Reini W Bretveld

Publications of Reini W Bretveld

• Estrogenic and androgenic activities in total plasma measured with reporter-gene bioassays: relevant exposure measures for endocrine disruptors in epidemiologic studies?

  Authors: Marijn M Brouwers, Harrie Besselink, Reini W Bretveld, Rob Anzion, Paul T J Scheepers, Abraham Brouwer, Nel Roeleveld

  Environment international. 04/2011; 37(3):557-64.

  Measurements of estrogenic and androgenic activities in total plasma with Chemically Activated LUciferase gene eXpression (CALUX®) bioassays could provide biologically relevant measures for exposureMeasurements of estrogenic and androgenic activities in total plasma with Chemically Activated LUciferase gene eXpression (CALUX®) bioassays could provide biologically relevant measures for exposure to endocrine disruptors in epidemiologic studies. The objective of this study was to explore the effects of a variety of sources of potential endocrine disruptors on estrogenic and androgenic activities in total plasma measured by CALUX®. Plasma samples and interview data on sources of potential endocrine disruptors were collected from 108 men with different exposures profiles. CALUX® measurements (BioDetection Services) involved human U2-OS cell lines controlled by the estrogen receptor alpha and the androgen receptor. Mean differences (beta) in 17β-estradiol equivalents (EEQs) and dihydrotestosterone equivalents (AEQs) between exposure groups were estimated using general linear models. Mean plasma AEQs and EEQs were 9.1×10(-1)ng/ml and 12.0pg/ml, respectively. Elevated AEQs were found in smokers (beta 1.9 (95%CI 0.1-3.6)×10(-1)ng/ml) and heavy drinkers (1.4 (0.2-3.1)×10(-1)ng/ml), and in men occupationally exposed to disinfectants (1.6 (0.3-3.5)×10(-1)ng/ml) or welding/soldering fumes (1.4 (-0.2-2.9)×10(-1)ng/ml). Occupational exposure to pesticides, disinfectants, and exhaust fumes seemed to be associated with increased plasma EEQs: 1.5 (-0.2-3.2)pg/ml, 2.1 (0.2-3.9)pg/ml, and 2.9 (0.6-5.2)pg/ml, respectively. Moderate to high plasma dioxin levels, measured in a subgroup by the dioxin-responsive CALUX®, were accompanied by a 20% increase in AEQs. This is the first study in which CALUX® was used to assess hormone activities in total plasma. Although the results are not yet readily interpretable, they indicate that these measurements can be valuable for epidemiologic studies on endocrine disruptors and give direction for further research.

• Reporting on the modes of data collection.

  Authors: Marleen M H J van Gelder, Reini W Bretveld, Nel Roeleveld

  Lancet. 01/2011; 377(9759):30.

• Web-based questionnaires: the future in epidemiology?

  Authors: Marleen M H J van Gelder, Reini W Bretveld, Nel Roeleveld

  American journal of epidemiology. 09/2010; 172(11):1292-8.

  The traditional epidemiologic modes of data collection, including paper-and-pencil questionnaires and interviews, have several limitations, such as decreasing response rates over the last decades andThe traditional epidemiologic modes of data collection, including paper-and-pencil questionnaires and interviews, have several limitations, such as decreasing response rates over the last decades and high costs in large study populations. The use of Web-based questionnaires may be an attractive alternative but is still scarce in epidemiologic research because of major concerns about selective nonresponse and reliability of the data obtained. The authors discuss advantages and disadvantages of Web-based questionnaires and current developments in this area. In addition, they focus on some practical issues and safety concerns involved in the application of Web-based questionnaires in epidemiologic research. They conclude that many problems related to the use of Web-based questionnaires have been solved or will most likely be solved in the near future and that this mode of data collection offers serious benefits. However, questionnaire design issues may have a major impact on response and completion rates and on reliability of the data. Theoretically, Web-based questionnaires could be considered an alternative or complementary mode in the range of epidemiologic methods of data collection. Practice and comparisons with the traditional survey techniques should reveal whether they can fulfill their expectations.

• Occupational exposure to potential endocrine disruptors: further development of a Job Exposure Matrix.

  Authors: Marijn M Brouwers, Martie van Tongeren, Adrian A Hirst, Reini W Bretveld, Nel Roeleveld

  Occupational and environmental medicine. 04/2009;

  OBJECTIVES: The aim was to develop a new up-to-date and comprehensive Job Exposure Matrix (JEM) for estimating exposure to potential endocrine disruptors in epidemiologic research. METHODS: ChemicalsOBJECTIVES: The aim was to develop a new up-to-date and comprehensive Job Exposure Matrix (JEM) for estimating exposure to potential endocrine disruptors in epidemiologic research. METHODS: Chemicals with endocrine disrupting properties were identified from the literature and classified into 10 chemical groups: polycyclic aromatic hydrocarbons (PAHs), polychlorinated organic compounds, pesticides, phthalates, organic solvents, bisphenol A, alkylphenolic compounds, brominated flame retardants, metals, and a miscellaneous group. Most chemical groups were divided into three to six subgroups. Focusing on the years 1996 - 2006, three experts scored the probability of exposure to each chemical group and subgroup for 353 job titles, in three levels: 'unlikely' (0), 'possible' (1), and 'probable' (2). Job titles with positive exposure probability scores were provided with exposure scenarios that described the reasoning behind the scores. RESULTS: For 238 job titles (67%), exposure to any chemical group was unlikely, whereas 102 (29%) job titles were classified as possibly (17%) or probably (12%) exposed to one or several endocrine disruptors. The remaining 13 job titles provided too little information to classify exposure. PAHs, pesticides, phthalates, organic solvents, alkylphenolic compounds, and metals were often linked to a job title in the JEM. The remaining chemical groups were found to involve very few occupations. CONCLUSIONS: Despite some important limitations, this JEM can be a valuable tool for exposure assessment in studies on health risks of endocrine disruptors, especially when task-specific information is incorporated. The documented exposure scenarios are meant to facilitate further adjustments to the JEM to allow more widespread use.

• Reproductive disorders among male and female greenhouse workers.

  Authors: Reini W Bretveld, Mariëtte Hooiveld, Gerhard A Zielhuis, Annelies Pellegrino, Iris A L M van Rooij, Nel Roeleveld

  Reproductive toxicology (Elmsford, N.Y.). 02/2008; 25(1):107-14.

  The aim of this study was to evaluate reproductive disorders in male and female greenhouse workers. In 2002, data were collected from 4872 Dutch greenhouse workers and 8133 referents through postalThe aim of this study was to evaluate reproductive disorders in male and female greenhouse workers. In 2002, data were collected from 4872 Dutch greenhouse workers and 8133 referents through postal questionnaires with detailed questions on reproductive disorders of the most recent pregnancy, lifestyle habits, and occupational exposures (e.g. pesticides) prior to conception. Different reproductive outcome measures were compared between 957 male and 101 female greenhouse workers and 1408 referents by means of logistic regression analyses. The analyses of primigravidous couples showed a slightly elevated risk of prolonged TTP (OR(women)=1.9; 95% CI: 0.8-4.4) and an increased risk of spontaneous abortion among female greenhouse workers (OR(women)=4.0; 95% CI: 1.1-14.0). A decreased risk of preterm birth was found among male greenhouse workers (OR(men)=0.1; 95% CI: 0.03-0.5). This study may offer some evidence for the hypothesis that pesticide exposure affects human reproduction leading to spontaneous abortion and possibly to prolonged time-to-pregnancy.

• Pesticide exposure: the hormonal function of the female reproductive system disrupted?

  Authors: Reini W Bretveld, Chris M G Thomas, Paul T J Scheepers, Gerhard A Zielhuis, Nel Roeleveld

  Reproductive biology and endocrinology : RB&E. 02/2006; 4:30.

  Some pesticides may interfere with the female hormonal function, which may lead to negative effects on the reproductive system through disruption of the hormonal balance necessary for properSome pesticides may interfere with the female hormonal function, which may lead to negative effects on the reproductive system through disruption of the hormonal balance necessary for proper functioning. Previous studies primarily focused on interference with the estrogen and/or androgen receptor, but the hormonal function may be disrupted in many more ways through pesticide exposure. The aim of this review is to give an overview of the various ways in which pesticides may disrupt the hormonal function of the female reproductive system and in particular the ovarian cycle. Disruption can occur in all stages of hormonal regulation: 1. hormone synthesis; 2. hormone release and storage; 3. hormone transport and clearance; 4. hormone receptor recognition and binding; 5. hormone postreceptor activation; 6. the thyroid function; and 7. the central nervous system. These mechanisms are described for effects of pesticide exposure in vitro and on experimental animals in vivo. For the latter, potential effects of endocrine disrupting pesticides on the female reproductive system, i.e. modulation of hormone concentrations, ovarian cycle irregularities, and impaired fertility, are also reviewed. In epidemiological studies, exposure to pesticides has been associated with menstrual cycle disturbances, reduced fertility, prolonged time-to-pregnancy, spontaneous abortion, stillbirths, and developmental defects, which may or may not be due to disruption of the female hormonal function. Because pesticides comprise a large number of distinct substances with dissimilar structures and diverse toxicity, it is most likely that several of the above-mentioned mechanisms are involved in the pathophysiological pathways explaining the role of pesticide exposure in ovarian cycle disturbances, ultimately leading to fertility problems and other reproductive effects. In future research, information on the ways in which pesticides may disrupt the hormonal function as described in this review, can be used to generate specific hypotheses for studies on the effects of pesticides on the ovarian cycle, both in toxicological and epidemiological settings.

• Reproductive disorders among male and female greenhouse workers

  Authors: Reini W. Bretveld, Mariëtte Hooiveld, Gerhard A. Zielhuis, Annelies Pellegrino, Iris A.L.M. van Rooij, Nel Roeleveld

  Reproductive Toxicology.

  The aim of this study was to evaluate reproductive disorders in male and female greenhouse workers. In 2002, data were collected from 4872 Dutch greenhouse workers and 8133 referents through postalThe aim of this study was to evaluate reproductive disorders in male and female greenhouse workers. In 2002, data were collected from 4872 Dutch greenhouse workers and 8133 referents through postal questionnaires with detailed questions on reproductive disorders of the most recent pregnancy, lifestyle habits, and occupational exposures (e.g. pesticides) prior to conception. Different reproductive outcome measures were compared between 957 male and 101 female greenhouse workers and 1408 referents by means of logistic regression analyses. The analyses of primigravidous couples showed a slightly elevated risk of prolonged TTP (ORwomen = 1.9; 95% CI: 0.8–4.4) and an increased risk of spontaneous abortion among female greenhouse workers (ORwomen = 4.0; 95% CI: 1.1–14.0). A decreased risk of preterm birth was found among male greenhouse workers (ORmen = 0.1; 95% CI: 0.03–0.5). This study may offer some evidence for the hypothesis that pesticide exposure affects human reproduction leading to spontaneous abortion and possibly to prolonged time-to-pregnancy.