Low-saturated-fat and low-cholesterol diet does not alter pubertal development and hormonal status in adolescents.

AIM: The aim was to assess the influence of dietary counselling on the pubertal development and hormonal status in healthy adolescents. METHODS: We used a subcohort of 193 healthy boys (52%) and girls (48%) from the Special Turku Coronary Risk Factor Intervention Project. Participants were recruited by nurses at the well-baby clinics in Turku Finland in 1990-1992 and randomised into intervention and control groups. Intervention children received low-saturated fat and low-cholesterol dietary counselling initiated at seven months of age. Participants were examined once a year with Tanner staging, anthropometric measurements and serial reproductive hormones from 10 to 19 years of age. In girls, postmenarcheal hormones were not analysed. RESULTS: Pubertal hormones in boys or girls did not differ between the intervention and control groups. However, we observed slight differences in pubertal progression by Tanner staging and in anthropometric parameters. The intervention boys progressed faster to G4 (p = 0.008), G5 (p = 0.008) and P5 (p = 0.03). The intervention boys were taller than control boys (p = 0.04), while weight and body mass index did not differ. CONCLUSION: Dietary intervention did not affect pubertal hormonal status. This finding supports the safety of implemented counselling in respect to puberty.

Semen quality improves marginally during young adulthood: a longitudinal follow-up study.

STUDY QUESTION: Does semen quality improve during early adulthood? SUMMARY ANSWER: Semen variables change little during the third decade of life, however some improvement in sperm morphology and motility may occur. WHAT IS KNOWN ALREADY: A suspicion of deteriorating semen quality has been raised in several studies. The longitudinal development of semen quality in early adulthood is insufficiently understood. STUDY DESIGN, SIZE, DURATION: A longitudinal follow-up of two cohorts of volunteer young adult Finnish men representing the general population was carried out. Cohorts A (discovery cohort, born 1979-1981, n = 336) and B (validation cohort, born 1983, n = 197) were followed up from the age of 19 years onward for 10 years. PARTICIPANTS/MATERIALS, SETTING, METHODS: Inclusion criteria included that both the men and their mothers were born in Finland. Semen analysis was performed in cohorts A and B at 2-4 year intervals over a period of 10 years. Semen volume, sperm concentration, total sperm count, motility, total motile count and morphology were the variables assessed in the analysis. A physical examination was carried out at each visit to detect any significant andrological abnormalities. The overall participation rate was 13.4%. MAIN RESULTS AND THE ROLE OF CHANCE: During the follow-up, the percentage of sperm with normal morphology and the percentage of motile sperm increased significantly both in the discovery (A) (P < 0.001 at 19 versus 29 years for both) and validation (B) (P < 0.001 and P = 0.03 at 19 versus 29 years, respectively) cohort. Sperm concentration and total sperm count showed a significant increase with age only in cohort B (P = 0.03 at 21 versus 29 years, P = 0.009 at 19 versus 29 years, respectively). LIMITATIONS, REASONS FOR CAUTION: A limited number of men participated both in the first round and in the final fourth round (cohort A, n = 111 and cohort B, n = 90 men) and in all four rounds (cohort A, n = 61 and cohort B, n = 52). WIDER IMPLICATIONS OF THE FINDINGS: Almost full spermatogenic capacity is reached by the age of 19 years. However, the improvement in sperm motility and morphology during early adulthood may slightly improve male fecundity. STUDY FUNDING/COMPETING INTERESTS: This study was supported by the European Commission (QLK4-CT-1999-01422, QLK4-CT-2001-00269, QLK4-2002-0063, FP7/2008-2012: DEER 212844), The Danish Medical Research Council (9700833, 9700909), Danish Agency for Science (Technology and Innovation 09-067180), the Svend Andersen's Foundation, Velux Foundation, and Novo Nordisk Foundation, the Turku University Hospital, Sigrid Jusélius Foundation and the Academy of Finland. There are no conflicts of interest.

Reproductive Markers of Testicular Function and Size During Puberty in Boys With and Without a History of Cryptorchidism.

CONTEXT: Longitudinal data on levels of hypothalamic-pituitary-gonadal axis hormones and insulin-like growth factor I (IGF-I) during puberty in boys with a history of cryptorchidism are largely missing. OBJECTIVE: We aimed to compare pubertal hormone levels between boys with a history of congenital cryptorchidism who experienced spontaneous testicular descent or underwent orchiopexy and boys without a history of cryptorchidism. METHODS: This was a nested case-control study within a population-based birth cohort, with a prospective, longitudinal pubertal follow-up every 6 months (2005 to 2019). Participants were 109 Finnish boys, including boys with a history of unilateral cryptorchidism who underwent orchiopexy (n = 15), unilateral cryptorchidism who had spontaneous testicular descent (n = 15), bilateral cryptorchidism who underwent orchiopexy (n = 9), bilateral cryptorchidism who had spontaneous testicular descent (n = 7), and controls (n = 63). Serum reproductive hormone levels and testicular volumes were measured. RESULTS: From around onset of puberty, boys with bilateral cryptorchidism who underwent orchiopexy had significantly higher follicle-stimulating hormone (FSH) and lower inhibin B levels than controls. Boys with unilateral cryptorchidism who underwent orchiopexy had significantly higher FSH than controls, whereas inhibin B levels were similar. Testosterone, luteinizing hormone, insulin-like factor 3, and IGF-I were generally similar between groups. Testicular volume of boys with unilateral or bilateral cryptorchidism who underwent orchiopexy was smaller than that of the controls from 1 year after pubertal onset (P < 0.05). CONCLUSION: Cryptorchid boys, particularly those with bilateral cryptorchidism who underwent orchiopexy, had altered levels of serum biomarkers of Sertoli cells and germ cells and smaller testicular volumes compared with controls.

Metformin Treatment Does Not Affect Testicular Size in Offspring Born to Mothers with Gestational Diabetes.

OBJECTIVES: Studies in rodents suggest that metformin treatment during pregnancy may have harmful effects on testicular development in offspring. Our aim was to determine whether metformin treatment of gestational diabetes mellitus (GDM) affects testicular size in male offspring. METHODS: We compared the testicular size in prepubertal boys born to mothers who participated in a randomized controlled trial (RCT) comparing metformin with insulin in the treatment of GDM. Twenty-five (42.4% of invited) and 27 (52.9% of invited) boys whose mothers had been treated with metformin or insulin, respectively, participated in the study. Testicular size was measured by a ruler, an orchidometer, and by ultrasonography at the age of 33 to 85 months. RESULTS: The mean age of the boys was 60 months at the time of examination, and did not differ between the metformin and insulin group (p = 0.88). There was no difference in testicular size between the boys in the two groups (p always ≥ 0.40), and there were no significant differences in height, weight, BMI, BMI z-score, or waist-to-hip ratio (WHR) between the boys in the groups. CONCLUSIONS: Prepubertal testicular size did not differ between offspring born to metformin-treated mothers and those born to insulin-treated mothers.

Testicular Growth During Puberty in Boys With and Without a History of Congenital Cryptorchidism.

CONTEXT: The pattern of testicular growth during puberty may provide important information about early testicular damage and reproductive potential in adulthood. OBJECTIVE: To evaluate pubertal testicular growth in boys with congenital cryptorchidism and controls. DESIGN: Longitudinal case-control study. SETTING: Andrological Research Center, University of Turku. PARTICIPANTS: Altogether, 119 boys participated: 51 cases with a history of congenital cryptorchidism and 65 controls fulfilled the inclusion criteria. INTERVENTION: None. MAIN OUTCOME MEASURES: Testicular volume by an orchidometer (mL) and ultrasound (mL), testicular length by a ruler (mm), and onset of pubertal testicular growth (y). Longitudinal testicular growth was analyzed with a nonlinear mixed-effect model. RESULTS: The mean age of the onset of pubertal testicular growth (age at the attainment of >3 mL by orchidometer) was 11.7 and 11.8 years in cryptorchid cases and controls, respectively. The difference between cases and controls was not significant. Modeled postpubertal testicular size was smaller among bilaterally and unilaterally undescended testis than in controls. There was a high level of agreement between testicular sizes of 3 mL by orchidometer and 25 mm by ruler as cut-offs in definition of the onset of puberty. An orchidometer size of 3 mL and ruler length of 25 mm corresponded to 1.6 and 1.7 mL by ultrasound (with Lambert's formula), respectively. CONCLUSIONS: Testicular growth in puberty was impaired in congenitally cryptorchid boys. This suggests a poor perinatal development of the cryptorchid testis. The timing of the onset of pubertal testicular growth, however, did not differ which suggests an intact hypothalamic-pituitary axis.

Prenatal exposure to smoking and male reproductive health.

PURPOSE OF REVIEW: To assess whether prenatal exposure to smoking is associated with impaired reproductive health in exposed men. RECENT FINDINGS: Men who have been exposed to maternal smoking in utero have smaller testes and impaired semen quality as compared to nonexposed men, suggesting toxic effects on Sertoli and/or germ cells. According to meta-analyses there is only a weak or no association with fetal exposure to smoking and the incidence of testicular germ cell cancer, cryptorchidism, or hypospadias. SUMMARY: Adverse effect of maternal smoking on sperm production capacity of their son is yet another good reason for women to quit smoking before pregnancy.

Multilayer resonant subwavelength gratings: effects of waveguide modes and real groove profiles.

The boundary integral equation code PCGrate-S(X) is used to analyze diffraction on Hubble Space Telescope Cosmic Origins Spectrograph gratings at different boundary shapes and layer thicknesses. An effect of resonance anomalies excited in nonconformal dielectric layers overcoated on the surface of metallic grating on the efficiency is studied for the first time to our knowledge. Refractive indices (RIs) for bulk MgF2 taken from well-known references are found to be not suitable for thin optical layers at wavelengths between 115 and 170 nm. A method based on scale fitting of calculated and measured grating efficiencies is outlined for derivation of thin-film optical constants at hard to measure wavelengths. The calculated efficiency based on real boundary profiles and derived RIs of the G185M subwavelength grating is shown to fit within 9.6% or better to the measured data.