Marleen M.H.J. van Gelder

Web-based Questionnaires: The Future in Epidemiology?

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 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.

Clinical Importance of Streptococcus gallolyticus Infection Among Colorectal Cancer Patients: Systematic Review and Meta-analysis

BACKGROUND Streptococcus bovis has long been associated with colorectal cancer (CRC). However, not all genospecies are as closely related to CRC. With this systematic review, we aim to increase the awareness of the association between S. bovis biotype I (Streptococcus gallolyticus) and CRC and urge for uniform molecular microbiological classification. METHODS In January 2011, the PubMed database was searched for all studies that investigated the association between S. bovis, infective endocarditis (IE), and CRC. A total of 191 studies were screened for eligibility and yielded 52 case reports and 31 case series, of which 11 were used for meta-analysis on the association between S. bovis biotype, IE, and adenomas/carcinomas (CRC). RESULTS Among the S. bovis-infected patients who underwent colonic evaluation, the median percentage of patients who had concomitant adenomas/carcinomas was 60% (interquartile range, 22%), which largely exceeds the disease rate reported in the general asymptomatic population. Meta-analysis showed that patients with S. bovis biotype I infection had a strongly increased risk of having CRC (pooled odds ratio [OR], 7.26; 95% confidence interval [CI], 3.94-13.36) and IE (pooled OR, 16.61; 95% CI, 8.85-31.16), compared with S. bovis biotype II-infected patients. Notably, CRC occurred more often among patients with S. bovis IE than among patients with S. bovis infection at other sites (pooled OR, 3.72; 95% CI, 2.03-6.81). CONCLUSIONS Our meta-analysis clearly indicates that S. bovis should no longer be regarded as a single species in clinical practice, because S. gallolyticus (S. bovis biotype I) infection, in particular, has an unambiguous association with CRC.

Teratogenic mechanisms of medical drugs

BACKGROUND Although prescription drug use is common during pregnancy, the human teratogenic risks are undetermined for more than 90% of drug treatments approved in the USA during the past decades. A particular birth defect may have its origins through multiple mechanisms and possible exposures, including medications. A specific pathogenic process may result in different outcomes depending upon factors such as embryonic age at which a drug is administered, duration and dose of exposure and genetic susceptibility. This review focuses on the teratogenic mechanisms associated with a number of medications. METHODS We used three methods to identify the teratogenic mechanisms of medications: the MEDLINE and EMBASE databases, two recent books on teratogenic agents and a list of drugs classified as U.S. Food and Drug Administration class D or X. Mechanisms were included only if they are associated with major structural birth defects and medications that are used relatively frequently by women of reproductive age. RESULTS We identified six teratogenic mechanisms associated with medication use: folate antagonism, neural crest cell disruption, endocrine disruption, oxidative stress, vascular disruption and specific receptor- or enzyme-mediated teratogenesis. Many medications classified as class X are associated with at least one of these mechanisms. CONCLUSIONS Identifying teratogenic mechanisms may not only be relevant for etiologic and post-marketing research, but may also have implications for drug development and prescribing behavior for women of reproductive age, especially since combinations of seemingly unrelated prescription and over the counter medications may utilize similar teratogenic mechanisms with a resultant increased risk of birth defects.

Characteristics of pregnant illicit drug users and associations between cannabis use and perinatal outcome in a population-based study

BACKGROUND According to the 2004 National Survey on Drug Use and Health, 4.6% of American women reported use of an illicit drug during pregnancy. Previous studies on illicit drug use during pregnancy and perinatal outcomes showed inconsistent results. METHODS This population-based study included mothers who delivered live-born infants without birth defects between 1997 and 2004 and completed interviews for the National Birth Defects Prevention Study (response rate 69%; n=5871). Prevalence of self-reported illicit drug use (specifically cannabis, cocaine, and stimulants) during pregnancy and its associations with demographic and social factors were assessed. We used multivariable linear and logistic regression analyses to study the associations of cannabis use with birth weight and gestational age. RESULTS The prevalence of reported illicit drug use during pregnancy was 3.6% (standard error 0.24). Pregnant users of cannabis, cocaine, and stimulants were younger, had a lower level of education and lower household income, and were less likely to have used folic acid in the periconceptional period than nonusers. Illicit drug users were also more likely to have used alcohol and tobacco. After adjustment for confounding, cannabis use was not associated with mean birth weight or gestational age or with low birth weight or preterm delivery. CONCLUSION Women who report use of illicit drugs during pregnancy differ in demographic and socioeconomic background from nonusers. Reported cannabis use does not seem to be associated with low birth weight or preterm birth.

Exposure to non-steroidal anti-inflammatory drugs during pregnancy and the risk of selected birth defects: a prospective cohort study

Background Since use of non-steroidal anti-inflammatory drugs (NSAIDs) during pregnancy is common, small increases in the risk of birth defects may have significant implications for public health. Results of human studies on the teratogenic risks of NSAIDs are inconsistent. Therefore, we evaluated the risk of selected birth defects after prenatal exposure to prescribed and over-the-counter NSAIDs. Methods and Findings We used data on 69,929 women enrolled in the Norwegian Mother and Child Cohort Study between 1999 and 2006. Data on NSAID exposure were available from a self-administered questionnaire completed around gestational week 17. Information on pregnancy outcome was obtained from the Medical Birth Registry of Norway. Only birth defects suspected to be associated with NSAID exposure based upon proposed teratogenic mechanisms and previous studies were included in the multivariable logistic regression analyses. A total of 3,023 women used NSAIDs in gestational weeks 0–12 and 64,074 women did not report NSAID use in early pregnancy. No associations were observed between overall exposure to NSAIDs during pregnancy and the selected birth defects separately or as a group (adjusted odds ratio 0.7, 95% confidence interval 0.4–1.1). Associations between maternal use of specific types of NSAIDs and the selected birth defects were not found either, although an increased risk was seen for septal defects and exposure to multiple NSAIDs based on small numbers (2 exposed cases; crude odds ratio 3.9, 95% confidence interval 0.9–15.7). Conclusions Exposure to NSAIDs during the first 12 weeks of gestation does not seem to be associated with an increased risk of the selected birth defects. However, due to the small numbers of NSAID-exposed infants for the individual birth defect categories, increases in the risks of specific birth defects could not be excluded.

Rationale and Design of the PRegnancy and Infant DEvelopment (PRIDE) Study

Background To optimise the health of pregnant women and their children by evidence-based primary and secondary prevention, more scientific knowledge is needed. To overcome the methodological limitations of many studies on pregnancy and child health, which often use a retrospective design, we established the PRIDE (PRegnancy and Infant DEvelopment) Study. Methods and Results The PRIDE Study is a large prospective cohort study that aims at including 150 000–200 000 women in early pregnancy to study a broad range of research questions pertaining to pregnancy complications, maternal and child health, and adverse developmental effects in offspring. Women are invited to participate by their prenatal care provider before or at their first prenatal care visit and are asked to fill out web-based questionnaires in gestational weeks 8–10, 17, and 34, as well as biannually throughout childhood. In addition, a food frequency questionnaire and a paternal questionnaire are administered and medical records are consulted. Multiple validation studies will be conducted and paper-and-pencil questionnaires are available for women who cannot or do not want to participate through the Internet. For subgroups of participants, blood and saliva samples for genetic and biochemical analyses are being collected. The pilot phase, which started in July 2011, showed a response rate of 47%. Recruitment will eventually cover all of the Netherlands. Conclusions We expect that this study, which will be the largest birth cohort in the world so far, will provide new insights in the aetiology of disorders and diseases that originate in pregnancy. The PRIDE Study is open for collaboration.

Neurodevelopmental problems at 18 months among children exposed to paracetamol in utero: a propensity score matched cohort study

Background Previous studies showed that children exposed to paracetamol during fetal life might have an increased risk of neurodevelopmental problems. Since paracetamol is one of the most commonly used medications during pregnancy, even small increases in the risk of neurodevelopmental problems may have considerable implications for public health. Methods Using data from the Norwegian Mother and Child Cohort Study, we applied propensity score (PS) matching to examine associations between prenatal paracetamol exposure and neurodevelopmental problems among children at 18 months of age. Paracetamol use was classified into short-term (< 28 days) and long-term (≥ 28 days) of exposure. Results Of the 51 200 pregnancies included in our study, 40.5% of mothers ( n  = 20 749) used paracetamol at least once during pregnancy. In the PS-matched analyses, long-term paracetamol exposure during pregnancy was associated with communication problems [odds ratio (OR): 1.38, 95% confidence interval (CI) 0.98-1.95) and delayed motor milestone attainment (OR: 1.35, 95% CI 1.07-1.70). We did not observe increased risks after short-term exposure. Sensitivity analyses for several indications showed similar effects as the PS-matched analyses, suggesting no confounding by indication. Conclusion Long-term exposure to paracetamol in utero was associated with modestly increased risks of motor milestone delay and impaired communication skills among children at 18 months. Caution is warranted when considering long-term use of paracetamol during pregnancy; however, women with severe pain conditions should not be deprived of appropriate pharmacotherapy.

Drugs associated with teratogenic mechanisms. Part II: a literature review of the evidence on human risks

STUDY QUESTION What is the current state of knowledge on the human risks of drugs suspected to be associated with teratogenic mechanisms? SUMMARY ANSWER Evidence for the presence or absence of human risks of birth defects is scarce or non-existent for the majority of drugs associated with teratogenic mechanisms. WHAT IS KNOWN ALREADY Medical drugs suspected to be associated with teratogenic mechanisms are dispensed to a significant proportion of women in the first trimester of pregnancy. However, an overview of the current state of knowledge on the human teratogenic effects of these drugs is lacking. STUDY DESIGN, SIZE, DURATION We performed an extensive literature review of studies in the English language which examined the associations between selected drugs and specific birth defects. The literature was identified from MEDLINE and EMBASE from database inception (January 1946 and January 1974, respectively) through December 2012 using 287 terms for the drugs of interest. We only included studies if they specified birth defect subtypes and, specifically for cohort studies, involved live born infants. PARTICIPANTS/MATERIALS, SETTING, METHODS Of 14 406 potentially relevant articles, 556 full-text articles were assessed for eligibility and 250 met the inclusion criteria. The studies included were divided into four categories according to their design to increase the validity of our study. MAIN RESULTS AND THE ROLE OF CHANCE Epidemiologic studies assessing teratogenic risks were identified for less than half of the drugs included in the review. A substantial variation in study design and data collection methods was observed. When the data collection method is of questionable validity, study quality may be affected considerably. For only 15 drugs of interest, birth defects were assessed in at least 1000 infants in cohort studies, and 13 of these were associated with one or more specific birth defects. The majority of associations observed in case-control studies are as yet unconfirmed. For most drugs and drug groups, however, the numbers of exposed infants studied were too small to draw any conclusions regarding their human teratogenic risks. LIMITATIONS, REASONS FOR CAUTION The validity of our review is limited by the validity and reporting of the studies from which the data were extracted. Some relevant studies might have been missed owing to the exclusion of articles not in the English language and publication bias. WIDER IMPLICATIONS OF THE FINDINGS It is a cause of concern that the drugs most often dispensed in the first trimester of pregnancy are not necessarily the drugs for which teratogenic risks have been studied. Future studies should focus on those drugs that are most commonly used during pregnancy and for which the teratogenic risks are unknown, such as iron preparations, serotonin receptor agonists or antagonists, drugs used in fertility treatment, dihydrofolate reductase inhibitors. STUDY FUNDING/COMPETING INTEREST(S) Marleen van Gelder was supported by the Netherlands Organisation for Scientific Research/NWO (grant no. 021.001.008). No competing interests are declared. TRIAL REGISTRATION NUMBER N/A.

Pharmacogenetics of drug-induced birth defects: what is known so far?

A literature review was performed to collect information on the role of pharmacogenetics in six proposed teratogenic mechanisms associated with drug use during pregnancy: folate antagonism, oxidative stress, angiotensin-converting enzyme inhibition and angiotensin II receptor antagonism, cyclooxygenase-1 and -2 inhibition, 5-hydroxytryptamine-reuptake inhibition and drug transporters in the placenta. Data on the direct relationship between pharmacogenetics and drug-induced birth defects were found for folate metabolism, oxidative stress caused by phenytoin exposure and drug transporters in the placenta. Although no specific data to support pharmacogenetic-related birth defects were found for the NSAIDs, paroxetine and fluoxetine, it might be expected that polymorphisms modify their teratogenic effects. The usually low prevalence of drug-induced malformations impedes the demonstration of the contribution of pharmacogenetics. Large-scale studies, preferably case-control studies, are needed.

Reproductive Health Characteristics of Marijuana And Cocaine Users: Results from the 2002 National Survey of Family Growth

CONTEXT Illicit drug use is associated with risky sexual behaviors in adolescents and young adults. However, few studies have examined these associations among drug users of all reproductive ages, using a control group of nonusers. METHODS Associations between marijuana and cocaine use, and outcomes related to sexual behaviors and reproductive health, were assessed using data from the 2002 National Survey of Family Growth. Overall, 4,928 men and 7,643 women aged 15-44 were interviewed. Chi-square tests, t tests and multivariable logistic regression analyses were used; in supplementary analyses, men and women were stratified by age-group (25 or younger, and older than 25), to capture the understudied older adults who use drugs. RESULTS Twenty-seven percent of men and 16% of women reported use of marijuana or cocaine in the last year. Drug users were younger than nonusers at first vaginal sex (mean, 15.2-16.1 vs. 17.3-17.5 years) and were more likely to have engaged in risky sexual behaviors in the last year, including having had sex with a nonmonogamous partner (odds ratios, 3.3-5.2 for men and 2.9-6.5 for women), while high on alcohol or drugs (10.1-18.0 and 8.1-24.2), or in exchange for money or drugs (2.7-2.8 and 2.3-9.2). They also were more likely to have undergone STD testing or treatment. Drug use was associated with risky sexual behaviors in both age-groups. CONCLUSION Programs aimed at reducing sexual risks among drug users should address the behaviors of men and women of all reproductive ages.