignant melanoma, is rapidly increasing and (3) an increasing number of experimental studies indicating that several UV-filters might have endocrine disruptive effects. The selected UV-filters we review in this article are benzophenone-3 (BP-3), 3-benzylidene camphor (3-BC), 3-(4-methyl-benzylidene) camphor (4-MBC), 2-ethylhexyl 4-methoxy cinnamate (OMC), Homosalate (HMS), 2-ethylhexyl 4-dimethylaminobenzoate (OD-PABA) and 4-aminobenzoic acid (PABA). The potential adverse effects induced by UV-filters in experimental animals include reproductive/developmental toxicity and disturbance of hypothalamic-pituitary-thyroid axis (HPT). Few human studies have investigated potential side effects of UV-filters, although human exposure is high as UV-filters in sunscreens are rapidly absorbed from the skin. One of the UV-filters, BP-3, has been found in 96% of urine samples in the US and several UV-filters in 85% of Swiss breast milk samples. It seems pertinent to evaluate whether exposure to UV-filters contribute to possible adverse effects on the developing organs of foetuses and children.

Endocrine-disrupting chemicals and public health protection: a statement of principles from The Endocrine Society

An endocrine-disrupting chemical (EDC) is an exogenous chemical, or mixture of chemicals, that can interfere with any aspect of hormone action. The potential for deleterious effects of EDC must be considered relative to the regulation of hormone synthesis, secretion, and actions and the variability in regulation of these events across the life cycle. The developmental age at which EDC exposures occur is a critical consideration in understanding their effects. Because endocrine systems exhibit tissue-, cell-, and receptor-specific actions during the life cycle, EDC can produce complex, mosaic effects. This complexity causes difficulty when a static approach to toxicity through endocrine mechanisms driven by rigid guidelines is used to identify EDC and manage risk to human and wildlife populations. We propose that principles taken from fundamental endocrinology be employed to identify EDC and manage their risk to exposed populations. We emphasize the importance of developmental stage and, in particular, the realization that exposure to a presumptive "safe" dose of chemical may impact a life stage when there is normally no endogenous hormone exposure, thereby underscoring the potential for very low-dose EDC exposures to have potent and irreversible effects. Finally, with regard to the current program designed to detect putative EDC, namely, the Endocrine Disruptor Screening Program, we offer recommendations for strengthening this program through the incorporation of basic endocrine principles to promote further understanding of complex EDC effects, especially due to developmental exposures.

Association between chemical pattern in breast milk and congenital cryptorchidism: modelling of complex human exposures

During the past four decades, there has been an increase in the incidence rate of male reproductive disorders in some, but not all, Western countries. The observed increase in the prevalence of male reproductive disorders is suspected to be ascribable to environmental factors as the increase has been too rapid to be explained by genetics alone. To study the association between complex chemical exposures of humans and congenital cryptorchidism, the most common malformation of the male genitalia, we measured 121 environmental chemicals with suspected or known endocrine disrupting properties in 130 breast milk samples from Danish and Finnish mothers. Half the newborns were healthy controls, whereas the other half was boys with congenital cryptorchidism. The measured chemicals included polychlorinated biphenyls (PCBs), polybrominated diphenyl-ethers, dioxins (OCDD/PCDFs), phthalates, polybrominated biphenyls and organochlorine pesticides. Computational analysis of the data was performed using logistic regression and three multivariate machine learning classifiers. Furthermore, we performed systems biology analysis to explore the chemical influence on a molecular level. After correction for multiple testing, exposure to nine chemicals was significantly different between the cases and controls in the Danish cohort, but not in the Finnish cohort. The multivariate analysis indicated that Danish samples exhibited a stronger correlation between chemical exposure patterns in breast milk and cryptorchidism than Finnish samples. Moreover, PCBs were indicated as having a protective effect within the Danish cohort, which was supported by molecular data recovered through systems biology. Our results lend further support to the hypothesis that the mixture of environmental chemicals may contribute to observed adverse trends in male reproductive health.

Expression of the vitamin D metabolizing enzyme CYP24A1 at the annulus of human spermatozoa may serve as a novel marker of semen quality

Vitamin D (VD) is important for male reproduction in mammals and the VD receptor (VDR) and VD-metabolizing enzymes are expressed in human spermatozoa. The VD-inactivating enzyme CYP24A1 titrates the cellular responsiveness to VD, is transcriptionally regulated by VD, and has a distinct expression at the sperm annulus. Here, we investigated if CYP24A1 expression serves as a marker for VD metabolism in spermatozoa, and whether CYP24A1 expression was associated with semen quality. We included 130 men (53 healthy young volunteers and 77 subfertile men) for semen analysis and immunocytochemical (ICC) detection of CYP24A1. Another 40 men (22 young, 18 subfertile) were tested for in vitro effects of 1,25(OH)(2)D(3) on intracellular calcium concentration ([Ca(2+)](i)) and sperm motility. Double ICC staining showed that CYP24A1 and VDR were either concomitantly expressed or absent in 80% of the spermatozoa from young men. The median number of CYP24A1-expressing spermatozoa was 1% in subfertile men and thus significantly (p < 0.0005) lower than 25% in spermatozoa from young men. Moreover, CYP24A1 expression correlated positively with total sperm count, -concentration, -motility and -morphology (all p < 0.004), and the percentage of CYP24A1-positive spermatozoa increased (15 vs. 41%, p < 0.0005) after percoll-gradient-centrifugation. We noticed that the presence of >3% CYP24A1-positive spermatozoa distinguished young men from subfertile men with a sensitivity of 66.0%, a specificity of 77.9% and a positive predictive value of 98.3%. Functional studies revealed that 1,25(OH)(2)D(3) increased [Ca(2+)](i) and sperm motility in young healthy men, while 1,25(OH)(2)D(3) was unable to increase motility in subfertile patients. In conclusion, we suggest that CYP24A1 expression at the annulus may serve as a novel marker of semen quality and an objective proxy for sperm function.

Smaller genitals at school age in boys whose mothers were exposed to non-persistent pesticides in early pregnancy

Endocrine disrupting chemicals are believed to play a role in the development of the testicular dysgenesis syndrome. Many pesticides are known to have endocrine disrupting abilities. In a previous study, sons of women who were occupationally exposed to non-persistent pesticides in early pregnancy showed signs of impaired reproductive function (reduced genital size and altered serum hormone concentrations) at three months of age. To assess the possible long-term effects of prenatal pesticide exposure, the boys were re-examined at 6-11 years. The 94 boys (59 exposed, 35 unexposed) underwent genital examinations including ultrasound of testicular volumes, puberty staging (Tanner), anthropometry, and blood sampling. Only a few of the boys had reached puberty (n = 3). Among prepubescent boys, testicular volume and penile length (age- and weight-adjusted) were reduced if mothers were exposed to pesticides. The effects were associated with the maternal exposure levels, so that high-exposed boys had smaller genitals than medium-exposed boys, who had smaller genitals than those who were unexposed. Boys of mothers in the high exposure group (n = 23) had 24.7% smaller testes (95% CI: -62.2; -10.1) and 9.4% shorter penile length (95% CI: -16.8; -1.1) compared with the unexposed. The testicular volume and penile length at school age could be tracked to measures from the same boys made at 3 months, e.g. those that had small testes at school age also had small testes at 3 months. Pituitary and testicular hormone serum concentrations did not differ between exposed and unexposed boys. Eight prenatally exposed boys had genital malformations (no unexposed). These boys had smaller testis, shorter penile length and lower inhibin B concentrations than prepubertal boys without genital malformations. The findings support the results obtained at three months of age and indicate that prenatal pesticide exposure has long-term effects on reproductive function in boys.

Associations between congenital cryptorchidism in newborn boys and levels of dioxins and PCBs in placenta

In animal studies, exposure to dioxins has been associated with disrupted development of the male reproductive system, including testicular maldescent. Some polychlorinated biphenyls (PCBs) have also dioxin-like effects. In addition, one previous case-control study has reported an association between congenital cryptorchidism and colostrum PCB levels. We performed a case-control study to evaluate whether congenital cryptorchidism in boys was associated with increased levels of dioxins or PCBs in placenta reflecting foetal exposure. In addition, associations between placenta levels of these chemicals and reproductive hormone levels in boys at 3 months were studied. Placentas were collected in a Danish-Finnish joint prospective cohort study on cryptorchidism (1997-2001). The boys were examined for cryptorchidism at birth and at 3 months. Altogether, 280 placentas [112 Finnish (56 cases, 56 controls) and 168 Danish (39 cases, 129 controls)] were analysed for 17 toxic polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and 37 PCBs (including 12 dioxin-like PCBs). Infant serum samples taken at 3 months were analysed for reproductive hormones. No significant differences between cases and controls were observed in either country in dioxin WHO-TEq levels (median 9.78 vs. 8.47 pg/g fat, respectively, in Finland, and 11.75 vs. 10.88 pg/g fat in Denmark) or PCB WHO-TEq levels (median 2.12 vs. 2.15 pg/g fat in Finland, 2.34 vs. 2.10 pg/g fat in Denmark) or total-TEq levels (median 11.66 vs. 10.58 pg/g fat in Finland, 13.94 vs. 13.00 pg/g fat in Denmark). Placenta WHO-TEq levels of dioxins were not associated with infant reproductive hormone levels at 3 months. In Finland, PCB WHO-TEq levels in placenta associated positively with infant LH levels. WHO-TEq levels of dioxins and PCBs and total-TEq levels were higher in Danish than Finnish samples. In conclusion, no association between placenta levels of dioxins or PCBs and congenital cryptorchidism was found. Significant country differences in chemical levels were observed.

Heterozygous deletion at the RLN1 locus in a family with testicular germ cell cancer identified by integrating copy number variation data with phenome and interactome information

To search for disease-related copy number variations (CNVs) in families with a high frequency of germ cell tumours (GCT), we analysed 16 individuals from four families by array comparative genomic hybridization (aCGH) and applied an integrative systems biology algorithm that prioritizes risk-associated genes among loci targeted by CNVs. The top-ranked candidate, RLN1, encoding a Relaxin-H1 peptide, although only detected in one of the families, was selected for further investigations. Validation of the CNV at the RLN1 locus was performed as an association study using qPCR with 106 sporadic testicular GCT patients and 200 healthy controls. Observed CNV frequencies of 1.9% among cases and 1.5% amongst controls were not significantly different and this was further confirmed by CNV data extracted from a genome-wide analysis of 189 cases and 380 controls, where similar frequencies of 2.2% were observed in both groups (p=1). Immunohistochemistry for Relaxin-H1 (RLN1), Relaxin-H2 (RLN2) and their cognate receptor, RXFP1, detected one, and in some cases both, of the relaxins in Leydig cells, Sertoli cells and a subset of neoplastic germ cells, whereas the receptor was present in Leydig cells and spermatids. Collectively, the findings show that a heterozygous loss at the RLN1 locus is not a genetic factor mediating high population-wide risk for testicular germ cell tumour, but do not exclude a contribution of this aberration in some cases of cancer. The preliminary expression data suggest a possible role of the relaxin peptides in spermatogenesis and warrant further studies.

Recent adverse trends in semen quality and testis cancer incidence among Finnish men

Impaired semen quality and testicular cancer may be linked through a testicular dysgenesis syndrome of foetal origin. The incidence of testis cancer has been shown to increase among Finnish men, whereas there is no recent publication describing temporal trends in semen quality. Therefore, we carried out a prospective semen quality study and a registry study of testis cancer incidence among Finnish men to explore recent trends. A total of 858 men were investigated in the semen quality study during 1998–2006. Median sperm concentrations were 67 (95% CI 57–80) million/mL, 60 (51–71) and 48 (39–60) for birth cohorts 1979–81, 1982–83 and 1987; total sperm counts 227 (189–272) million, 202 (170–240) and 165 (132–207); total number of morphologically normal spermatozoa 18 (14–23) million, 15 (12–19) and 11 (8–15). Men aged 10–59 years at the time of diagnosis with testicular cancer during 1954–2008 were included in the registry study, which confirmed the increasing incidence of testicular cancer in recent cohorts. These simultaneous and rapidly occurring adverse trends suggest that the underlying causes are environmental and, as such, preventable. Our findings necessitate not only further surveillance of male reproductive health but also research to detect and remove the underlying factors.

Semen quality and reproductive hormone levels in men from Southern Spain

In North European countries, a significant difference in semen quality among young men has been shown. Men from the western countries, Denmark, Germany and Norway, have lower semen quality than men from the eastern countries Finland, Estonia and Lithuania. Similarly, men in the western countries have a higher risk of testicular cancer. According to the testicular dysgenesis syndrome (TDS) concept that suggests a link between risk of impaired semen quality and increased risk of testicular cancer, Spanish men would be expected to have a semen quality at a normal level because of their very low testis cancer risk. We therefore investigated 273 men from the Almeria region in the Southern Spain to test this hypothesis. The men delivered semen samples, underwent physical examinations, had a blood sample drawn and provided information on lifestyle and reproductive health parameters. The investigations took place from November 2001 to December 2002. Adjusting for effects of confounders, the median sperm concentration and total sperm count were 62 (95% confidence interval 47-82) million/mL and 206 (153-278) million, respectively. The median numbers of motile and morphologically normal spermatozoa assessed according to strict criteria were 59% (57-62%) and 9.4% (8.6-10.0%), respectively. The median total testosterone and calculated free androgen index were 28 nm (26-30) and 95 (88-103), respectively. Assuming that the investigated men, to a large extent, are representative of the population of young men the Southern Spain, the results show that these have normal semen quality and reproductive hormone levels as expected in a population with a low incidence of testicular cancer.

A novel double staining strategy for improved detection of testicular carcinoma in situ cells in human semen samples

Prompted by the recently reported expression of POU5F1 (OCT3/4) in epididymis, a panel of markers for carcinoma in situ (CIS) testis and testicular germ cell tumours (TGCT), including AP-2γ(TFAP2C), NANOG, OCT3/4, KIT, placental-like alkaline phosphatase (PLAP), M2A/PDPN and MAGE-A4 were examined by immunohistochemistry or in situ hybridisation in urogenital epithelia, which may interfere with detection of CIS cells in semen. In addition to OCT3/4, the expression of AP-2γ and NANOG or their variants was detected in urogenital epithelia, while other CIS markers, including PLAP/alkaline phosphatase were absent. A combination of immunocytological staining for AP-2γ or OCT3/4 and rapid cytochemical alkaline phosphatase reaction was subsequently developed. This approach was tested in 22 patients with TGCT. In 14 patients (63.6%), double stained cells were found and thus the method was proven suitable for the detection of CIS cells in semen. In conclusion, transcription factors related to pluripotency and undifferentiated state of cells, which most likely have several variants or modifications, are unexpectedly detected using currently available antibodies in urogenital epithelial cells which may be shed into semen. Combining the immunohistochemical nuclear markers with a rapid cytochemical alkaline phosphatase reaction for detection of CIS cells in ejaculates may provide a more reliable diagnostic method.

Hypothesis: exposure to endocrine-disrupting chemicals may interfere with timing of puberty

A recent decline in onset of puberty - especially among girls - has been observed, first in the US in the mid-1990s and now also in Europe. The development of breast tissue in girls occurs at a much younger age and the incidence of precocious puberty (PP) is increasing. Genetic factors and increasing prevalence of adiposity may contribute, but environmental factors are also likely to be involved. In particular, the widespread presence of endocrine-disrupting chemicals (EDCs) is suspected to contribute to the trend of earlier pubertal onset. The factors regulating the physiological onset of normal puberty are poorly understood. This hampers investigation of the possible role of environmental influences. There are many types of EDCs. One chemical may have more than one mode of action and the effects may depend on dose and duration of the exposure, as well as the developmental stage of the exposed individual. There may also be a wide range of genetic susceptibility to EDCs. Human exposure scenarios are complex and our knowledge about effects of mixtures of EDCs is limited. Importantly, the consequences of an exposure may not be apparent at the actual time of exposure, but may manifest later in life. Most known EDCs have oestrogenic and/or anti-androgenic actions and only few have androgenic or anti-oestrogenic effects. Thus, it appears plausible that they interfere with normal onset of puberty. The age at menarche has only declined by a few months whereas the age at breast development has declined by 1 year; thus, the time span from initiation of breast development to menarche has increased. This may indicate an oestrogen-like effect without concomitant central activation of the hypothalamic-pituitary axis. The effects may differ between boys and girls, as there are sex differences in age at onset of puberty, hormonal profiles and prevalence of precocius puberty.

Narrow intra-individual variation of maternal thyroid function in pregnancy based on a longitudinal study on 132 women

BACKGROUND

Adaptive alterations in maternal physiology cause changes in thyroid hormone levels throughout pregnancy, and precise biochemical evaluation is thus highly dependent on gestation-specific reference intervals and expected intra-individual variation.

OBJECTIVE

The aim of the study was the assessment of the intra-individual variation as well as the longitudinal course of thyroid hormones during normal pregnancy and factors that influence the normal reference range for thyroid function. For this purpose, a longitudinal statistical model was applied.

DESIGN

In a cohort of 132 pregnant women, serial blood samples were obtained and ultrasound scans were performed throughout pregnancy.

METHODS

Serum levels of TSH, free and total thyroxine (T(4)), free and total triiodothyronine (T(3)) as well as autoantibodies against thyroid peroxidase and thyroglobulin were measured in 979 serum samples.

RESULTS

Intra-individual variations of thyroid hormone concentrations were smaller than inter-individual variations (individuality index range: 0.38-0.71). Maternal height was positively associated with free T(4) (FT(4)) (b=0.003; P=0.031) and pre-pregnancy body mass index with T(3) and free T(3) (b=0.017; <0.001 and b=0.007; P<0.001). Smoking was positively associated with T(4) and FT(4), but it was modulated by gestational age. Gestation-specific reference intervals for thyroid function variables from autoantibody-negative participants are presented.

CONCLUSIONS

In accordance with the data from nonpregnant adults, intra-individual variations of thyroid hormones were smaller than inter-individual variations also during pregnancy. In the evaluation of thyroid function in pregnancy, the individual longitudinal course of thyroid hormones rather than absolute values should be considered. We present a longitudinal model for the prediction of maternal thyroid function tests in pregnant women.

Testicular dysgenesis syndrome: foetal origin of adult reproductive problems

The evidence for the existence of testicular dysgenesis syndrome (TDS) is presented in this review. Several epidemiological studies have shown that conditions like cryptorchidism, impaired spermatogenesis, hypospadias and testicular cancer can be associated as risk factors for each other. Thus, the risk of testis cancer is significantly increased in men with cryptorchidism and/or infertility. Several recent studies point towards early dysgenesis of the foetal testis as the biological link between these disorders. Dysgenesis has been demonstrated in biopsies of the contralateral testis of men with testis cancer and in infertile men. The histological evidence includes immature seminiferous tubules with undifferentiated Sertoli cells, microliths and Sertoli-cell only tubules. Dysgenetic testes often have an irregular ultrasound pattern, where microliths may also be visible. Our current hypothesis is that maternal exposure to endocrine disrupting chemicals may contribute to the pathogenesis of TDS. Animal experiments have shown that all TDS symptoms, except testicular cancer, can be induced by foetal exposure to anti-androgenic chemicals. However, the cause of TDS in humans remains to be determined.

Germ cell differentiation-dependent and stage-specific expression of LANCL1 in rodent testis

LANCL1 (LanC-like protein 1) is related to the bacterial LanC (lanthionine synthetase C) family, which is involved in the biosynthesis of antimicrobial peptides. Highest expression levels of LANCL1 are found in testes and brain, two organs that exist behind blood-tissue barriers. In the mouse, the establishment of an impermeable blood-testis barrier occurs between day 10-16 post natal (pn). Differential display analysis showed that the expression level of LANCL1 mRNA in mouse testes was very low until day 16 pn, but increased gradually from day 16 pn to reach a maximum on days 22-24 pn followed by a slight reduction from day 26 pn to adult animals. Thus, the expression of LANCL1 mRNA is initiated following the establishment of the blood-testis barrier. In situ hybridisation revealed that LANCL1 mRNA was induced in diplotene spermatocytes, which appear for the first time in mouse testes between days 18 and 20 pn, verifying the expression profile determined by differential display. LANCL1 mRNA level remained high in the meiotic division phase and in early round spermatids, but was down regulated in elongating spermatids and it was undetectable in step 9 elongating spermatids in stage IX (as defined by Russel et al., 1990). The steady decrease in expression level from round spermatids in stage I to elongating spermatids in stage IX suggested that LANCL1 mRNA was not transcribed in spermatids. LANCL1 expression in rat testes was initiated already in pachytene spermatocytes in stage IX, but otherwise similar to mouse.

Cryptorchidism as part of the testicular dysgenesis syndrome: the environmental connection

Cryptorchidism is part of the testicular dysgenesis syndrome (TDS), which includes other male reproductive disorders such as hypospadias, testis cancer and reduced semen quality. These diseases appear to be linked by common pathogenic mechanisms, interfering with normal fetal testis development. Testis development and descent is dependent on androgens and thus on an intact hypothalamus-pituitary-gonadal axis. Although cryptorchidism occurs in rare syndromes and genetic disorders, in the majority of children the etiology remains open. Many maternal and fetal risk factors have been previously identified but recently, scientific focus has also been directed to environmental hormone disrupting chemicals and lifestyle, as the prevalence of testis cancer and cryptorchidism has increased and semen quality decreased over few decades in several countries. Some persistent environmental chemicals, e.g. polychlorinated pesticides and polybrominated flame retardants, were associated with testicular maldescent and testis cancer. In addition, prenatal exposure to phthalates was negatively correlated to testosterone levels and anogenital distance as a measure of androgen effect in infant boys. Alcohol consumption and maternal smoking during pregnancy also appeared to be a risk factor for cryptorchidism. Thus, current evidence suggests that the development of the male reproductive tract may be susceptible to adverse effects of environmental hormone disrupters.

Low semen volume in 47 adolescents and adults with 47,XXY Klinefelter or 46,XX male syndrome

Klinefelter syndrome is characterized by progressive testicular failure causing androgen deficiency and azoospermia in most patients. The aim of this study was to evaluate semen quality in consecutive patients with an additional X chromosome as compared with healthy males. Forty-seven males with non-mosaic 47,XXY (n = 40) or SRY-positive 46,XX male (n = 7) karyotypes aged 26.1 (range: 15.0-51.7) years participated. Semen quality was compared with 2136 (control group I) men from the general population aged 18.9 (17.9-28.6) years and with 349 fertile men (control group II) aged 30.9 (22.0-43.8) years. Semen volume adjusted for duration of abstinence was significantly smaller in the patients [2.0 (0.2-5.7) mL] when compared with control group I [3.1 (0.3-12.5) mL, p < 0.0001] and group II [3.6 (0.6-12.5) mL, p < 0.0001]. There was no difference in semen volume between 47,XXY and 46,XX males. All patients had azoospermia except two 47,XXY males aged 29 years who had sperm concentrations of 0.5 and 1.6 million/mL, respectively. We found significantly smaller semen volume in the patients when compared with controls, and the presence of motile spermatozoa in two out of 47 patients. The small semen volume supports the notion of 47,XXY patients being androgen insufficient despite serum testosterone levels within the normal range.

Sons conceived by assisted reproduction techniques inherit deletions in the azoospermia factor (AZF) region of the Y chromosome and the DAZ gene copy number

BACKGROUND

Deletions in the azoospermia factor (AZF) region of the Y chromosome are frequent in infertile men. The clinical consequences and the mode of inheritance of these deletions are not yet clear.

METHODS

Y chromosome deletion mapping and quantitative PCR analysis of the DAZ-gene copy number, supplemented with haplogroup typing in deleted patients, were performed, in combination with clinical assessments in 264 fathers and their sons conceived by assisted reproduction techniques (ART), and in 168 fertile men with normal sperm concentration.

RESULTS

In the ART fathers group, a complete AZFc deletion was detected in 0.4% (1/264). AZFc rearrangements/polymorphisms were found in 6.8% (18/264; 95% CI: 4.4-10.5), which was significantly more frequent (P = 0.021) than in the controls (3/168; 1.8%, 95% CI: 0.6-5.1). All deletions were transmitted to the sons, without any clinical symptoms in early childhood. In the fathers, there was no significant correlation between the DAZ copy number and the severity of spermatogenic failure.

CONCLUSIONS

AZFc rearrangements/polymorphisms are transmitted to sons and may represent a risk factor for decreased testis function and male subfertility, which needs confirmation in further studies in larger cohorts. However, deletions of two DAZ gene copies are compatible with normal spermatogenesis and fertility.

Testicular dysgenesis syndrome and Leydig cell function

Fertility among human beings appear to be on the decline in many Western countries, and part of the explanation may be decreasing male fecundity. A hypothesis has been put forward that decreasing semen quality may be associated with a testicular dysgenesis syndrome (TDS), a spectrum of disorders originating in early foetal life. TDS comprises various aspects of impaired gonadal development and function, including testicular cancer. A growing body of evidence, including animal models and research in human beings, points to lifestyle factors and endocrine disrupters as risk factors for TDS. We present our view of the emerging role of Leydig cell dysfunction with subsequent decreased testosterone levels in the pathogenesis of TDS.

Adverse trends in male reproductive health: we may have reached a crucial 'tipping point'

Healthy men produce an enormous number of sperms, far more than necessary for conception. However, several studies suggest that semen samples where the concentration of sperms is below 40 mill/mL may be associated with longer time to pregnancy or even subfertility, and specimens where the concentration of sperms is below 15 mill/mL may carry a high risk of infertility. Historic data from the 1940s show that the bulk of young men at that time had sperm counts far above 40 mill/mL with averages higher than 100 mill/mL. However, recent surveillance studies of young men from the general populations of young men in Northern Europe show that semen quality is much poorer. In Denmark approximately 40 percent of the men have now sperm counts below 40 mill/mL. A simulation assuming that average sperm count had declined from 100 mill/mL in ‘old times’ to a current level close to 40 mill/mL indicated that the first decline in average sperm number of 20–40 mill/mL might not have had much effect on pregnancy rates, as the majority of men would still have had counts far above the threshold value. However, due to the assumed decline in semen quality, the sperm counts of the majority of 20 year old European men are now so low that we may be close to the crucial tipping point of 40 mill/mL spermatozoa. Consequently, we must face the possibility of more infertile couples and lower fertility rates in the future.

Normal bone mineral content but unfavourable muscle/fat ratio in Klinefelter syndrome

OBJECTIVE

To evaluate body composition and bone mineral content (BMC) in children and adolescents with Klinefelter syndrome (KS).

DESIGN

Retrospective cross-sectional study.

SETTING

Tertiary endocrine clinic at the University Hospital, Copenhagen.

PATIENTS

Eighteen untreated boys with KS and six boys with KS receiving androgen substitution with a median age of 11.0 years (range 4.3-18.6) participated in the study.

INTERVENTION

Dual energy x ray absorptiometry and anthropometric measurements were analysed.

MAIN OUTCOME MEASURES

Lumbar and whole body BMC, lean body mass (LBM), body fat mass (BFM), body fat percentage (BF%), height and body mass index (BMI) were compared between treated and untreated boys with KS and compared to normal age-matched boys.

RESULTS

LBM (untreated -0.3 (-2.4 to +2.1) and treated +1.1 (-1.6 to +2.1)) was normal, while BFM (untreated +0.5 (-1.0 to +2.3), p = 0.02 and treated +1.6 (-0.2 to +2.4), p = 0.01) was significantly increased, all expressed as standard deviation scores. Lumbar bone mineral density (BMD; untreated -0.4 (-3.1 to +0.9) and treated +1.0 (-1.4 to +3.0)) and whole body BMC (untreated +0.1 (-1.8 to +3.3) and treated +1.5 (-1.1 to +2.5)) were normal.

CONCLUSION

We found significantly increased BFM and BF% despite normal LBM, suggesting the presence of an unfavourable muscle/fat ratio. Lumbar BMD and whole body BMC were normal. These findings suggest that the unfavourable metabolic profile seen in adult KS may already be present in childhood as evidenced by the increased fat mass, whereas the reported low BMD seems to develop after puberty.