Trynke Hoekstra

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A gold standard that defines the presence of a subclinical varicocele does not exist. No one has accurately demonstrated at what diameter an internal spermatic vein becomes palpable. We correlated the clinical examination of the scrotum with ultrasonographic measurements of internal spermatic vein diameter and reversal of venous flow in 156 testicles. The(More)
Cardiovascular diseases and diabetes mellitus type II (DM II) are both major health problems. A large risk factor for these diseases is the presence of the metabolic syndrome. It is known that the risk of DM II can be decreased by coffee consumption. Therefore, we examined the association between coffee consumption and the components of the metabolic(More)
OBJECTIVE To identify distinct developmental patterns of diabetic retinopathy (DR) and assess the risk factor levels of patients in these clusters. RESEARCH DESIGN AND METHODS A cohort of 3,343 patients with type 2 diabetes mellitus (T2DM) monitored and treated in the Diabetes Care System West-Friesland, the Netherlands, was followed from 2 to 6 years.(More)
AIM To assess longitudinally whether smoking tobacco is related to muscle strength in healthy adults and to assess the influence of lifestyle covariates on this relation. METHODS Data were obtained from the observational Amsterdam Growth and Health Longitudinal Study, with four repeated measurements at the ages of 21 (n = 181), 27 (n = 144), 32 (n = 426)(More)
PURPOSE The traditional approach for identifying subjects at risk from cardiovascular diseases (CVD) is to determine the extent of clustering of biological risk factors adjusted for lifestyle. Recently, markers of endothelial dysfunction and low grade inflammation, including high sensitivity C-reactive protein (hsCRP), soluble intercellular adhesion(More)
OBJECTIVE To identify different life satisfaction trajectories in the period between the start of active spinal cord injury (SCI) rehabilitation and 5 years after discharge, and to find predictors for distinguishing between trajectories. The hypotheses were that different life satisfaction trajectories would be identified and that demographic, lesion,(More)
Major depression is prevalent after traumatic brain injury (TBI) and associated with poor outcomes. Little is known about the course of depression after TBI. Participants were 559 consecutively admitted patients with mild to severe TBI recruited from inpatient units at Harborview Medical Center, a Level I trauma center in Seattle, WA. Participants were(More)
Measurement invariance of the 2-factor model of the Perceived Stress Scale--10-item version (Cohen & Williamson, 1988) was tested across men and women at two time points and in the combined total sample over a 2-year time frame (n = 871). Measurement invariance results indicated that the scale measured the latent factors, stress and counter-stress,(More)
The Amsterdam Growth and Health Longitudinal Study (AGHLS) is a unique, multidisciplinary cohort study that was initially set up to examine growth and health among teenagers. Throughout the years, the AGHLS has aimed to answer research questions dealing with the relationships between the (natural) development of anthropometry, lifestyle and health from(More)
PURPOSE In men considered to have azoospermia by routine semen analyses sperm may be identified after centrifuging the semen. Because these sperm may be used for intracytoplasmic sperm injection, we describe our technique and findings of sperm pelleting. MATERIALS AND METHODS Semen centrifugation for sperm pellet analysis was performed in 140 consecutive(More)