R P Stolk

University of Groningen, Groningen, Groningen, Netherlands

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Publications (141)708.33 Total impact

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    ABSTRACT: Background: Exposure to ambient air pollution may be associated with impaired mental health, including depression. However, evidence originates mainly from animal studies and epidemiological studies in specific subgroups. We investigated the association between air pollution and depressed mood in four European general population cohorts. Methods: Data were obtained from LifeLines (the Netherlands), KORA (Germany), HUNT (Norway), and FINRISK (Finland). Residential exposure to particles (PM2.5, PM2.5absorbance, PM10) and nitrogen dioxide (NO2) was estimated using land use regression (LUR) models developed for the European Study of Cohorts for Air Pollution Effects (ESCAPE) and using European wide LUR models. Depressed mood was assessed with interviews and questionnaires. Logistic regression analyses were used to investigate the cohort specific associations between air pollution and depressed mood. Results: A total of 70,928 participants were included in our analyses. Depressed mood ranged from 1.6% (KORA) to 11.3% (FINRISK). Cohort specific associations of the air pollutants and depressed mood showed heterogeneous results. For example, positive associations were found for NO2 in LifeLines (odds ratio [OR]=1.34; 95% CI: 1.17, 1.53 per 10μg/m(3) increase in NO2), whereas negative associations were found in HUNT (OR=0.79; 95% CI: 0.66, 0.94 per 10μg/m(3) increase in NO2). Conclusions: Our analyses of four European general population cohorts found no consistent evidence for an association between ambient air pollution and depressed mood.
    Full-text · Article · Dec 2015 · International journal of hygiene and environmental health
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    ABSTRACT: We investigated the role of a stress-sensitive personality on relations between noise, noise annoyance and somatic symptom reporting. First, we investigated the cross-sectional association of road traffic noise exposure and somatic symptoms, and its modification by hostility and vulnerability to stress. Second, we investigated the cross-sectional association of noise annoyance from eight sources (e.g. road traffic, aircraft, neighbours) and somatic symptoms, and it's confounding by hostility and vulnerability to stress. Data were obtained from LifeLines, a general population cohort from the Netherlands. Road traffic noise was estimated using the Common Noise Assessment Methods in Europe (CNOSSOS-EU) noise model. Noise annoyance, hostility, vulnerability to stress, and somatic symptoms were assessed with validated questionnaires. Poisson regression models adjusted for demographic and socioeconomic variables indicated no association of noise exposure and somatic symptoms (incidence rate ratio (IRR) 1.001; 95% confidence interval (CI) 1.000-1.001; n=56,937). Interactions of noise exposure and hostility and vulnerability to stress were not statistically significant. Small positive associations were found for noise annoyance from each of the eight sources and somatic symptoms, when adjusted for demographic and socioeconomic variables (e.g. for road traffic noise annoyance IRR 1.014, 95% CI 1.011-1.018; n=6177). Additional adjustment for hostility and vulnerability to stress resulted in small decreases of the IRRs for noise annoyance from each of the eight sources, but the associations remained statistically significant. Personality facets hostility and vulnerability to stress did not modify the relation between road traffic noise exposure and somatic symptom reporting, or confound relations between noise annoyance and symptoms. Copyright © 2015 Elsevier GmbH. All rights reserved.
    Full-text · Article · May 2015 · International journal of hygiene and environmental health
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    ABSTRACT: Obesity tracks from childhood into adulthood. We evaluated the effect of early stimulation of physical activity on growth, body composition, motor activity and motor development in toddlers. We performed a cluster randomised controlled single-blinded trial in Dutch Well Baby Clinics, with seven nurses and 96 children (40% girls) randomised to the intervention group and six nurses and 65 children (57% girls) to the control group. Intervention nurses advised parents on stimulating motor development and physical activity during regular visits at two weeks and two, four, eight and 11 months. Baseline characteristics like birth weight and mode of feeding were comparable. Outcomes at two-and-a-half years included anthropometry, skinfold thicknesses, bioelectrical impedance analyses, motor development and daily physical activity. We used linear mixed models with nurses as cluster. We evaluated 143 children (89 intervention, 54 control) as 18 dropped out. Skinfolds were significantly lower in intervention children (29.6±4.7mm) than controls (32.4±6.0mm), without differences in motor development or daily physical activity. Female interventions showed lower weight, skinfolds, waist and hip circumference. An activity stimulating programme during the child's first year improved indicators of adiposity when they were toddlers, especially in girls. Further research should determine if these effects persist. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.
    No preview · Article · Nov 2014 · Acta paediatrica (Oslo, Norway: 1992). Supplement
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    ABSTRACT: Coffee, a major dietary source of caffeine, is among the most widely consumed beverages in the world and has received considerable attention regarding health risks and benefits. We conducted a genome-wide (GW) meta-analysis of predominately regular-type coffee consumption (cups per day) among up to 91 462 coffee consumers of European ancestry with top single-nucleotide polymorphisms (SNPs) followed-up in ~30 062 and 7964 coffee consumers of European and African-American ancestry, respectively. Studies from both stages were combined in a trans-ethnic meta-analysis. Confirmed loci were examined for putative functional and biological relevance. Eight loci, including six novel loci, met GW significance (log10Bayes factor (BF)>5.64) with per-allele effect sizes of 0.03-0.14 cups per day. Six are located in or near genes potentially involved in pharmacokinetics (ABCG2, AHR, POR and CYP1A2) and pharmacodynamics (BDNF and SLC6A4) of caffeine. Two map to GCKR and MLXIPL genes related to metabolic traits but lacking known roles in coffee consumption. Enhancer and promoter histone marks populate the regions of many confirmed loci and several potential regulatory SNPs are highly correlated with the lead SNP of each. SNP alleles near GCKR, MLXIPL, BDNF and CYP1A2 that were associated with higher coffee consumption have previously been associated with smoking initiation, higher adiposity and fasting insulin and glucose but lower blood pressure and favorable lipid, inflammatory and liver enzyme profiles (P<5 × 10(-8)).Our genetic findings among European and African-American adults reinforce the role of caffeine in mediating habitual coffee consumption and may point to molecular mechanisms underlying inter-individual variability in pharmacological and health effects of coffee.Molecular Psychiatry advance online publication, 7 October 2014; doi:10.1038/mp.2014.107.
    Full-text · Article · Oct 2014 · Molecular Psychiatry
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    ABSTRACT: Background In the Action in Diabetes and Vascular Disease: Preterax and Diamicron Modified Release Controlled Evaluation (ADVANCE) factorial trial, the combination of perindopril and indapamide reduced mortality among patients with type 2 diabetes, but intensive glucose control, targeting a glycated hemoglobin level of less than 6.5%, did not. We now report results of the 6-year post-trial follow-up. Methods We invited surviving participants, who had previously been assigned to perindopril-indapamide or placebo and to intensive or standard glucose control (with the glucose-control comparison extending for an additional 6 months), to participate in a post-trial follow-up evaluation. The primary end points were death from any cause and major macrovascular events. Results The baseline characteristics were similar among the 11,140 patients who originally underwent randomization and the 8494 patients who participated in the post-trial follow-up for a median of 5.9 years (blood-pressure-lowering comparison) or 5.4 years (glucose-control comparison). Between-group differences in blood pressure and glycated hemoglobin levels during the trial were no longer evident by the first post-trial visit. The reductions in the risk of death from any cause and of death from cardiovascular causes that had been observed in the group receiving active blood-pressure-lowering treatment during the trial were attenuated but significant at the end of the post-trial follow-up; the hazard ratios were 0.91 (95% confidence interval [CI], 0.84 to 0.99; P=0.03) and 0.88 (95% CI, 0.77 to 0.99; P=0.04), respectively. No differences were observed during follow-up in the risk of death from any cause or major macrovascular events between the intensive-glucose-control group and the standard-glucose-control group; the hazard ratios were 1.00 (95% CI, 0.92 to 1.08) and 1.00 (95% CI, 0.92 to 1.08), respectively. Conclusions The benefits with respect to mortality that had been observed among patients originally assigned to blood-pressure-lowering therapy were attenuated but still evident at the end of follow-up. There was no evidence that intensive glucose control during the trial led to long-term benefits with respect to mortality or macrovascular events. (Funded by the National Health and Medical Research Council of Australia and others; ADVANCE-ON ClinicalTrials.gov number, NCT00949286 .).
    Full-text · Article · Sep 2014 · New England Journal of Medicine
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    ABSTRACT: Aim: Up to 18.1% of Dutch children aged 3-5 are overweight and up to 3.3% are obese, with higher levels in girls. This study assessed the effect of a multidisciplinary intervention programme on health-related quality of life (HRQoL) in this patient group. Methods: We randomised 75 children to a multidisciplinary intervention, comprising dietary advice, exercise sessions and psychological counselling for parents or the standard care programme, providing healthy lifestyle advice. The parents completed quality of life and child health questionnaires at baseline and after 16 weeks and 12 months. Results: At 16 weeks, children in the intervention group experienced more bodily pain and less mental health than the standard care group, but at 12 months, this difference disappeared and they showed a more positive change in HRQoL than the standard care group, especially for the physical domain. When we combined both groups, a decreased BMIz-score over 12 months was associated with increased global health and reduced visceral fat correlated with increased general health. Conclusion: At 12 months, a multidisciplinary intervention programme for overweight and obese children aged 3-5 years had beneficial effects on HRQoL, especially for the physical domain. Reduced obesity parameters correlated with several increased HRQoL parameters.
    No preview · Article · May 2014 · Acta paediatrica (Oslo, Norway: 1992). Supplement
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    ABSTRACT: The purpose of this longitudinal observational study was to (i) examine the change of daily physical activity in 28 adult kidney transplant recipients over the first 12 months following transplantation; and (ii) to examine the change in metabolic characteristics and renal function. Accelerometer-based daily physical activity and metabolic- and clinical characteristics were measured at six wk (T1), three months (T2), six months (T3) and 12 months (T4) following transplantation. Linear mixed effect analyses showed an increase in steps/d (T1 = 6326 ± 2906; T4 = 7562 ± 3785; F = 3.52; p = 0.02), but one yr after transplantation only 25% achieved the recommended 10 000 steps/d. There was no significant increase in minutes per day spent on moderate-to-vigorous intensity physical activity (T1 = 80.4 ± 63.6; T4 = 93.2 ± 55.1; F = 1.71; p = 0.17). Body mass index increased over time (T1 = 25.4 ± 3.2; T4 = 27.2 ± 3.8; F = 12.62; p < 0.001), mainly due to an increase in fat percentage (T1 = 30.3 ± 8.0; T4 = 34.0 ± 7.9; F = 14.63; p < 0.001). There was no significant change in renal function (F = 0.17; p = 0.92). Although the recipients increased physical activity, the majority did not meet the recommended levels of physical activity after one yr. In addition to the weight gain, this may result in negative health consequences. Therefore, it is important to develop strategies to support kidney transplant recipients to comply with healthy lifestyle recommendations, including regular physical activity.
    No preview · Article · Mar 2014 · Clinical Transplantation
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    ABSTRACT: Low plasma 25-hydroxyvitamin D (25[OH]D) concentration is associated with high arterial blood pressure and hypertension risk, but whether this association is causal is unknown. We used a mendelian randomisation approach to test whether 25(OH)D concentration is causally associated with blood pressure and hypertension risk. METHODS In this mendelian randomisation study, we generated an allele score (25[OH]D synthesis score) based on variants of genes that affect 25(OH)D synthesis or substrate availability (CYP2R1 and DHCR7), which we used as a proxy for 25(OH)D concentration. We meta-analysed data for up to 108 173 individuals from 35 studies in the D-CarDia collaboration to investigate associations between the allele score and blood pressure measurements. We complemented these analyses with previously published summary statistics from the International Consortium on Blood Pressure (ICBP), the Cohorts for Heart and Aging Research in Genomic Epidemiology (CHARGE) consortium, and the Global Blood Pressure Genetics (Global BPGen) consortium. FINDINGS In phenotypic analyses (up to n=49 363), increased 25(OH)D concentration was associated with decreased systolic blood pressure (β per 10% increase, -0·12 mm Hg, 95% CI -0·20 to -0·04; p=0·003) and reduced odds of hypertension (odds ratio [OR] 0·98, 95% CI 0·97-0·99; p=0·0003), but not with decreased diastolic blood pressure (β per 10% increase, -0·02 mm Hg, -0·08 to 0·03; p=0·37). In meta-analyses in which we combined data from D-CarDia and the ICBP (n=146 581, after exclusion of overlapping studies), each 25(OH)D-increasing allele of the synthesis score was associated with a change of -0·10 mm Hg in systolic blood pressure (-0·21 to -0·0001; p=0·0498) and a change of -0·08 mm Hg in diastolic blood pressure (-0·15 to -0·02; p=0·01). When D-CarDia and consortia data for hypertension were meta-analysed together (n=142 255), the synthesis score was associated with a reduced odds of hypertension (OR per allele, 0·98, 0·96-0·99; p=0·001). In instrumental variable analysis, each 10% increase in genetically instrumented 25(OH)D concentration was associated with a change of -0·29 mm Hg in diastolic blood pressure (-0·52 to -0·07; p=0·01), a change of -0·37 mm Hg in systolic blood pressure (-0·73 to 0·003; p=0·052), and an 8·1% decreased odds of hypertension (OR 0·92, 0·87-0·97; p=0·002). INTERPRETATION Increased plasma concentrations of 25(OH)D might reduce the risk of hypertension. This finding warrants further investigation in an independent, similarly powered study. FUNDING British Heart Foundation, UK Medical Research Council, and Academy of Finland.
    Full-text · Article · Jan 2014 · The Lancet Diabetes & Endocrinology
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    ABSTRACT: Skipping breakfast is associated with higher BMI in children aged 5 years and older. However, not much is known about this association in younger children. In the Dutch GECKO Drenthe birth cohort we examined the association between breakfast skipping and objectively measured overweight at the age of 2 (n=1488) and 5 (n=1366) years old. At 2 years 124 (8.3%) children were overweight and 44 (3.0%) did not eat breakfast daily. At 5 years 180 (13.2%) children were overweight and 73 (5.3%) did not eat breakfast daily. Children skipped breakfast more often in families of non-Dutch origin, lower educated parents and single-parents. Breakfast skipping in 2 and 5 year-olds is rare in the Netherlands. We found no association between skipping breakfast and overweight, neither at age 2 (OR: 1.85 (95% CI: 0.61-5.64)) nor at age 5 (OR: 0.46 (95% CI: 0.19-1.11)). Also the type of breakfast was not related to overweight at 5 years, an explanation for this finding might be that skipping breakfast is not (yet) an issue in these children.International Journal of Obesity accepted article preview online, 25 October 2013; doi:10.1038/ijo.2013.194.
    No preview · Article · Oct 2013 · International journal of obesity (2005)
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    ABSTRACT: Background: Although physical activity is beneficial for Parkinson's disease (PD) patients, many do not meet the recommended levels. The range of physical activity among sedentary PD patients is unknown, as are factors that determine this variability. Hence, we aimed to (1) assess daily physical activity in self-identified sedentary PD patients; (2) compare this with criteria of a daily physical activity guideline; and (3) identify determinants of daily physical activity. Methods: Daily physical activity of 586 self-identified sedentary PD patients was measured with a tri-axial accelerometer for seven consecutive days. Physical fitness and demographic, disease-specific, and psychological characteristics were assessed. Daily physical activity was compared with the 30-min activity guideline. A linear mixed-effects model was estimated to identify determinants of daily physical activity. Results: Accelerometer data of 467 patients who fulfilled all criteria revealed that >98% of their day was spent on sedentary to light-intensity activities. Eighty-two percent of the participants were 'physically inactive' (0 days/week of 30-min activity); 17% were 'semi-active' (1-4 days/week of 30-min activity). Age, gender, physical fitness, and scores on the Unified Parkinson's Disease Rating Scale explained 69% of the variability in daily physical activity. Conclusions: Performance-based measurements confirmed that most self-identified sedentary PD patients are 'physically inactive'. However, the variance in daily physical activity across subjects was considerable. Higher age, being female, and lower physical capacity were the most important determinants of reduced daily physical activity. Future therapeutic interventions should aim to improve daily physical activity in these high-risk patients, focusing specifically on modifiable risk factors.
    No preview · Article · Jun 2013 · Parkinsonism & Related Disorders
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    ABSTRACT: Elevated resting heart rate is associated with greater risk of cardiovascular disease and mortality. In a 2-stage meta-analysis of genome-wide association studies in up to 181,171 individuals, we identified 14 new loci associated with heart rate and confirmed associations with all 7 previously established loci. Experimental downregulation of gene expression in Drosophila melanogaster and Danio rerio identified 20 genes at 11 loci that are relevant for heart rate regulation and highlight a role for genes involved in signal transmission, embryonic cardiac development and the pathophysiology of dilated cardiomyopathy, congenital heart failure and/or sudden cardiac death. In addition, genetic susceptibility to increased heart rate is associated with altered cardiac conduction and reduced risk of sick sinus syndrome, and both heart rate–increasing and heart rate–decreasing variants associate with risk of atrial fibrillation. Our findings provide fresh insights into the mechanisms regulating heart rate and identify new therapeutic targets.
    Full-text · Article · Apr 2013 · Nature Genetics
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    ABSTRACT: Elevated resting heart rate is associated with greater risk of cardiovascular disease and mortality. In a 2-stage meta-analysis of genome-wide association studies in up to 181,171 individuals, we identified 14 new loci associated with heart rate and confirmed associations with all 7 previously established loci. Experimental downregulation of gene expression in Drosophila melanogaster and Danio rerio identified 20 genes at 11 loci that are relevant for heart rate regulation and highlight a role for genes involved in signal transmission, embryonic cardiac development and the pathophysiology of dilated cardiomyopathy, congenital heart failure and/or sudden cardiac death. In addition, genetic susceptibility to increased heart rate is associated with altered cardiac conduction and reduced risk of sick sinus syndrome, and both heart rate-increasing and heart rate-decreasing variants associate with risk of atrial fibrillation. Our findings provide fresh insights into the mechanisms regulating heart rate and identify new therapeutic targets.
    Full-text · Article · Apr 2013 · Nature Genetics
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    ABSTRACT: Elevated resting heart rate is associated with greater risk of cardiovascular disease and mortality. In a 2-stage meta-analysis of genome-wide association studies in up to 181,171 individuals, we identified 14 new loci associated with heart rate and confirmed associations with all 7 previously established loci. Experimental downregulation of gene expression in Drosophila melanogaster and Danio rerio identified 20 genes at 11 loci that are relevant for heart rate regulation and highlight a role for genes involved in signal transmission, embryonic cardiac development and the pathophysiology of dilated cardiomyopathy, congenital heart failure and/or sudden cardiac death. In addition, genetic susceptibility to increased heart rate is associated with altered cardiac conduction and reduced risk of sick sinus syndrome, and both heart rate–increasing and heart rate–decreasing variants associate with risk of atrial fibrillation. Our findings provide fresh insights into the mechanisms regulating heart rate and identify new therapeutic targets.
    Full-text · Article · Apr 2013 · Nature Genetics

  • No preview · Article · Dec 2012 · Journal of Science and Medicine in Sport

  • No preview · Article · Dec 2012 · Journal of Science and Medicine in Sport
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    ABSTRACT: Objectives: Glycated haemoglobin (HbA1c) is associated with cardiovascular disease risk in individuals without diabetes, and its use has been recommended for diagnosing diabetes. Therefore, it is important to gain further understanding of the determinants of HbA1c. The aim of this study was to investigate the effects of genetic loci and clinical and lifestyle parameters, and their interactions, on HbA1c in nondiabetic adults. Design: Population-based cohort study. Setting: Three northern provinces of the Netherlands. Subjects: A total of 2921 nondiabetic adults participating in the population-based LifeLines Cohort Study. Measurements: Body mass index (BMI), waist circumference, HbA1c, fasting plasma glucose (FPG) and erythrocyte indices were measured. Data on current smoking and alcohol consumption were collected through questionnaires. Genome-wide genotyping was performed, and 12 previously identified single-nucleotide polymorphisms (SNPs) were selected for replication and categorized as 'glycaemic' and 'nonglycaemic' SNPs according to their presumed mechanism(s) of action on HbA1c. Genetic risk scores (GRSs) were calculated as the sum of the weighted effect of HbA1c-increasing alleles. Results: Age, gender, BMI, FPG, mean corpuscular haemoglobin, mean corpuscular haemoglobin concentration, current smoking and alcohol consumption were independent predictors of HbA1c, together explaining 26.2% of the variance in HbA1c, with FPG contributing 10.9%. We replicated three of the previously identified SNPs and the GRSs were also found to be independently associated with HbA1c. We found a smaller effect of the 'nonglycaemic GRS' in females compared with males and an attenuation of the effect of the GRS of all 12 SNPs with increasing BMI. Conclusions: Our results suggest that a substantial portion of HbA1c is determined by nonglycaemic factors. This should be taken into account when considering the use of HbA1c as a diagnostic test for diabetes.
    No preview · Article · Nov 2012 · Journal of Internal Medicine
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    ABSTRACT: Vasopressin plays a role in osmoregulation, glucose homeostasis and inflammation. Therefore, plasma copeptin, the stable C-terminal portion of the precursor of vasopressin, has strong potential as a biomarker for the cardiometabolic syndrome and diabetes. Previous results were contradictory, which may be explained by differences between men and women in responsiveness of the vasopressin system. The aim of this study was to evaluate the usefulness of copeptin for prediction of future type 2 diabetes in men and women separately. From the Prevention of Renal and Vascular Endstage Disease (PREVEND) study, 4,063 women and 3,909 men without diabetes at baseline were included. A total of 208 women and 288 men developed diabetes during a median follow-up of 7.7 years. In multivariable-adjusted models, we observed a stronger association of copeptin with risk of future diabetes in women (OR 1.49 [95% CI 1.24, 1.79]) than in men (OR 1.01 [95% CI 0.85, 1.19]) (p (interaction) < 0.01). The addition of copeptin to the Data from the Epidemiological Study on the Insulin Resistance Syndrome (DESIR) clinical model improved the discriminative value (C-statistic,+0.007, p = 0.02) and reclassification (integrated discrimination improvement [IDI] = 0.004, p < 0.01) in women. However, we observed no improvement in men. The additive value of copeptin in women was maintained when other independent predictors, such as glucose, high sensitivity C-reactive protein (hs-CRP) and 24 h urinary albumin excretion (UAE), were included in the model. The association of plasma copeptin with the risk of developing diabetes was stronger in women than in men. Plasma copeptin alone, and along with existing biomarkers (glucose, hs-CRP and UAE), significantly improved the risk prediction for diabetes in women.
    Full-text · Article · Apr 2012 · Diabetologia
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    ABSTRACT: Acknowledgements: BBMRI-NL is a Research Infrastructure financed by the Dutch government (NWO 184.021.007). Competing interests: Professor van Ommen is scientific director; Dr. Brandsma is program manager at BBMRI-NL.
    Full-text · Article · Jan 2012 · Norsk Epidemiologi
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    ABSTRACT: : To newly identify loci for age at natural menopause, we carried out a meta-analysis of 22 genome-wide association studies (GWAS) in 38,968 women of European descent, with replication in up to 14,435 women. In addition to four known loci, we identified 13 loci newly associated with age at natural menopause (at P < 5 × 10(-8)). Candidate genes located at these newly associated loci include genes implicated in DNA repair (EXO1, HELQ, UIMC1, FAM175A, FANCI, TLK1, POLG and PRIM1) and immune function (IL11, NLRP11 and PRRC2A (also known as BAT2)). Gene-set enrichment pathway analyses using the full GWAS data set identified exoDNase, NF-?B signaling and mitochondrial dysfunction as biological processes related to timing of menopause.
    Full-text · Article · Jan 2012 · Nature Genetics
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    ABSTRACT: Both maternal and paternal factors have been suggested to influence a couple's fecundity. To investigate this, we examined the role of several maternal and paternal lifestyle and socio-demographic factors as determinants of time to pregnancy (TTP) in a Dutch birth-cohort. Groningen Expert Center for Kids with Obesity (GECKO) Drenthe is a population-based birth-cohort study of children born between April 2006 and April 2007 in Drenthe, a province of The Netherlands. Both partners received extensive questionnaires during pregnancy. Univariable and multivariable Cox regression analyses were used to determine the impact of the investigated factors on TTP. A total of 4778 children were born, and the parents of 2997 children (63%) gave their consent to participate. After excluding unintended pregnancies and pregnancies as a result of fertility treatment, the data of 1924 couples were available for analysis. Hazards ratios and 95% confidence intervals of factors influencing TTP in multivariable Cox regression analysis were: maternal age 1.23 (0.98-1.54) for age <25 years, 1.17 (1.03-1.32) for age 25-30 years and 0.72 (0.61-0.85) for age >35 years (reference category: 30-35 years); paternal age: 1.31 (0.94-1.82) for age <25 years, 1.11 (0.97-1.28) for age 25-30 years and 0.91 (0.80-1.04 for age >35 years (reference category: 30-35 years); nulliparity: 0.76 (0.68-0.85) versus multiparity; menstrual cycle length: 1.12 (0.95-1.30) for 3 weeks, 0.72 (0.62-0.83) for 4-6 weeks, 0.68 (0.40-1.16) for >6 weeks and 0.66 (0.54-0.81) for irregular cycle (reference category: 4 weeks); prior contraceptive use: 0.78 (0.67-0.91) for no contraception, 1.68 (1.45-1.95) for condom use, 1.08 (0.89-1.33) for condom use combined with oral contraception, 1.40 (1.16-1.70) for intrauterine device and 0.50 (0.25-1.01) for contraceptive injection (reference category: oral contraception); and maternal educational level 0.75 (0.62-0.92) for low education level and 0.81 (0.73-0.90) for medium educational level (reference category: high educational level). This population-based birth-cohort study performed in fertile couples who had conceived revealed neither maternal nor paternal modifiable lifestyle factors were significantly associated with TTP after adjustment for confounding by socio-demographic factors. In contrast, several non-modifiable maternal socio-demographic factors are significant predictors of a couple's fecundity.
    Full-text · Article · Dec 2011 · Human Reproduction

Publication Stats

6k Citations
708.33 Total Impact Points

Institutions

  • 2007-2015
    • University of Groningen
      • Department of Epidemiology
      Groningen, Groningen, Netherlands
  • 2007-2012
    • Universitair Medisch Centrum Groningen
      Groningen, Groningen, Netherlands
  • 1999-2012
    • Leiden University Medical Centre
      • • Department of Human Genetics
      • • Department of Molecular Cell Biology
      Leyden, South Holland, Netherlands
  • 2006
    • University of Sydney
      • George Institute for Global Health
      Sydney, New South Wales, Australia
  • 1998-2005
    • University Medical Center Utrecht
      • • Julius Center for Health Sciences and Primary Care
      • • Department of Radiology
      Utrecht, Utrecht, Netherlands
  • 2002-2004
    • University of Pretoria
      • • Department of Clinical Epidemiology
      • • Department of Internal Medicine
      Πρετόρια/Πόλη του Ακρωτηρίου, Gauteng, South Africa
  • 1998-2004
    • Utrecht University
      • • Division of Pharmacoepidemiology and Pharmacotherapy
      • • Department of General Practice
      Utrecht, Utrecht, Netherlands
  • 1993-1998
    • Erasmus Universiteit Rotterdam
      • Department of Internal Medicine
      Rotterdam, South Holland, Netherlands
  • 1996
    • Leiden University
      Leyden, South Holland, Netherlands