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Featured researches published by O. Valkenburg.


Human Reproduction | 2009

Genetic polymorphisms of GnRH and gonadotrophic hormone receptors affect the phenotype of polycystic ovary syndrome

O. Valkenburg; André G. Uitterlinden; D. Piersma; A. Hofman; Axel P. N. Themmen; F.H. de Jong; B.C.J.M. Fauser; Joop S.E. Laven

BACKGROUND Polycystic ovary syndrome (PCOS) is a complex genetic disorder. Multiple functional polymorphisms have been identified in genes that regulate the hypothalamic-pituitary-gonadal (HPG) axis that regulates ovarian function. The present study aims to examine the influence of genetic variants of the HPG-axis on the severity of clinical features of PCOS and disease susceptibility. METHODS We included 518 Caucasian PCOS women and 2996 unselected controls from the general population (the Rotterdam study). Genotype distributions were compared between patients and controls. Subsequently, associations with clinical features of PCOS were studied. Single nucleotide polymorphisms were selected in GnRH (Trp16Ser [rs6185]), the FSH-receptor (FSHR, Ala307Thr [rs6165] and Asn680Ser [rs6166]) and the LH-receptor (18insLQ, Asn291Ser [rs12470652] and Ser312Asn [rs2293275]). RESULTS FSHR Ser(680) was associated with higher levels of gonadotrophic hormones (FSH: P < 0.01, LH: P = 0.01), and testosterone (P = 0.05) and a higher frequency of hyperandrogenism (P = 0.04). No differences in risk for PCOS in association with the FSH-receptor variants were observed. CONCLUSION Genetic variants of the HPG-axis were associated with a modest but significant effect on the phenotype of PCOS. FSHR variants were strongly associated with the severity of clinical features of PCOS, such as levels of gonadotrophic hormones and the presence of hyperandrogenism, but not disease risk.


Human Reproduction | 2010

Psychological well-being and sexarche in women with polycystic ovary syndrome.

J.E. de Niet; C.M. de Koning; H. Pastoor; H.J. Duivenvoorden; O. Valkenburg; M.J. Ramakers; Jan Passchier; C. de Klerk; Joop S.E. Laven

BACKGROUND The characteristics of polycystic ovary syndrome (PCOS) such as hyperandrogenism and anovulation can be highly stressful and might negatively affect psychological well-being and sexuality. The objective of this study was to evaluate the association between PCOS characteristics and psychological well-being as well as sexarche. METHODS Patients (n = 1148) underwent standardized clinical evaluation. Psychological well-being was investigated in 480 patients with the Rosenberg self-esteem scale (RSES), the body cathexis scale (BCS) and the fear of negative appearance evaluation scale (FNAES). Sexarche was also assessed. RESULTS Amenorrhoea was associated with lower self-esteem (P = 0.03), greater fear of negative appearance evaluation (P = 0.01) and earlier sexarche (P= 0.004). Hyperandrogenism and acne were associated with poorer body satisfaction (P = 0.03, 0.02, respectively). Hirsutism and BMI were negatively associated with all psychological variables (RSES, P = 0.01; BCS, P = 0.05; FNAES, P = 0.02 and RSES, P = 0.03; BCS, P = 0.001; FNAES, P = 0.03, respectively). CONCLUSIONS Our results suggest that menstrual irregularities might be related to sexarche. Moreover, this study stresses that the treatment of women with PCOS should notably focus on physical but also on psychological and sexual characteristics.


Fertility and Sterility | 2009

The phenotype of polycystic ovary syndrome ameliorates with aging

Zoe Brown; Yvonne V. Louwers; Sharon Lie Fong; O. Valkenburg; Erwin Birnie; Frank H. de Jong; Bart C.J.M. Fauser; Joop S.E. Laven

OBJECTIVE To assess the effects of aging on the features of polycystic ovary syndrome (PCOS). DESIGN Retrospective longitudinal follow-up study. SETTING Tertiary care center. PATIENT(S) Patients with PCOS, diagnosed according to the 2003 Rotterdam criteria, who visited the outpatient clinic on consecutive occasions with a minimum interval of 6 months. INTERVENTION(S) Comparisons were made between the first visit and the consecutive visit grouped by intervals. MAIN OUTCOME MEASURE(S) Changes in clinical and endocrine characteristics. RESULT(S) A total of 254 women visited the outpatient clinic on 2 occasions each. Consecutive visits were grouped into 0.5 to 3.9 years (n = 172; mean follow-up, 2.6 years) and 4.0 to 7.0 years (n = 82; mean follow-up, 5.5 years). At their second visit, significantly more women had regained a regular cycle. The total antral follicle count was similar. Serum levels of testosterone, androstenedione, and dehydroepiandrosterone sulfate had decreased significantly. Plasma glucose levels had increased, whereas serum insulin levels and homeostasis model assessment score had significantly decreased. CONCLUSION(S) The PCOS phenotype changed with aging, suggesting an amelioration of the phenotype and ovarian dysfunction as indicated by the increase in number of regular menstrual cycles, decrease in serum androgen levels, and decrease in insulin resistance.


The Journal of Clinical Endocrinology and Metabolism | 2011

Fertility and Ovarian Function in High-Dose Estrogen-Treated Tall Women

A. E. J. Hendriks; Joop S.E. Laven; O. Valkenburg; S. Lie Fong; Bart C. J. M. Fauser; M. A. J. de Ridder; F. H. de Jong; Jenny A. Visser; A.M. van Ginneken; Annemieke M. Boot; S. L. S. Drop

BACKGROUND/OBJECTIVE High-dose estrogen treatment to reduce final height of tall girls has been shown to interfere with fertility. Ovarian function has not been studied. We therefore evaluated fertility and ovarian function in tall women who did or did not receive such treatment in adolescence. METHODS This was a retrospective cohort study of 413 tall women aged 23-48 yr, of whom 239 women had been treated. A separate group of 126 fertile, normoovulatory volunteers aged 22-47 yr served as controls. RESULTS Fertility was assessed in 285 tall women (157 treated, 128 untreated) who had attempted to conceive. After adjustment for age, treated women were at increased risk of experiencing subfertility [odds ratio (OR) 2.29, 95% confidence interval (CI) 1.38-3.81] and receiving infertility treatments (OR 3.44, 95% CI 1.76-6.73). Moreover, fecundity was notably affected because treated women had significantly reduced odds of achieving at least one live birth (OR 0.26, 95% CI 0.13-0.52). Remarkably, duration of treatment was correlated with time to pregnancy (r = 0.23, P = 0.008). Ovarian function was assessed in 174 tall women (119 treated, 55 untreated). Thirty-nine women (23%) exhibited a hypergonadotropic profile. After adjusting for age category, treated women had significantly higher odds of being diagnosed with imminent ovarian failure (OR 2.83, 95% CI 1.04-7.68). Serum FSH levels in these women were significantly increased, whereas antral follicle counts and serum anti-Müllerian hormone levels were decreased. CONCLUSION High-dose estrogen-treated tall women are at risk of subfertility in later life. Their fecundity is significantly reduced. Treated women exhibit signs of accelerated ovarian aging with concomitant follicle pool depletion, which may be the basis of the observed subfertility.


Menopause | 2008

Lipid profile of women with premature ovarian failure

Erik A. H. Knauff; Hendrika E. Westerveld; Angelique J. Goverde; Marinus J.C. Eijkemans; O. Valkenburg; Evert J. P. van Santbrink; Bart C.J.M. Fauser; Yvonne T. van der Schouw

Objective: Earlier menopause is associated with a higher incidence of cardiovascular events later in life. Concurrent with the ages of menopausal transition, a shift in lipid profile takes place. Premature ovarian failure (POF) or premature menopause allows us to study the effect of cessation of ovarian function on the lipid profile independent of effects of advanced chronological age. Design: Fasting triglycerides (TGs), total high-density lipoprotein (HDL), and low-density lipoprotein cholesterol levels were measured in 90 women with POF not using any hormone therapy and 198 population controls of the same age range not using oral contraceptives. Correlations between lipids and ovarian function parameters were assessed. Results: After correction for age, body mass index, and smoking, women with POF presented with significantly higher TG levels (mean difference: 0.17 log mmol/L [95% CI: 0.06-0.29]). HDL cholesterol levels were borderline significantly lower in women with POF. No age-corrected correlation between triglycerides or other lipids and estradiol levels or time of estrogen deprivation could be identified. However, the free androgen index, sex hormone-binding globulin, and testosterone concentrations showed significant correlations with TGs and/or HDL cholesterol concentrations. Conclusions: Loss of ovarian function at a very young age (POF) coincides with subtle changes in the lipid profile (higher TG levels and marginally lower HDL). Androgens (increased free androgen index and testosterone and decreased sex hormone-binding globulin) are better markers for unfavorable lipid changes compared with estrogen levels or duration of estrogen deprivation in women with POF. Elevated TG levels in combination with increased (free) androgens may be an early manifestation of reduced insulin sensitivity.


Human Reproduction | 2008

Variants in the ACVR1 gene are associated with AMH levels in women with polycystic ovary syndrome

Marlies E. Kevenaar; Axel P. N. Themmen; Anke van Kerkwijk; O. Valkenburg; André G. Uitterlinden; Frank H. de Jong; Joop S.E. Laven; Jenny A. Visser

BACKGROUND Polycystic ovaries display an increased number of pre-antral and antral follicles compared with normal ovaries, suggesting that early and late follicle development are disturbed. The pathophysiology of this process is poorly understood. Since the transforming growth factor beta family members, anti-Müllerian hormone (AMH) and bone morphogenetic proteins (BMPs), inhibit FSH sensitivity, their signalling may contribute to the aberrant follicle development in these women. Here, we investigated the role of ALK2, a type I receptor for AMH/BMP signalling, in PCOS using a genetic approach. METHODS Seven single nucleotide polymorphisms in the ACVR1 gene, encoding ALK2, were genotyped in 359 PCOS patients and 30 normo-ovulatory and 3543 population-based control women, and haplotypes were determined. Subsequently, the association of ACVR1 variants with ovarian parameters and hormone levels was investigated. RESULTS The polymorphisms rs1220134, rs10497189 and rs2033962 and their corresponding haplotypes did not show different frequencies from controls, but were associated with AMH levels in PCOS women (P = 0.001, P = 0.002 and P = 0.007, respectively). Adjustment for follicle number revealed that the association with AMH levels was, in part, independent from follicle number, suggesting that variants in ACVR1 also influence AMH production per follicle. CONCLUSIONS Genetic variation within ACVR1 is associated with AMH levels and follicle number in PCOS women, suggesting that ALK2 signalling contributes to the disturbed folliculogenesis in PCOS patients.


The Journal of Clinical Endocrinology and Metabolism | 2010

Oligoovulatory and anovulatory cycles in women with polycystic ovary syndrome (PCOS): what's the difference?

Janneke A. Burgers; Sharon Lie Fong; Yvonne V. Louwers; O. Valkenburg; Frank H. de Jong; Bart C. J. M. Fauser; Joop S.E. Laven

CONTEXT Polycystic ovary syndrome (PCOS) is a heterogeneous disorder. The phenotype may differ between patients who exhibit signs of recent ovulation and anovulatory PCOS patients. OBJECTIVE Our objective was to study differences in clinical and endocrine characteristics and response to ovulation induction (OI) treatment comparing oligoovulatory and anovulatory PCOS patients. DESIGN AND SETTING We conducted a retrospective cohort study at a tertiary hospital. PATIENTS PCOS patients (n=1750) presenting with oligo- or amenorrhea were diagnosed according to the Rotterdam 2003 consensus criteria. Arbitrarily, oligoovulatory PCOS was defined by a single random serum progesterone level of 10 nmol/liter or higher. MAIN OUTCOME MEASURES We evaluated the incidence of oligo- or amenorrhea, menstrual cycle length, serum androgen levels, follicle count, and OI outcome parameters. RESULTS Anovulatory women (n=1541 of 1750, 88.1%) were more often amenorrheic (P<0.001) and presented with a longer cycle duration (P<0.001) compared with oligoovulatory women (n=209 of 1750, 11.9%). Serum levels of testosterone (P<0.001), the free androgen index (P<0.001), and total follicle count (P<0.005) were higher in anovulatory compared with oligoovulatory patients. During clomiphene citrate OI, more oligoovulatory women gained regular menstrual cycles (P<0.05), whereas after second-line treatment with recombinant FSH, more anovulatory women became pregnant (P<0.05). CONCLUSIONS Oligoovulatory women with PCOS exhibit a milder phenotype of ovarian dysfunction and have a more favorable response to OI treatment using clomiphene citrate compared with anovulatory PCOS patients. However, during second-line treatment with recombinant FSH, anovulatory PCOS patients presented with a higher chance of pregnancy compared with oligoovulatory patients.


Human Reproduction | 2011

Genetic polymorphisms of the glucocorticoid receptor may affect the phenotype of women with anovulatory polycystic ovary syndrome

O. Valkenburg; André G. Uitterlinden; Axel P. N. Themmen; F.H. de Jong; A. Hofman; B.C.J.M. Fauser; Joop S.E. Laven

BACKGROUND Polycystic ovary syndrome (PCOS) is characterized by ovarian dysfunction. The association with obesity and insulin resistance is well established. Steroid hormones play a central role in the regulation of both ovarian function and body composition. This study aims to assess the influence of known functional polymorphisms in genes that are responsible for the production, metabolism and signal transduction of steroid hormones on the susceptibility to and phenotype of PCOS. METHODS We included 518 Caucasian women with anovulatory PCOS (2003 Rotterdam criteria) and 2996 population-based controls. Functional polymorphic variants were selected in genes that affect the production of estradiol and cortisol [aromatase (CYP19), 11-beta-hydroxysteroid dehydrogenase type I (HSD11B1) and hexose-6-phosphate dehydogenase (H6PD)] and in genes for signal transduction proteins [estrogen receptor (ESR1 and ESR2) and glucocorticoid receptor (GCR)]. RESULTS Genotype-frequencies were similar in PCOS cases and population-based controls. We observed possible associations between GCR genotype and LH levels that suggest an inhibitory influence of GCR, i.e., lower LH levels in association with GCR alleles that are known to increase receptor sensitivity (rs6195 and rs41423247) and higher LH levels in GCR variants that may inhibit receptor sensitivity (rs6190 and rs6198). CONCLUSIONS The present study did not identify risk alleles for PCOS, although the study was limited by an absence of endocrine data for the population-based controls. However, GCR variants may influence gonadotrophin levels in women with anovulatory PCOS. We hypothesize that glucocorticoids can affect the function of the hypothalomo-pituitary-gonadal axis in humans.


Fertility and Sterility | 2015

Follicle-stimulating hormone receptor polymorphism affects the outcome of ovulation induction in normogonadotropic (World Health Organization class 2) anovulatory subfertility

O. Valkenburg; Evert J. P. van Santbrink; Tamar E. König; Axel P. N. Themmen; André G. Uitterlinden; Bart C.J.M. Fauser; Cornelis B. Lambalk; Joop S.E. Laven

OBJECTIVE To assess whether an FSH receptor polymorphism (Asn680Ser, rs6166) can affect the outcome of ovulation induction in normogonadotropic (World Health Organization class 2 [WHO2]) anovulatory subfertile women. DESIGN Prospective, longitudinal, cohort study. SETTING University-based fertility unit. PATIENT(S) A total of 240 consecutive women diagnosed with WHO2 anovulatory subfertility who underwent ovulation induction therapy. Results were replicated in a retrospective cohort of 185 patients with polycystic ovary syndrome (PCOS) (Rotterdam criteria). INTERVENTION(S) Ovulation induction using clomiphene citrate (CC) as first-line and exogenous gonadotropins (exFSH) as second-line therapy. MAIN OUTCOME MEASURE(S) Clomiphene-resistant anovulation (CRA), clomiphene failure (CCF), and ongoing pregnancy rate. RESULT(S) Genotyped patients (n = 159) were similar to nongenotyped women (n = 81) regarding clinical characteristics and outcomes of ovulation induction. The 680(Ser) allele was associated with CRA. A pooled analysis of both cohorts showed an 89% higher chance of CRA after CC treatment (odds ratio 1.9 [95% confidence interval 1.1-3.3]) in homozygous carriers of the FSH receptor variant (680(Ser/Ser)). A lower chance of ongoing pregnancy (hazard ratio 0.51 [95% confidence interval 0.27-0.98]) was observed among these patients during CC treatment in the prospective cohort. CONCLUSION(S) An FSH receptor polymorphism is associated with CRA during treatment with clomiphene citrate. These data may be used to design a treatment algorithm that is more efficacious and better tailored to the individual patient.


The Journal of Clinical Endocrinology and Metabolism | 2011

Genetic Ancestry Affects the Phenotype of Normogonadotropic Anovulatory (WHOII) Subfertility

O. Valkenburg; O. Lao; I. Schipper; Yvonne V. Louwers; A.G. Uitterlinden; Manfred Kayser; Joop S.E. Laven

INTRODUCTION Normogonadotropic (World Health Organization category II) anovulation is the most frequent cause of reduced fertility. Anovulation is associated with endocrine changes, i.e. hyperandrogenism, obesity, and insulin resistance. However, the phenotype is notoriously heterogeneous, depending on population characteristics and diagnostic criteria. OBJECTIVE Our objective was to study the phenotype of normogonadotropic anovulatory women among various ethnic subgroups that coexist in an urban community (The Netherlands). Moreover, we studied whether genetic ancestry testing can be used to identify bio-geographic ancestry and predict the phenotype of individual patients. MATERIALS AND METHODS A standardized clinical and endocrine examination was performed in 1517 normogonadotropic anovulatory women. Bio-geographic ancestry was ascertained by questionnaire and genetic testing (637 cases), using a set of 10 previously validated ancestry informative markers. RESULTS Subgroups constituted individuals from northwestern European (n = 774), Mediterranean European (north of Sahara and Middle East, n = 220), African (n = 111), Southeast Asian (n = 53), and Hindustani (n = 83) origin. Phenotypic differences included fasting insulin levels, androgen levels, and the frequency of hyperandrogenism (ranging from 76% in Mediterranean-European women to 41% in northwestern European women). Genetic ancestry testing was able to identify population structure on a continental level, i.e. European, African and Southeast Asian descent. We did not observe improved informativeness when genotype data were added to the prediction model. CONCLUSION Population differences add to the phenotype of normogonadotropic anovulation and need to be taken into account when evaluating the individual patient. Although effective on a continental level, the present set of ancestry markers was not sufficiently effective to describe all ethnic variation in the phenotype of anovulatory subfertility.

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Joop S.E. Laven

Erasmus University Rotterdam

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Frank H. de Jong

Erasmus University Rotterdam

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Yvonne V. Louwers

Erasmus University Rotterdam

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Axel P. N. Themmen

Erasmus University Rotterdam

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Jenny A. Visser

Erasmus University Rotterdam

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Sharon Lie Fong

Erasmus University Rotterdam

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B.C.J.M. Fauser

Erasmus University Rotterdam

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