Use of Negative Control Exposure Analysis to Evaluate Confounding: An Example of Acetaminophen Exposure and Attention-Deficit/Hyperactivity Disorder in Nurses' Health Study II

Examining the relationship of acetaminophen use during pregnancy with early language development in children

BACKGROUND

Acetaminophen is the only analgesic considered safe for use throughout pregnancy. Recent studies suggest that use during pregnancy may be associated with poorer neurodevelopmental outcomes in children, but few have examined language development.

METHODS

The Illinois Kids Development Study is a prospective birth cohort in east-central Illinois. Between December 2013 and March 2020, 532 newborns were enrolled and had exposure data available. Participants reported the number of times they took acetaminophen six times across pregnancy. Language data were collected at 26.5-28.5 months using the MacArthur-Bates Communicative Development Inventories (CDI; n = 298), and 36-38 months using the Speech and Language Assessment Scale (SLAS; n = 254).

RESULTS

Taking more acetaminophen during the second or third trimester was associated with marginally smaller vocabularies and shorter utterance length (M3L) at 26.5-28.5 months. More acetaminophen use during the third trimester was also associated with increased odds of M3L scores ≤25th percentile in male children. More use during the second or third trimester was associated with lower SLAS scores at 36-38 months. Third trimester use was specifically related to lower SLAS scores in male children.

CONCLUSIONS

Higher prenatal acetaminophen use during pregnancy may be associated with poorer early language development.

IMPACT

Taking more acetaminophen during pregnancy, particularly during the second and third trimesters, was associated with poorer scores on measures of language development when children were 26.5-28.5 and 36-38 months of age. Only male children had lower scores in analyses stratified by child sex. To our knowledge, this is the first study that has used a standardized measure of language development to assess the potential impact of prenatal exposure to acetaminophen on language development. This study adds to the growing body of literature suggesting that the potential impact of acetaminophen use during pregnancy on fetal neurodevelopment should be carefully evaluated.

Drug-induced fetal and offspring disorders, beyond birth defects

Studies on drug utilization in western countries disclosed that about nine over ten women use at least one or more drugs during pregnancy. Determining whether a drug is safe or not in pregnant women is a challenge of all times. As a developing organism, the fetus is particularly vulnerable to effects of drugs used by the mother. Historically, research has predominantly focused on birth defects, which represent the most studied adverse pregnancy outcomes. However, drugs can also alter the ongoing process of pregnancy and impede the general growth of the fetus. Finally, adverse drug reactions can theoretically damage all developing systems, organs or tissues, such as the central nervous system or the immune system. This extensive review focuses on different aspects of drug-induced damages affecting the fetus or the newborn/infant, beyond birth defects, which are not addressed here.

The State of Use and Utility of Negative Controls in Pharmacoepidemiologic Studies

Uses of real-world data in drug safety and effectiveness studies are often challenged by various sources of bias. We undertook a systematic search of the published literature through September 2020 to evaluate the state of use and utility of negative controls to address bias in pharmacoepidemiologic studies. Two reviewers independently evaluated study eligibility and abstracted data. Our search identified 184 eligible studies for inclusion. Cohort studies (115, 63%) and administrative data (114, 62%) were, respectively, the most common study design and data type used. Most studies used negative control outcomes (91, 50%), and for most studies the target source of bias was unmeasured confounding (93, 51%). We identified 4 utility domains of negative controls: 1) bias detection (149, 81%), 2) bias correction (16, 9%), 3) P-value calibration (8, 4%), and 4) performance assessment of different methods used in drug safety studies (31, 17%). The most popular methodologies used were the 95% confidence interval and P-value calibration. In addition, we identified 2 reference sets with structured steps to check the causality assumption of the negative control. While negative controls are powerful tools in bias detection, we found many studies lacked checking the underlying assumptions. This article is part of a Special Collection on Pharmacoepidemiology.

Intergenerational transmission of tobacco smoking: The role of the child's behavioral difficulties. Data from the Danish National Birth cohort (DNBC)

AIMS

This study explores the role of offspring behavioral difficulties in the intergeneration transmission of tobacco smoking.

METHODS

This longitudinal cohort study is based on children born in Denmark in 1996-2003 participating in the Danish National Birth Cohort (DNBC), followed-up until 18years of age. We included mother-child pairs with complete data regarding the exposure (4 trajectories of maternal daily smoking quantity during pregnancy: low, intermediate/stable, intermediate/decreasing and high), outcome (offspring daily smoking status at 18 years) and mediator (offspring symptoms of hyperactivity-inattention at 11 years), that is 24,588 mother-child pairs.

RESULTS

In our study population, during pregnancy respectively 86.2%, 6.80%, 4.08% and 2.97% mothers belonged to the low, intermediate/stable, intermediate/decreasing and high smoking trajectory groups. After controlling for covariates using propensity scores, the direct effect of maternal smoking in pregnancy on offspring smoking in adolescence was statistically significant, especially when the mother belonged to the intermediate/stable smoking trajectory group (ORIPW = 2.09, 95% CI: 1.70 - 2.61) or to the high smoking trajectory group (ORIPW = 2.08, 95% CI: 1.52 - 3.11) compared to the low smoking trajectory group. None of the indirect effects of maternal smoking in pregnancy were statistically significant, and neither were the proportions mediated.

CONCLUSION

Maternal pregnancy smoking seems to have an influence on offspring smoking in early adulthood, which does not appear to be mediated by offspring behavioral difficulties. Women should be strongly encouraged to quit smoking in pregnancy to reduce both short and long-term health risks among their offspring.

The relationship of prenatal acetaminophen exposure and attention-related behavior in early childhood

Acetaminophen is currently the only analgesic considered safe for use throughout pregnancy, but recent studies indicate that prenatal exposure to acetaminophen may be related to poorer neurodevelopmental outcomes. Multiple studies have suggested that it may be associated with attention problems, but few have examined this association by trimester of exposure. The Illinois Kids Development Study is a prospective birth cohort located in east-central Illinois. Exposure data were collected between December 2013 and March 2020, and 535 newborns were enrolled during that period. Mothers reported the number of times they took acetaminophen at six time points across pregnancy. When children were 2, 3, and 4 years of age, caregivers completed the Child Behavior Checklist for ages 1.5-5 years (CBCL). Associations of acetaminophen use during pregnancy with scores on the Attention Problems and ADHD Problems syndrome scales, the Internalizing and Externalizing Behavior composite scales, and the Total Problems score were evaluated. Higher acetaminophen exposure during the second trimester of fetal development was associated with higher Attention Problems, ADHD Problems, Externalizing Behavior, and Total Problems scores at ages 2 and 3. Higher second trimester exposure was only associated with higher Externalizing Behavior and Total Problems scores at 4 years. Higher cumulative exposure across pregnancy was associated with higher Attention Problems and ADHD Problems scores at ages 2 and 3. Findings suggest that prenatal acetaminophen exposure, especially during the second trimester, may be related to problems with attention in early childhood.

In utero acetaminophen exposure and child neurodevelopmental outcomes: Systematic review and meta-analysis

BACKGROUND

Acetaminophen is a frequently used analgesic for pain and fever. There have been reports of adverse neurodevelopmental outcomes associated with in utero acetaminophen exposure. However, it is unclear whether this association is related directly to acetaminophen use, or the reasons for use.

OBJECTIVES

To summarise the literature on the association between in utero acetaminophen exposure and child neurodevelopmental outcomes, and assess the extent to which the association is due to confounding by indication.

DATA SOURCES

OVID for Medline, Embase, and PsycINFO, and EBSCO for CINAHL, from inception to August 18, 2022.

STUDY SELECTION AND DATA EXTRACTION

We searched for peer-reviewed, English-language studies on in utero acetaminophen exposure and child neurodevelopmental outcomes. Data were extracted using a standardised form created a priori, and quality was assessed using the Systematic Assessment of Quality in Observational Research.

SYNTHESIS

We generated pooled risk ratios (RR) for outcomes examined by ≥3 studies using random-effects models; outcomes that could not be meta-analysed were narratively summarised following Synthesis Without Meta-Analysis guidelines.

RESULTS

Twenty-two studies including 23 cohorts were eligible (n = 367,775 total participants; median: 51.7% with acetaminophen exposure). Studies were primarily prospective cohort studies from Europe and the US, with attention deficit/hyperactivity disorder (ADHD) being the most common outcome. Quality assessments resulted in 13.6% of studies being classified as high, 59.1% as medium, 22.7% as low, and 4.5% as very low quality. In utero acetaminophen exposure was associated with an elevated risk of ADHD (unadjusted pooled RR 1.32, 95% confidence interval [CI] 1.20, 1.44; I²  = 47%, n = 7 studies), with little difference after adjusting for confounders, including indications for acetaminophen use (adjusted pooled RR 1.34, 95% CI 1.15, 1.55; I²  = 50%, n = 4 studies).

CONCLUSIONS

Confounding by indication did not explain the association between in utero acetaminophen exposure and child ADHD. Further, high-quality research is needed on this and other neurodevelopmental outcomes.

Urinary paracetamol (4-acetaminophenol) and its isomer 2-acetaminophenol of Chinese pregnant women: Exposure characteristics and association with oxidative stress biomarkers

N-Acetyl-4-aminophenol (NA4AP, paracetamol/acetaminophen), a widely used pharmaceutical, is ubiquitous in urine samples of general population, raising concern about human health risks; oxidative stress is considered to be a mechanism for its toxicities. N-Acetyl-2-aminophenol (NA2AP) is an isomer of NA4AP; until now, few studies characterized exposure characteristics of NA4AP and NA2AP in pregnant women. In this work, NA4AP and NA2AP concentrations in urine samples (n = 2124) collected at three different trimesters were measured to examine their internal body burden among Chinese pregnant women (n = 708) and their associations with three oxidative stress biomarkers (OSBs, 8-OHG, 8-OHdG, and HNE-MA). NA4AP was detected in 100% of the urine samples (median concentration: 7.96 ng/mL); NA2AP was detected in 94.9% of them (median: 3.05 ng/mL). The intraclass correlation coefficients of their concentrations across three trimesters were poor (<0.4); correlations of NA4AP and NA2AP were weak (r: 0.15-0.23). Pregnant women who had higher household income or urine samples provided in summer (vs. winter) had higher concentrations of NA4AP. Pregnant women who had a college degree or above (vs. less than a high school education) had higher concentrations of NA2AP but urine samples provided in summer (vs. winter) had lower concentrations of NA2AP. The 95th percentile estimated daily intake of NA4AP (2,331 ng/kg-bw/d) based on averaged concentrations of the three trimesters was 40 times lower than the cRfD for NA4AP (2.33 vs. 93 μg/kg-bw/d). Urinary concentrations of NA4AP and NA2AP were associated with higher levels of the selected OSBs. For example, an interquartile range increase in NA4AP was associated with a 26.5% (95% CI: 23.6-29.6%) increase in 8-OHG, a 27.5% (95% CI: 23.8-31.3%) increase in 8-OHdG, and a 33.4% (95% CI: 24.7-42.7%) increase in HNE-MA (p < 0.05). This is the first study to measure their concentrations repeatedly over three trimesters, examine their exposure characteristics, and reveal their associations with the selected OSBs in pregnant women. Further studies are needed to identify non-intentional exposure sources of NA4AP, NA2AP, and another isomer of them (i.e., N-acetyl-3-aminophenol), as well as more health risks related to their exposure.

The Main Changes in Pregnancy—Therapeutic Approach to Musculoskeletal Pain

Background and Objectives: During pregnancy, women undergo various physiological and anatomical changes that are accentuated as the pregnancy progresses, but return to their previous state a few weeks/months after the pregnancy. However, a targeted therapeutic approach is needed. Most of the time, during this period, these changes precipitate the appearance of pain, musculoskeletal pain being the most common. Pregnant women should avoid treating musculoskeletal pain with medication and should choose alternative and complementary methods. Exercise along with rest is the basis for treating chronic musculoskeletal pain. Side effects of physical therapy are rare and, in addition, it is not contraindicated in pregnant women. The benefits of this type of treatment in combating pain far outweigh the risks, being an easy way to improve quality of life. The objective of this article is to discuss the management of musculoskeletal pain during pregnancy, to identify the main musculoskeletal pain encountered in pregnant women along with drug treatment, and to expose the beneficial effects of alternative and complementary methods in combating pain. Materials and Methods: A literature search was conducted using medical databases, including PubMed, Google Scholar, and ScienceDirect, using the keywords “changes of pregnancy”, “musculoskeletal pain”, “pregnancy pain”, “pain management”, “pharmacological approach”, “alternative and complementary treatment” and specific sites. Information was collected from studies whose target population included pregnant women who complained of musculoskeletal pain during the 9 months of pregnancy; pregnant women with other pathologies that could increase their pain were not included in this review. Results: The articles related to the most common non-obstetric musculoskeletal pain in pregnancy along with pharmacological treatment options and alternative and complementary methods for musculoskeletal pain management during pregnancy were selected. Conclusions: The results were used to guide information towards the safest methods of therapy but also to raise awareness of the treatment criteria in order to compare the effectiveness of existing methods. Treatment must consider the implications for the mother and fetus, optimizing non-pharmacological therapeutic options.

Associations of paternal and maternal per- and polyfluoroalkyl substances exposure with cord serum reproductive hormones, placental steroidogenic enzyme and birth weight

BACKGROUND

Maternal per- and polyfluoroalkyl substances (PFAS) exposure has been associated with placental function and fetal growth measures. However, few studies have simultaneously investigated paternal and maternal exposure effects.

OBJECTIVES

We evaluated the associations of paternal or maternal PFAS levels with placental function and fetal growth measures.

METHODS

We studied six PFAS measured in matched parental serums collected within 3 days before delivery in a birth cohort from LaiZhouWan, China. Outcomes evaluated include cord serum estradiol (n = 351), testosterone (n = 349), placental P450aromatase (n = 125), and birth weight (n = 369). Multiple linear regression was applied to estimate the associations for these outcomes according to paternal or maternal PFAS level after adjusting for socio-demographic confounders. Co-adjustment analysis of both paternal and maternal PFAS in the same model was performed.

RESULTS

Maternal and paternal PFAS levels were correlated (Spearman's r = 0.23-0.45). Maternal PFAS were associated with increased estradiol (e.g.

, PFOA

β = 0.03, 95%CI: 0.00, 0.07), testosterone (e.g.

, PFUA

β = 0.14, 95%CI: 0.00, 0.27), and P450aromatase (e.g.

, PFOA

β = 0.13, 95%CI: 0.04, 0.22). Maternal PFAS were also associated with a lower mean of birth weight but the estimated 95% CI included the null. Paternal PFAS were not associated with any of the outcomes evaluated.

CONCLUSIONS

Several maternal PFAS were associated with fetal steroid hormones and placental enzymes. Despite a correlation of PFAS level within the couples, no association was found for paternal PFAS exposure on these outcomes. The findings suggest the intrauterine PFAS exposure effect on fetal endocrine hormones and growth is unlikely to be confounded by exposure sources or familial factors shared within the couples.

Paracetamol use during pregnancy - a call for precautionary action

Paracetamol (N-acetyl-p-aminophenol (APAP), otherwise known as acetaminophen) is the active ingredient in more than 600 medications used to relieve mild to moderate pain and reduce fever. APAP is widely used by pregnant women as governmental agencies, including the FDA and EMA, have long considered APAP appropriate for use during pregnancy when used as directed. However, increasing experimental and epidemiological research suggests that prenatal exposure to APAP might alter fetal development, which could increase the risks of some neurodevelopmental, reproductive and urogenital disorders. Here we summarize this evidence and call for precautionary action through a focused research effort and by increasing awareness among health professionals and pregnant women. APAP is an important medication and alternatives for treatment of high fever and severe pain are limited. We recommend that pregnant women should be cautioned at the beginning of pregnancy to: forego APAP unless its use is medically indicated; consult with a physician or pharmacist if they are uncertain whether use is indicated and before using on a long-term basis; and minimize exposure by using the lowest effective dose for the shortest possible time. We suggest specific actions to implement these recommendations. This Consensus Statement reflects our concerns and is currently supported by 91 scientists, clinicians and public health professionals from across the globe.

Paracetamol (Acetaminophen) and the Developing Brain

Paracetamol is commonly used to treat fever and pain in pregnant women, but there are growing concerns that this may cause attention deficit hyperactivity disorder and autism spectrum disorder in the offspring. A growing number of epidemiological studies suggests that relative risks for these disorders increase by an average of about 25% following intrauterine paracetamol exposure. The data analyzed point to a dose-effect relationship but cannot fully account for unmeasured confounders, notably indication and genetic transmission. Only few experimental investigations have addressed this issue. Altered behavior has been demonstrated in offspring of paracetamol-gavaged pregnant rats, and paracetamol given at or prior to day 10 of life to newborn mice resulted in altered locomotor activity in response to a novel home environment in adulthood and blunted the analgesic effect of paracetamol given to adult animals. The molecular mechanisms that might mediate these effects are unknown. Paracetamol has diverse pharmacologic actions. It reduces prostaglandin formation via competitive inhibition of the peroxidase moiety of prostaglandin H2 synthase, while its metabolite N-arachidonoyl-phenolamine activates transient vanilloid-subtype 1 receptors and interferes with cannabinoid receptor signaling. The metabolite N-acetyl-p-benzo-quinone-imine, which is pivotal for liver damage after overdosing, exerts oxidative stress and depletes glutathione in the brain already at dosages below the hepatic toxicity threshold. Given the widespread use of paracetamol during pregnancy and the lack of safe alternatives, its impact on the developing brain deserves further investigation.

Perinatal Acetaminophen Exposure and Childhood Attention-Deficit/Hyperactivity Disorder (ADHD): Exploring the Role of Umbilical Cord Plasma Metabolites in Oxidative Stress Pathways

Oxidative stress mechanisms may explain associations between perinatal acetaminophen exposure and childhood attention-deficit hyperactivity disorder (ADHD). We investigated whether the changes in umbilical cord plasma amino acids needed to synthesize the antioxidant glutathione and in the oxidative stress biomarker 8-hydroxy-deoxyguanosine may explain the association between cord plasma acetaminophen and ADHD in the Boston Birth Cohort (BBC). Mother–child dyads were followed at the Boston Medical Center between 1998 and 2018. Cord plasma analytes were measured from archived samples collected at birth. Physician diagnoses of childhood ADHD were obtained from medical records. The final sample consisted of 568 participants (child mean age [SD]: 9.3 [3.5] years, 315 (52.8%) male, 248 (43.7%) ADHD, 320 (56.3%) neurotypical development). Cord unmetabolized acetaminophen was positively correlated with methionine (R = 0.33, p < 0.001), serine (R = 0.30, p < 0.001), glycine (R = 0.34, p < 0.001), and glutamate (R = 0.16, p < 0.001). Children with cord acetaminophen levels >50th percentile appeared to have higher risk of ADHD for each increase in cord 8-hydroxy-deoxyguanosine level. Adjusting for covariates, increasing cord methionine, glycine, serine, and 8-hydroxy-deoxyguanosine were associated with significantly higher odds for childhood ADHD. Cord methionine statistically mediated 22.1% (natural indirect effect logOR = 0.167, SE = 0.071, p = 0.019) and glycine mediated 22.0% (natural indirect effect logOR = 0.166, SE = 0.078, p = 0.032) of the association between cord acetaminophen >50th percentile with ADHD. Our findings provide some clues, but additional investigation into oxidative stress pathways and the association of acetaminophen exposure and childhood ADHD is warranted.

Behavioral Problems at Age 11 Years After Prenatal and Postnatal Exposure to Acetaminophen: Parent-Reported and Self-Reported Outcomes

Several studies have reported associations between prenatal acetaminophen exposure and behavioral outcomes in young children. We aimed to evaluate the associations of prenatal and postnatal exposures to acetaminophen with behavioral problems in children at age 11 years, using behavioral measures reported by parents and children. We studied 40,934 mother-child pairs from the Danish National Birth Cohort enrolled during 1996-2002. Parent-reported and child-reported Strengths and Difficulties Questionnaire (SDQ) responses were collected during the 11-year follow-up. We estimated risk ratios for behavioral problems including total difficulties as well as internalizing or externalizing behaviors following prenatal (during pregnancy) or postnatal (within the first 18 months after birth) acetaminophen exposure. Parent-reported and child-reported SDQ scores were moderately correlated; higher for externalizing (r = 0.59) than internalizing (r = 0.49) behaviors. Prenatal acetaminophen exposure was associated with 10%-40% higher risks for total difficulties and internalizing and externalizing problems based on parent- or child-reported SDQ, with the association being stronger for greater cumulative weeks of acetaminophen use. Postnatal exposure was associated with 16%-19% higher risks for parent-reported internalizing behaviors, but the associations were weak or null for child-reported scores except for prosocial behavior. Our study corroborates published associations between prenatal exposures to acetaminophen and behavioral problems and extends the literature to early adolescence.

Association Between Omega-3 Fatty Acid Levels and Risk for Incident Major Bleeding Events and Atrial Fibrillation: MESA

Background Randomized trials of pharmacologic strength omega-3 fatty acid (n3-FA)-based therapies suggest a dose-dependent cardiovascular benefit. Whether blood n3-FA levels also mediate safety signals observed in these trials, such as increased bleeding and atrial fibrillation (AF), remains uncertain. We hypothesized that higher baseline n3-FA levels would be associated with incident bleeding and AF events in MESA (Multi-Ethnic Study of Atherosclerosis), which included a population free of clinical cardiovascular disease at baseline. Methods and Results We examined the association between baseline plasma n3-FA levels (expressed as percent mass of total fatty acid) with incident bleeding and AF in MESA, an ongoing prospective cohort study. Bleeding events were identified from review of hospitalization International Classification of Diseases, Ninth Revision (ICD-9), and International Classification of Diseases, Tenth Revision (ICD-10), codes, and AF from participant report, discharge diagnoses, Medicare claims data, and study ECGs performed at MESA visit 5. Separate multivariable Cox proportional hazard modeling was used to estimate hazard ratios of the association of continuous n3-FA (log eicosapentaenoic acid [EPA], log docosahexaenoic acid [DHA], log [EPA+DHA]) and incident hospitalized bleeding events and AF. Among 6546 participants, the mean age was 62.1 years and 53% were women. For incident bleeding, consistent statistically significant associations with lower rates were seen with increasing levels of EPA and EPA+DHA in unadjusted and adjusted models including medications that modulate bleeding risk (aspirin, NSAIDS, corticosteroids, and proton pump inhibitors). For incident AF, a significant association with lower rates was seen with increasing levels of DHA, but not for EPA or EPA+DHA. Conclusions In MESA, higher plasma levels of n3-FA (EPA and EPA+DHA, but not DHA) were associated with significantly fewer hospitalized bleeding events, and higher DHA levels (but not EPA or EPA+DHA) with fewer incident AF events.

Prenatal exposure to non-steroidal anti-inflammatory drugs and risk of attention-deficit/hyperactivity disorder: A follow-up study in the Norwegian mother, father and child cohort

PURPOSE

To estimate the association between Attention-Deficit/Hyperactivity Disorder (ADHD) in children in preschool and primary school, and prenatal exposure to non-steroidal anti-inflammatory drugs (NSAIDs) by timing and duration.

METHODS

This study was based on the Norwegian Mother, Father and Child Cohort Study linked to the Medical Birth Registry of Norway, the Norwegian Patient Registry (NPR) and the Norwegian Prescription Database (NorPD). NSAID exposure was identified by maternal self-report in pregnancy. Child diagnosis of ADHD was obtained from NPR and NorPD. Symptoms of ADHD at age 5 years were measured using Conners' Parent Rating Scale-Revised, where higher scores correspond to more symptoms. To account for time-varying exposure and confounders, marginal structural models were fitted to estimate hazard ratios and mean difference in z-scores.

RESULTS

The analyses on ADHD diagnosis and ADHD symptoms included 56 340 and 34 961 children respectively. Children exposed to NSAIDs prenatally had no increased risk of ADHD diagnosis (first trimester: HR 1.12, 95% CI 0.86;1.45, second trimester: HR 0.98, 95% CI 0.69;1.38, third trimester: HR 0.68, 95% CI 0.31; 1.46) or ADHD symptoms (first trimester: standardized mean difference 0.03, 95% CI -0.03;0.09, second trimester: standardized mean difference 0.03, 95% CI -0.04;0.11, third trimester: standardized mean difference 0.11, 95% CI -0.03; 0.25). There was no duration-response relationship for either outcome.

CONCLUSION

Though non-differential misclassification of the exposure may have attenuated results, these findings are reassuring and suggest no substantially increased risk of ADHD diagnosis or symptoms in children prenatally exposed to NSAIDs, regardless of timing or duration.

Early exposure to paracetamol reduces level of testicular testosterone and changes gonadal expression of genes relevant for steroidogenesis in rats offspring

In this study, we investigated the effects of early paracetamol treatment on the testicular level of testosterone and expression of genes important for steroid biosynthesis and reproduction in male rats offspring. Rats were continuously exposed to paracetamol at doses of 5 or 15 mg/kg b.w. during pregnancy and the first two months of the postpartum development. Testosterone level was determined by ELISA. Profile of gene expression for the testicular steroidogenic factors were evaluated using the Real-Time PCR. Our results showed that paracetamol reduces testicular testosterone level and causes compensatory transactivation of genes important for steroidogenesis and reproductive capacity. We have observed significant over-expression of several genes involved in cholesterol transport and steroid biosynthesis e.g., genes for steroidogenic acute regulatory protein, hydroxysteroid dehydrogenases, luteinizing hormone subunit beta, gonadotropin and androgen receptors. Up-regulation of these genes with parallel testosterone reduction in the testicles could be the possible mechanism that maintains and prevents the loss of the steroidogenic function.

Intrauterine Exposure to Acetaminophen and Adverse Developmental Outcomes: Epidemiological Findings and Methodological Issues

PURPOSE OF REVIEW

Acetaminophen (or paracetamol) is one of the most commonly used medications during pregnancy. We reviewed recent epidemiological evidence regarding intrauterine exposure to acetaminophen and risk for asthma, neurodevelopment disorders, and reproductive health in childhood.

RECENT FINDINGS

An increasing number of cohort studies have suggested that maternal use of acetaminophen during pregnancy was associated with increased risk for asthma; neurodevelopmental disorders, especially ADHD and behavioral problems; and genital malformations in the offspring. Oxidative stress and inflammation or endocrine effects are plausible shared biological mechanisms for the exposure to influence multiple developmental outcomes. We discussed methodological challenges that can threaten the validity of these observational data, including confounding and measurement errors. Novel statistical methods and research designs that can be used to mitigate these issues were introduced. Given the high prevalence of use, findings regarding intrauterine exposure to acetaminophen on multiple child health outcomes raise concerns. Research on causal and non-causal mechanisms that might explain these associations should be a priority.

Demolition Activity and Elevated Blood Lead Levels among Children in Detroit, Michigan, 2014-2018

Older buildings in the United States often contain lead paint, and their demolition poses the risk of community lead exposure. We investigated associations between demolitions and elevated blood lead levels (EBLLs) among Detroit children aged <6 years, 2014-2018, and evaluated yearly variation given health and safety controls implemented during this time. Case-control analysis included incident EBLL cases (≥5 µg/dL) and non-EBLL controls from test results reported to the Michigan Department of Health and Human Services. Exposure was defined as the number of demolitions (0, 1, 2+) within 400 feet of the child's residence 45 days before the blood test. We used logistic regression to calculate odds ratios (ORs) and 95% confidence intervals (CIs), and test effect modification by year. Associations between demolition and EBLL differed yearly (p = 0.07): 2+ demolitions were associated with increased odds of EBLLs in 2014 (OR: 1.75; 95% CI: (1.17, 2.55), 2016 (2.36; 1.53, 3.55) and 2017 (2.16; 1.24, 3.60), but not in 2018 (0.94; 0.41, 1.86). This pattern remained consistent in sensitivity analyses. The null association in 2018 may be related to increased health and safety controls. Maintenance of controls and monitoring are essential, along with other interventions to minimize lead exposure, especially for susceptible populations.

Using negative control outcomes to assess the comparability of treatment groups among women with osteoporosis in the United States

PURPOSE

In contrast to randomized clinical trials, comparative safety and effectiveness assessments of osteoporosis medications in clinical practice may be subject to confounding by indication. We used negative control outcomes to detect residual confounding when comparing osteoporosis medications.

METHODS

Using MarketScan Commercial and Supplemental claims, we identified women aged ≥55 years who initiated an oral bisphosphonate (BP) (risedronate, alendronate, or ibandronate), denosumab (an injected biologic), or intravenous zoledronic acid (ZA) from October 1, 2010 to September 30, 2015. Women with Paget's disease or cancer were excluded. We compared individual oral BPs to each other, denosumab to ZA, denosumab to oral BPs, and ZA to oral BPs, with respect to 11 negative control outcomes identified by subject matter experts. We estimated the 12-month cumulative risk difference (RD) using inverse probability of treatment and censoring weights.

RESULTS

Among 148 587 women, most initiated alendronate (57%), followed by ibandronate (12%), ZA (11%), risedronate (10%), and denosumab (10%). Compared with denosumab, patients initiating ZA had similar risks of all negative control outcomes. Compared with oral BPs, patients initiating denosumab had a higher risk of a wellness visit (RD = 1.2%, 95% CI: 0.4, 1.9) and a lower risk of receiving herpes zoster vaccine (RD = -0.6%, 95% CI: -1.1, -0.2). Comparing ZA with oral BP initiators resulted in two outcomes with positive associations.

CONCLUSIONS

Caution is warranted when comparing injectable vs oral osteoporosis medications, given the potential for unmeasured confounding. Evaluating negative control outcomes could be a standard validity check prior to conducting comparative studies.

Maternal acetaminophen use during pregnancy and childhood behavioural problems: Discrepancies between mother- and teacher-reported outcomes

BACKGROUND

Maternal acetaminophen use during pregnancy is common and has been associated with childhood behavioural problems among offspring, specifically hyperactivity and conduct problems.

OBJECTIVE

Assessments of child behaviour in many previous studies have relied on maternal or parent report. Acknowledging that results of behavioural assessments vary between informants, we examined the association between maternal acetaminophen use during pregnancy and behaviour problems in childhood based on mother- and teacher-report.

METHODS

A longitudinal study of 560 mother-child pairs with data on illnesses and medication use during pregnancy and neurodevelopmental assessments during childhood was conducted. Acetaminophen use during pregnancy was captured using a standardised maternal interview, completed 1 year after delivery on average. Measures of childhood (6-12 years of age) behaviour were obtained via mother- and teacher-report, using the Child Behaviour Checklist and Teacher Report Form. Linear and log-binomial models were used to calculate adjusted mean differences (MD) and risk ratios (RR), respectively and 95% confidence intervals (CI) for internalising, externalising, and total behaviour problems comparing acetaminophen users to non-users. Stabilized inverse probability weights were used to account for loss to follow-up, and adjustments for indication were made.

RESULTS

Approximately 60% (n = 354) of women reported use of acetaminophen during pregnancy. Acetaminophen use during pregnancy was associated with an increase in total behaviour problem score and risk of clinical behaviour problems according to mother report (MD 2.2, 95% CI 0.3, 4.1 and RR 1.93, 95% CI 0.99, 3.76) but not according to teacher report. Weighting to account for participation did not alter results, while adjustment for indications of acetaminophen use greatly attenuated the associations with mother-reported total behaviour problem score and risk of clinical behaviour problems (MD 0.1, 95% CI -2.1, 2.3 and RR 1.31, 95% CI 0.67, 2.58).

CONCLUSIONS

Acetaminophen use during pregnancy was weakly associated with mother-reported behaviour problems and not associated with teacher-reported problems.

Acetaminophen use during pregnancy and the risk of attention deficit hyperactivity disorder: A causal association or bias?

BACKGROUND

The association between acetaminophen use during pregnancy and the development of attention deficit hyperactivity disorder (ADHD) in the offspring may be due to bias.

OBJECTIVES

The primary objective was to assess the role of potential unmeasured confounding in the estimation of the association between acetaminophen use during pregnancy and the risk of ADHD, through bias analysis. The secondary objective was to assess the roles of selection bias and exposure misclassification.

DATA SOURCES

We searched MEDLINE, Embase, Scopus, and the Cochrane Library up to December 2018.

STUDY SELECTION AND DATA EXTRACTION

We included observational studies examining the association between acetaminophen use during pregnancy and the risk of ADHD.

SYNTHESIS

We meta-analysed data across studies, using random-effects model. We conducted a bias analysis to studies that did not adjust for important confounders, to explore systematic errors related to unmeasured confounding, selection bias, and exposure misclassification.

RESULTS

The search resulted in seven studies included in our meta-analysis. When adjusted estimates were pooled across all studies, the risk ratio (RR) for ADHD was 1.35 (95% confidence interval [CI] 1.25, 1.46; I²  = 48%). Sensitivity analysis for unmeasured confounding in this meta-analysis showed that a confounder of 1.69 on the RR scale would reduce to 10% the proportion of studies with a true effect size of RR >1.10. Unmeasured confounding bias analysis decreased the point estimate in five of the seven studies and increased in two studies, suggesting that the observed association could be confounded by parental ADHD. Unadjusted and bias-corrected risk ratios (bcRRs) were: RR = 1.34, bcRR = 1.13; RR = 1.51, bcRR = 1.17; RR = 1.63, bcRR = 1.38; RR = 1.44, bcRR = 1.17; RR = 1.16, bcRR = 1.18; RR = 1.25, bcRR = 1.05; and RR = 0.99, bcRR = 1.18.

CONCLUSIONS

Bias analysis suggests that the previously reported association between acetaminophen use during pregnancy and an increased risk of ADHD in the offspring may be due to unmeasured confounding. Our ability to conclude a causal association is limited.

Associations of acetaminophen use during pregnancy and the first year of life with neurodevelopment in early childhood

BACKGROUND

Over-the-counter analgesic use during pregnancy, particularly acetaminophen, may be associated with negative developmental outcomes in children.

OBJECTIVE

Estimate associations of prenatal and early-life exposure to acetaminophen in early childhood with cognitive, motor, and language skills in two birth cohorts.

METHODS

The American Project Viva cohort (1217 mother-child pairs enrolled 1999-2002) assessed cognition at approximately 3 years using the Peabody Picture Vocabulary Test and the Wide Range Achievement of Visual Motor Abilities (WRAVMA). The Brazilian 2015 Pelotas Birth Cohort (3818 mother-child pairs) assessed cognition at 2 years using the INTERGROWTH-21st Neurodevelopment Assessment. We used linear regression to estimate associations of acetaminophen use during pregnancy (Project Viva and Pelotas) and infancy (Project Viva) with children's cognitive scores adjusted for maternal age, pre-pregnancy body mass index, education, parity, race/ethnicity, smoking and alcohol use during pregnancy, depression during pregnancy, antibiotic and ibuprofen use during pregnancy, household income, and child's sex.

RESULTS

In Project Viva, exposure to acetaminophen in both the 1st and 2nd trimester of pregnancy was associated with lower WRAVMA drawing scores (β -1.51, 95% CI -2.92, -0.10). However, in Pelotas, exposure to acetaminophen in both the 1st and 2nd trimester of pregnancy was not associated with INTER-NDA motor scores (β 0.02; 95% CI -0.05, 0.09) and was associated with higher INTER-NDA total scores (β 0.08, 95% CI 0.01, 0.16). Other comparisons did not show evidence for any associations.

CONCLUSIONS

Inconsistencies and lack of specificity of the findings did not clarify the research question considering that we still have a large variability and uncertainty to define the risk or safety in the use of acetaminophen related to cognition in early childhood. More studies using better exposure assessment and better confounding variables are needed to clarify these associations.

Associations of prenatal or infant exposure to acetaminophen or ibuprofen with mid-childhood executive function and behaviour

BACKGROUND

Over-the-counter analgesics during pregnancy or infancy may be related to neurobehavioural problems in children, but little is known about effects of different analgesic types, dosage, and timing.

OBJECTIVES

Examine associations of acetaminophen and ibuprofen use during pregnancy and infancy with executive function and behaviour problems in children.

METHODS

We included 1225 mother-child pairs from Project Viva, a pre-birth cohort study. We assessed prenatal acetaminophen and ibuprofen use in early and mid-pregnancy and infant use in the first year of life using questionnaires. Parents and classroom teachers assessed child behaviours in mid-childhood (median 8 years), using the Behavior Rating Inventory of Executive Function (BRIEF) and the Strengths and Difficulties Questionnaire (SDQ), with higher scores indicating worse functioning for both. We examined associations of acetaminophen and ibuprofen use during pregnancy and infancy with mid-childhood neurobehavioural outcomes using linear regression models adjusted for potential confounders.

RESULTS

During pregnancy, 46.1% of mothers used acetaminophen ≥10 times and 18.4% used any ibuprofen. In the first year, 65.3% and 39.6% of infants received acetaminophen and ibuprofen ≥6 times, respectively. Higher (≥10 vs <10 times) prenatal acetaminophen (β 1.64 points; 95% confidence interval [CI] 0.59, 2.68) and any ibuprofen (β 1.56, 95% CI 0.19, 2.92) were associated with higher parent-rated BRIEF global scores. Patterns of association were linear across categories and were similar for other parent- and teacher-rated outcomes. Infancy exposure (≥6 vs <6 times) to acetaminophen (β 1.69, 95% CI 0.51, 2.87) and ibuprofen (β 1.40, 95% CI 0.25, 2.55) were associated with higher parent-rated BRIEF GEC scores but associations with teacher-rated scores were weaker.

CONCLUSIONS

Prenatal and early-life exposure to acetaminophen and ibuprofen were associated with poorer executive function and behaviour in childhood. These findings highlight the need for further research on the mechanisms through which analgesics may act on fetal and child brain development.

Invited Commentary: The Disillusionment of Developmental Origins of Health and Disease (DOHaD) Epidemiology

The developmental origins of health and disease (DOHaD) model promises a greater understanding of early development but has left unresolved the balance of risks and benefits to offspring of medication use during pregnancy. Masarwa et al. (Am J Epidemiol. 2018;187(8):1817-1827) conducted a meta-analysis of the association between in utero acetaminophen exposure and risks of attention deficit hyperactivity disorder (ADHD) and autism spectrum disorder (ASD). A challenge of meta-analyzing results from observational studies is that summary measures of risk do not correspond to well-defined interventions when the individual studies adjusted for different covariate sets, which was the case here. This challenge limits the usefulness of observational meta-analyses for inferences about etiology and treatment planning. With that limitation understood, Masarwa et al. reported a 20%-30% higher risk of ADHD and ASD following prenatal acetaminophen exposure. Surprisingly, most of the original studies did not report diagnoses of ADHD or ASD. As a result, their summary estimates of risk are not informative about children's likelihood of ADHD and ASD diagnoses. The long-term promise of DOHaD remains hopeful, but more effort is needed in the short-term to critically evaluate observational studies suggesting risks associated with medications used to treat conditions during pregnancy that might have adverse consequences for a developing fetus.

Use and validity of child neurodevelopment outcome measures in studies on prenatal exposure to psychotropic and analgesic medications - A systematic review

In recent years there has been increased attention to child neurodevelopment in studies on medication safety in pregnancy. Neurodevelopment is a multifactorial outcome that can be assessed by various assessors, using different measures. This has given rise to a debate on the validity of various measures of neurodevelopment. The aim of this review was twofold. Firstly we aimed to give an overview of studies on child neurodevelopment after prenatal exposure to central nervous system acting medications using psychotropics and analgesics as examples, giving special focus on the use and validity of outcome measures. Secondly, we aimed to give guidance on how to conduct and interpret medication safety studies with neurodevelopment outcomes. We conducted a systematic review in the MEDLINE, Embase, PsycINFO, Web of Science, Scopus, and Cochrane databases from inception to April 2019, including controlled studies on prenatal exposure to psychotropics or analgesics and child neurodevelopment, measured with standardised psychometric instruments or by diagnosis of neurodevelopmental disorder. The review management tool Covidence was used for data-extraction. Outcomes were grouped as motor skills, cognition, behaviour, emotionality, or "other". We identified 110 eligible papers (psychotropics, 82 papers, analgesics, 29 papers). A variety of neurodevelopmental outcome measures were used, including 27 different psychometric instruments administered by health care professionals, 15 different instruments completed by parents, and 13 different diagnostic categories. In 23 papers, no comments were made on the validity of the outcome measure. In conclusion, establishing neurodevelopmental safety includes assessing a wide variety of outcomes important for the child's daily functioning including motor skills, cognition, behaviour, and emotionality, with valid and reliable measures from infancy through to adolescence. Consensus is needed in the scientific community on how neurodevelopment should be assessed in medication safety in pregnancy studies. Review registration number: CRD42018086101 in the PROSPERO database.