Congenital anomalies in the offspring of occupationally exposed mothers: a systematic review and meta-analysis of studies using expert assessment for occupational exposures.

STUDY QUESTION: Is there an association between maternal occupational exposure to solvents, pesticides and metals as assessed by expert-based assessment and congenital anomalies in the offspring? SUMMARY ANSWER: There is an association between maternal occupational exposure to solvents and congenital anomalies in the offspring, including neural tube defects, congenital heart defects and orofacial clefts. WHAT IS KNOWN ALREADY: One important environmental risk factor for development of congenital anomalies is maternal occupational exposure to chemicals in the workplace prior to and during pregnancy. A number of studies have assessed the association with often conflicting results, possibly due to different occupational exposure assessing methods. STUDY DESIGN, SIZE, DURATION: For this systematic review with meta-analysis, the search terms included maternal occupation, exposure, congenital anomalies and offspring. Electronic databases MEDLINE and EMBASE were searched for English studies up to October 2017. PARTICIPANTS/MATERIALS, SETTING, METHODS: Two reviewers independently screened all citations identified by the search. Case-control studies and cohort studies were included if (I) they reported on the association between maternal occupational exposure to solvents, pesticides or metals and congenital anomalies, and (II) assessment of occupational exposure was performed by experts. Data on study characteristics, confounders and odds ratios (ORs) were extracted from the included studies for four subgroups of congenital anomalies. Methodological quality was assessed using the Newcastle-Ottawa Scale. In the meta-analysis, random effects models were used to pool estimates. MAIN RESULTS AND THE ROLE OF CHANCE: In total, 2806 titles and abstracts and 176 full text papers were screened. Finally, 28 studies met the selection criteria, and 27 studies could be included in the meta-analysis. Our meta-analysis showed that maternal occupational exposure to solvents was associated with neural tube defects (OR: 1.51, 95%CI: 1.09-2.09) and congenital heart defects (OR: 1.31, 95%CI:1.06-1.63) in the offspring. Also maternal occupational exposure to glycol ethers, a subgroup of solvents, was associated with neural tube defects (OR: 1.93, 95%CI: 1.17-3.18) and orofacial clefts (OR: 1.95, 95%CI: 1.38-2.75) in the offspring. Only one study investigated the association between maternal occupational exposure to solvents and hypospadias and found an association (OR: 3.63, 95%CI: 1.94-7.17). Results of the included studies were consistent. In our meta-analysis, we found no associations between occupational exposure to pesticides or metals and congenital anomalies in the offspring. LIMITATIONS, REASONS FOR CAUTION: A limited number of studies was included, which made it impossible to calculate pooled estimates for all congenital anomalies, analyse individual chemicals or calculate exposure-response relations. Bias could have been introduced because not all included studies corrected for potentially confounding factors. WIDER IMPLICATIONS OF THE FINDINGS: Employers and female employees should be aware of the possible teratogenic effects of solvent exposure at the workplace. Therefore, is it important that clinicians and occupational health specialist provide women with preconception advice on occupational solvent exposure, to reduce the congenital anomaly risk. STUDY FUNDING/COMPETING INTEREST(S): NSp was paid by the Graduate School of Medical Sciences (MD/PhD program), UMCG, Groningen, the Netherlands. EUROCAT Northern Netherlands is funded by the Dutch Ministry of Health, Welfare and Sports. There are no competing interests. REGISTRATION NUMBER: CRD42017053943.

Genotoxicidad de los nanomateriales, grandes discrepancias y desafíos / Genotoxicity of nanomaterials, discrepancies and challenges

La nanotecnología es el estudio, diseño, creación, síntesis, manipulación y aplicación de materiales a través del control de la materia a escala nanométrica, entre 1 a 100 nanómetros. Se considera que la nanoteconología está revolucionando nuestro mundo. Los nanomateriales son ampliamente utilizados en diferentes campos por sus propiedades únicas pero también pueden causar efectos adversos tanto para la salud humana como para el ambiente, por lo que es necesario conocer los riesgos y los factores que incrementan estos efectos adversos. En esta revisión abordamos los nanomateriales y sus tipos, los aspectos tóxicos con énfasis en el efecto genotóxico, ya que por sus implicaciones de daños en el ADN pueden iniciar y promover la carcinogénesis, o afectar la fertilidad, ciertas consideraciones que deben tomarse en cuenta en el momento de la evaluación genotóxica de los NMs. Aunque existe cierta evidencia de alteraciones al exponer las células a los nanomateriales, todavía existen deficiencias e inconsistencias en la literatura y en las normativas para conocer las características físico-químicas de los nanomateriales, cómo actúan, y sus posibles cambios con el tiempo (AU)

Nanotechnology is the study, design, creation, synthesis, manipulation and application of materials through the control of matter at the nanometer scale, between 1-100 nanometers. Nanotechnology is revolutionizing our world. Nanomaterials are widely used in various fields thanks to their unique properties. However, nanomaterials can also result in adverse health effects and the environment, it is necessary to know the risks and factors that increase these effects. In this review we focus on nanomaterials and their types, the toxic aspects of nanoparticles; with emphasis on the genotoxic effects and DNA damage that can initiate or promote carcinogenesis or affect fertility as well as the guidelines for the application of genotoxicity tests. Although there is some evidence of changes that occur when cells are exposed to nanomaterials, there is still a dearth of consistent results in the literature and in regulatory documents in terms of physicochemical characteristics of nanomaterials, their mechanisms, and exposure (AU)

Potential toxic effects of glyphosate and its commercial formulations below regulatory limits.

Glyphosate-based herbicides (GlyBH), including Roundup, are the most widely used pesticides worldwide. Their uses have increased exponentially since their introduction on the market. Residue levels in food or water, as well as human exposures, are escalating. We have reviewed the toxic effects of GlyBH measured below regulatory limits by evaluating the published literature and regulatory reports. We reveal a coherent body of evidence indicating that GlyBH could be toxic below the regulatory lowest observed adverse effect level for chronic toxic effects. It includes teratogenic, tumorigenic and hepatorenal effects. They could be explained by endocrine disruption and oxidative stress, causing metabolic alterations, depending on dose and exposure time. Some effects were detected in the range of the recommended acceptable daily intake. Toxic effects of commercial formulations can also be explained by GlyBH adjuvants, which have their own toxicity, but also enhance glyphosate toxicity. These challenge the assumption of safety of GlyBH at the levels at which they contaminate food and the environment, albeit these levels may fall below regulatory thresholds. Neurodevelopmental, reproductive, and transgenerational effects of GlyBH must be revisited, since a growing body of knowledge suggests the predominance of endocrine disrupting mechanisms caused by environmentally relevant levels of exposure.

Hazard and risk assessment of teratogenic chemicals under REACH.

In 2007, a new European chemicals legislation was implemented: Regulation (EC) No. 1907/2006, also known as "REACH." It obliges companies to take the main responsibility for the valid information on the safe use of the chemicals they manufacture and/or place on the European market. So they must, for example, register their chemicals at the European Chemicals Agency (ECHA) and submit extensive substance-related registration dossiers containing information on the substances' intrinsic hazardous properties and documentation of their risk assessment. REACH regulates the registration and evaluation process as well as the authorization and restriction procedure. In addition, classification, labeling, and packaging of chemicals apply in accordance with Regulation (EC) No. 1272/2008 ("CLP Regulation"). It implements almost completely the provisions of the United Nations Globally Harmonised System of Classification and Labelling of Chemicals (UN GHS) into European legislation and will fully replace the Dangerous Substances Directive (67/548/EEC) and the Dangerous Preparations Directive (1999/45/EC) by 2015. According to both the old and the new classification system, teratogenic chemicals are classified as developmental toxicants, with developmental toxicity falling within the hazard class of reproductive toxicity. REACH as well as the CLP Regulation provide several procedures in which reproductive toxicants take a special position because their harmful effects are considered particularly serious. Teratogenic substances are not explicitly named by these legal texts but, as they constitute as developmental toxicants a hazard differentiation of reproductive toxicity, they are implicitly always included by the provisions.

Balancing act: safe and evidence-based prescribing for women of reproductive age.

Teratogenic medications are commonly prescribed to women of reproductive age. Caring for women who may benefit from the use of teratogenic medications requires clinicians to engage patients in shared decision-making on the risks and benefits of medication use in the context of the patient's fertility goals, the implications of the patient's medical condition for a pregnancy and the risks and benefits of various contraceptive methods. Effective communication about all of these issues is essential to avoiding medication-induced birth defects. However, data suggest that such communication remains inadequate, leading some women to face unintentional exposure of a pregnancy to a teratogen, undesired pregnancy or, sometimes, the need for pregnancy termination services. This review outlines key information needed to ensure safe prescribing to women of childbearing age. It includes recommendations for changes in medical education, healthcare delivery and health policy to facilitate thoughtful prescribing and comprehensive care.

Isotretinoin use and compliance with the Dutch Pregnancy Prevention Programme: a retrospective cohort study in females of reproductive age using pharmacy dispensing data.

BACKGROUND: Isotretinoin is very effective in the treatment of severe acne. However, because of the teratogenic properties of this agent an isotretinoin Pregnancy Prevention Programme (PPP) was implemented in the Netherlands to guarantee that treatment is contraindicated in women of reproductive age unless at least one effective method of contraception is used. Furthermore, the PPP stipulates that isotretinoin treatment should be managed by physicians or specialists experienced in treatment with this drug and that only monthly prescriptions are issued. OBJECTIVE: To assess compliance with the Dutch isotretinoin PPP in women of reproductive age during the study period of 1 January 2005 to 31 December 2008. METHODS: Detailed information on dispensed medication and co-medication was available from the Dutch Foundation of Pharmaceutical Statistics. Four types of outcome were studied: concomitant dispensing of hormonal contraceptive with isotretinoin; the proportion of specialist prescribing of isotretinoin; prescribing of conventional acne therapy prior to isotretinoin initiation; and isotretinoin dispensing exceeding the maximum amount. The use of contraceptives in women aged between 15 and 45 years was defined as concomitant if the period of systemic contraceptive use overlapped the period of isotretinoin dispensing for at least 10 days, or if any dispensing of an intrauterine or intravaginal contraceptive was recorded since the year 2000. Dispensings were separated into those prescribed by either specialists or general practitioners (GPs). The use of antibacterials, antiandrogens or topical agents against acne was checked 4 months prior to an isotretinoin dispensing, and a possible excess of the maximum amount of isotretinoin was defined as prescriptions of more than 100 defined daily doses. RESULTS: During the study period, data were available for 442 Dutch pharmacies encompassing 4881 women of reproductive age using isotretinoin at least once during study period. Among women of reproductive age, the use of isotretinoin increased during the study period. The proportion of isotretinoin initiation with concomitant oral hormonal or intrauterine contraceptives was low (59.3% [95% CI 57.6, 61.0]). Initiation of isotretinoin by a specialist increased the chance for concomitant contraception by 26% (95% CI 6.0, 49.0); in 78.2% (95% CI 76.8, 79.6) of women, isotretinoin was initiated by a specialist. Conventional acne therapy up to 16 months prior to isotretinoin initiation was found in 70% of the women (70.3% [95% CI 66.0, 74.6]). In 1.4% (95% CI 1.0, 1.8) of cases of treatment initiation, the amount of isotretinoin dispensed on one prescription seemed too high. CONCLUSION: Attention should be paid to improving the implementation of the isotretinoin PPP. Despite clear guidelines and warnings in the product information, our study strongly suggests that concomitant use of isotretinoin and contraceptives is too low. Even though we will have missed non-pharmacological forms of contraception, these results raise doubts about the safe use of isotretinoin in women of reproductive age in the Netherlands. Furthermore, isotretinoin does not seem to be used in cases of severe acne only. Reserving isotretinoin prescribing to specialists may improve adherence to the PPP.

Maternal fumonisin exposure as a risk factor for neural tube defects.

Fumonisins are mycotoxins produced by the fungus F. verticillioides, a common contaminant of maize (corn) worldwide. Maternal consumption of fumonisin B(1)-contaminated maize during early pregnancy has recently been associated with increased risk for neural tube defects (NTDs) in human populations that rely heavily on maize as a dietary staple. Experimental administration of purified fumonisin to mice early in gestation also results in an increased incidence of NTDs in exposed offspring. Fumonisin inhibits the enzyme ceramide synthase in de novo sphingolipid biosynthesis, resulting in an elevation of free sphingoid bases and depletion of downstream glycosphingolipids. Increased sphingoid base metabolites (i.e., sphinganine-1-phosphate) may perturb signaling cascades involved in embryonic morphogenesis by functioning as ligands for sphingosine-1-P (S1P) receptors, a family of G-protein-coupled receptors that regulate key biological processes such as cell survival/proliferation, differentiation and migration. Fumonisin-induced depletion of glycosphingolipids impairs expression and function of the GPI-anchored folate receptor (Folr1), which may also contribute to adverse pregnancy outcomes. NTDs appear to be multifactorial in origin, involving complex gene-nutrient-environment interactions. Vitamin supplements containing folic acid have been shown to reduce the occurrence of NTDs, and may help protect the developing fetus from environmental teratogens. Fumonisins appear to be an environmental risk factor for birth defects, although other aspects of maternal nutrition and genetics play interactive roles in determining pregnancy outcome. Minimizing exposures to mycotoxins through enhanced agricultural practices, identifying biomarkers of exposure, characterizing mechanisms of toxicity, and improving maternal nutrition are all important strategies for reducing the NTD burden in susceptible human populations.

Human monitoring of phthalates and risk assessment.

Some phthalates, such as di(2-ethylhexyl) phthalate (DEHP) and dibutyl phthalate (DBP), and their metabolites are suspected of producing teratogenic and endocrino-disrupting effects. In this study, urinary levels of phthalates (DEHP, DBP, diethyl phthalate (DEP), butylbenzyl phthalate BBP), and monoethylhexyl phthalate (MEHP, a major metabolite of DEHP) were measured by high performance liquid chromatography (HPLC) in human populations (women [hospital visitors], n = 150, and children, n = 150). Daily exposure level of DEHP in children was estimated to be 12.4 microg/kg body weight/d (male 9.9 microg/kg body weight/d, female 17.8 microg/kg body weight/d), but, in women was estimated to be 41.7 microg/kg body weight/d, which exceeded the tolerable daily intake (TDI, 37 microg/kg body weight/day) level established by the European Union (EU) Scientific Committee for Toxicity, Ecotoxicity, and the Environment (SCTEE) based on reproductive toxicity. Based on these data, hazard indices (HIs) were calculated to be 1.12 (41.7/37 TDI) for women and 0.33 (12.4/37 TDI) for children, respectively. These data suggest that Koreans (women and children) were exposed to significant levels of phthalates, which should be reduced to as low a level as technologically feasible to protect Koreans from the exposure to toxic phthalates.

Embriopatía por isotretinoína / Isotretinoin-induced embryopathy

El ácido retinoico es un conocido teratógeno. Con el advenimiento de la isotretinoína para el tratamiento acné, su uso se ha incrementado ampliamente y con ello el peligro de marformaciones fetales. Se comunica un caso fatal de embriopatía inducida por isotretinoína, indicada para el tratamiento del acné en una mujer de 23 años. Se realiza una revisión bibliográfica y se remarca la importancia de las medidas de prevención cuando se prescriben retinoides sistémicos a una mujer en etapa fértil (AU)

Embriopatía por isotretinoína / Isotretinoin-induced embryopathy

El ácido retinoico es un conocido teratógeno. Con el advenimiento de la isotretinoína para el tratamiento acné, su uso se ha incrementado ampliamente y con ello el peligro de marformaciones fetales. Se comunica un caso fatal de embriopatía inducida por isotretinoína, indicada para el tratamiento del acné en una mujer de 23 años. Se realiza una revisión bibliográfica y se remarca la importancia de las medidas de prevención cuando se prescriben retinoides sistémicos a una mujer en etapa fértil

The European Community Directive on the classification and labeling of chemicals for reproductive toxicity.

The classification and labeling of dangerous substances was first introduced in 1967 in the European Community with Council Directive 67/548/EEC, known as the Dangerous Substances Directive. The Sixth Amendment to this directive in 1979 introduced a notification procedure for new chemicals and a requirement for labeling chemicals for toxicity. Three special categories for labeling were for carcinogenicity, mutagenicity, and teratogenicity. The teratogenicity classification was restricted to chemicals inducing teratogenic effects in the classical sense of the word, ie, producing only gross structural malformations. Discussions by expert advisors to the European Commission over several years led to a widening of concern in this area of toxicology and, under the recent Seventh Amendment, the classification of "teratology" has been changed to "toxic to reproduction." This includes adverse effects on fertility, pre- and postnatal development, and lactation, and encompasses not only structural but also functional deficits. This will bring about a major change in the testing requirements to allow adequate classification of chemicals for these other aspects of reproductive toxicity.

Methodological proposal in behavioural teratogenicity testing: assessment of propoxyphene, chlorpromazine, and vitamin A as positive controls.

Pregnant Sprague-Dawley rats received either 80 mg/kg d-propoxyphene HCl or 20 mg/kg chlorpromazine HCl or 80,000 and 160,000 IU/kg vitamin A palmitate daily between the 6th and 20th days of gestation. Vehicle control groups were similarly treated with saline or corn oil and considered as negative controls. Offspring were examined for physical landmarks, neuromotor development, and behaviour using righting reflex, swimming, negative geotaxis, open field, rotarod, water maze, and nocturnal activity. This test battery included biochemical measurements. No reduction in parental weight and physical offspring development was observed. All these treatments produced long-term changes in more than one test. Vitamin A palmitate (160,000 IU/kg) was judged as the best positive control with this test battery for future investigation of the behavioural teratology of drugs.