Summary Published trends and geographical differences in cryptorchidism rates are almost exclusively derived from hospital‐based birth defect registers, which are sensitive to selection bias and incomplete reporting. This study aimed to accurately assess the cryptorchidism prevalence in the general population of Rotterdam. Of 7652 consecutive male live births, 7292 (95%) were examined for cryptorchidism at Child Healthcare Centres around the age of 1 month. In a subgroup of cases, the persistence of cryptorchidism was re‐assessed during a follow‐up examination by expert specialists. The cryptorchidism rate at the median age of 35 days was 1.2% (89/7292). In the re‐examined subgroup (median age 95 days) 69% of the boys (24/35) had persistent cryptorchidism, of which 20 were unilateral and four bilateral. The population rate of 1.2% falls within the range of 0.9–9% reported by others. Differences in case ascertainment and population characteristics probably explain part of the differences between studies. Our cross‐sectional design does not allow for analysis of a temporal trend, but provides a baseline for future trend studies. To study cryptorchidism rates, trends, and risk factors, a systematic case ascertainment is warranted.
Abstract Previous studies suggest that pregnant women and children are particularly vulnerable to the adverse effects of air pollution. A prospective cohort study in pregnant women and their children enables identification of the specific effects and critical periods. This paper describes the design of air pollution exposure assessment for participants of the Generation R Study, a population-based prospective cohort study from early pregnancy onwards in 9778 women in the Netherlands. Individual exposures to PM 10 and NO 2 levels at the home address were estimated for mothers and children, using a combination of advanced dispersion modelling and continuous monitoring data, taking into account the spatial and temporal variation in air pollution concentrations. Full residential history was considered. We observed substantial spatial and temporal variation in air pollution exposure levels. The Generation R Study provides unique possibilities to examine effects of short- and long-term air pollution exposure on various maternal and childhood outcomes and to identify potential critical windows of exposure.
Subfertility affects about 15% of all couples. Assessment of spermatogenesis has a central role in the evaluation of the subfertile couple. Classical markers of spermatogenesis, such as semen analysis, testicular biopsy and endocrine evaluation all have their diagnostic limitations. There is a clear need for accurate additional markers of spermatogenesis. Recently, the serum inhibin B level has emerged as a sensitive endocrine marker of spermatogenesis. This paper summarises the prosand consof different markers of spermatogenesis, with specific focus on serum inhibin B. The serum inhibin B level has been shown to be associated with classical markers of spermatogenesis, particularly testicular histology, and to be the most accurate endocrine marker of spermatogenesis. A subnormal serum inhibin B level clearly reflects disturbed spermatogenesis. Before puberty, when no spermatogenesis takes place, inhibin B is a marker of testicular integrity. Clinical applications of serum inhibin B in childhood and adulthood are given, and a view on future directions and research is presented. The serum inhibin B level has proven to be valuable in the evaluation of spermatogenesis, and holds a promise for further research.
The purpose of this study is to increase our understanding of environmental correlates that are associated with route choice during active transportation to school (ATS) by comparing characteristics of actual walking and cycling routes between home and school with the shortest possible route to school. Children (n = 184; 86 boys, 98 girls; age range: 8–12 years) from seven schools in suburban municipalities in the Netherlands participated in the study. Actual walking and cycling routes to school were measured with a GPS-device that children wore during an entire school week. Measurements were conducted in the period April–June 2014. Route characteristics for both actual and shortest routes between home and school were determined for a buffer of 25 m from the routes and divided into four categories: Land use (residential, commercial, recreational, traffic areas), Aesthetics (presence of greenery/natural water ways along route), Traffic (safety measures such as traffic lights, zebra crossings, speed bumps) and Type of street (pedestrian, cycling, residential streets, arterial roads). Comparison of characteristics of shortest and actual routes was performed with conditional logistic regression models. Median distance of the actual walking routes was 390.1 m, whereas median distance of actual cycling routes was 673.9 m. Actual walking and cycling routes were not significantly longer than the shortest possible routes. Children mainly traveled through residential areas on their way to school (>80 % of the route). Traffic lights were found to be positively associated with route choice during ATS. Zebra crossings were less often present along the actual routes (walking: OR = 0.17, 95 % CI = 0.05–0.58; cycling: OR = 0.31, 95 % CI = 0.14–0.67), and streets with a high occurrence of accidents were less often used during cycling to school (OR = 0.57, 95 % CI = 0.43–0.76). Moreover, percentage of visible surface water along the actual route was higher compared to the shortest routes (walking: OR = 1.04, 95 % CI = 1.01–1.07; cycling: OR = 1.03, 95 % CI = 1.01–1.05). This study showed a novel approach to examine built environmental exposure during active transport to school. Most of the results of the study suggest that children avoid to walk or cycle along busy roads on their way to school.
Prenatal exposure to bisphenol A (BPA) has been associated with adverse birth outcomes, but findings of previous studies have been inconsistent.We investigated the relation of prenatal BPA exposure with intrauterine growth and evaluated the effect of the number of measurements per subject on observed associations.This study was embedded in a Dutch population-based prospective cohort study, with urine samples collected during early, mid-, and late pregnancy. The study comprised 219 women, of whom 99 had one measurement, 40 had two measurements, and 80 had three measurements of urinary BPA. Fetal growth characteristics were repeatedly measured by ultrasound during pregnancy and combined with measurements at birth. Linear regression models for repeated measurements of both BPA and fetal growth were used to estimate associations between urinary concentrations of creatinine-based BPA (BPACB) and intrauterine growth.The relationship between BPACB and fetal growth was sensitive to the number of BPA measurements per woman. Among 80 women with three BPA measurements, women with BPACB > 4.22 μg/g crea (creatinine) had lower growth rates for fetal weight and head circumference than did women with BPACB < 1.54 μg/g crea, with estimated differences in mean values at birth of -683 g (20.3% of mean) and -3.9 cm (11.5% of mean), respectively. When fewer measurements were available per woman, the exposure-response relationship became progressively attenuated and statistically nonsignificant.Our findings suggest that maternal urinary BPA may impair fetal growth. Because previous studies have shown contradictory findings, further evidence is needed to corroborate these findings in the general population.
Natural environments (NE) are promoted as places that support physical activity (PA), but evidence on PA distribution across various types and sizes of NE is lacking. Accelerometers and GPS-devices measured PA of Dutch general population adults aged 45-65 years (N=279). Five NE types were distinguished: 'parks', 'recreational area', 'agricultural green', 'forest & moorland', and 'blue space', and four categories of size: 0-3, 3-7, 7-27, and ≥27 ha. Modality (i.e. spatially concentrated PA, walking, jogging, and cycling) and intensity (i.e. sedentary behavior, LPA, and MVPA) of PA varied significantly between NE types. Compared to parks, less sedentary behavior and walking but more spatially concentrated PA was observed in recreational areas and green space. Cycling levels were found to be significantly lower in recreational areas and forest & moorland, but higher in blue space as compared to parks. Larger sized NE (≥7 ha) were associated with higher levels of MVPA, walking, jogging and cycling. Insight in which environments (according to type and size) facilitate PA, contributes to the development of tailored PA promoting interventions with ensuing implications for public health.
