Multiple Job Holding, Job Changes, and Associations with Gestational Diabetes and Pregnancy-Related Hypertension in the National Birth Defects Prevention Study.

We used National Birth Defects Prevention Study data to investigate associations between working patterns shortly before and during pregnancy and gestational diabetes and pregnancy-related hypertension. We analyzed working patterns (multiple-job holders, job changers, single-job holders) during the three months before and during pregnancy for 8140 participants who delivered a live-born child without a birth defect. "Multiple-job holders" worked more than one job simultaneously, "job changers" worked more than one job with no overlap, and "single-job holders" (referent) worked one job. We used multivariable logistic regression to estimate associations between working pattern and each outcome, adjusting for maternal age and educational attainment at delivery. We explored effect measure modification by household income, peak weekly working hours, and maternal race/ethnicity. Multiple-job holders had higher odds of gestational diabetes (adjusted odds ratio [aOR]: 1.5; 95% confidence interval [CI]: 1.1-2.1) and pregnancy-related hypertension (aOR: 1.5; 95% CI: 1.0-2.2) compared with single-job holders. Multiple-job holders with a household income of more than 30,000 USD per year, 32-44 peak weekly working hours, and from racial/ethnic minority groups had higher odds of gestational diabetes compared with single-job holders in respective categories. Detailed occupational information is important for studies of occupation and maternal health.

Occupational physical demands and menstrual cycle irregularities in flight attendants and teachers.

OBJECTIVES: Flight attendants perform physically demanding work such as lifting baggage, pushing service carts and spending the workday on their feet. We examined if more frequent exposure to occupational physical demands could explain why previous studies have found that flight attendants have a higher reported prevalence of menstrual cycle irregularities than other workers. METHODS: We conducted a cross-sectional analysis of 694 flight attendants and 120 teachers aged 18-44 years from three US cities. Eligible participants were married, had not had a hysterectomy or tubal ligation, were not using hormonal contraception and were not recently pregnant. Participants reported menstrual cycle characteristics (cramps, pain, irregular cycles, flow, bleed length, cycle length) and occupational physical demands (standing, lifting, pushing/pulling, bending/twisting, overall effort). We used modified Poisson regression to examine associations between occupation (flight attendant, teacher) and menstrual irregularities; among flight attendants, we further examined associations between occupational physical demands and menstrual irregularities. RESULTS: All occupational physical demands were more commonly reported by flight attendants than teachers. Flight attendants reported more frequent menstrual cramps than teachers, and most occupational physical demands were associated with more frequent or painful menstrual cramps. Lifting heavy loads was also associated with irregular cycles. CONCLUSIONS: Occupational physical demands were associated with more frequent and worse menstrual pain among flight attendants. The physical demands experienced by these workers may contribute to the high burden of menstrual irregularities reported by flight attendants compared with other occupational groups, such as teachers.

Maternal occupational exposure to selected organic and chlorinated solvents and delivery of small-for-gestational age or preterm infants.

BACKGROUND: Potential reproductive effects of organic solvent exposure during pregnancy remain unclear. We investigated the association between maternal occupational exposure during pregnancy to six chlorinated solvents, three aromatic solvents, and Stoddard solvent, and delivery of preterm infants or those born small-for-gestational age (SGA). METHODS: In this case-control study of SGA and preterm birth (PTB) nested within the National Birth Defects Prevention Study (NBDPS) from 1997 to 2011, we analyzed data from 7504 singleton live births without major birth defects and their mothers. Self-reported information on jobs held in the periconceptional period was assessed for solvent exposure. Unconditional logistic regression was used to estimate the association between maternal occupational exposure (any, none) during early pregnancy to organic solvents and PTB and SGA. Linear regression was used to examine changes in mean birthweight potentially associated with maternal occupational solvent exposure. RESULTS: Maternal occupational exposure to any organic solvents overall was not associated with an increased odds of PTB (adjusted odds ratio [aOR] = 0.94; 95% confidence interval [CI] 0.67-1.33) or SGA (aOR = 0.93; 95% CI 0.65-1.34). Point estimates increased modestly for higher estimated exposure versus lower, but confidence intervals were wide and not statistically significant. Maternal exposure to solvents was not associated with a statistically significant change in term birthweight among infants. CONCLUSIONS: Occupational exposure to organic solvents at the frequency and intensity levels found in a population-based sample of pregnant workers was not associated with PTB or SGA; however, we cannot rule out any effects among pregnant workers with uncommonly high exposure to organic solvents.

Birth defects associated with paternal firefighting in the National Birth Defects Prevention Study.

BACKGROUND: Few studies have evaluated birth defects among children of firefighters. We investigated associations between birth defects and paternal work as a firefighter compared to work in non-firefighting and police officer occupations. METHODS: We analyzed 1997-2011 data from the multi-site case-control National Birth Defects Prevention Study. Cases included fetuses or infants with major structural birth defects and controls included a random sample of live-born infants without major birth defects. Mothers of infants self-reported information about parents' occupations held during pregnancy. We investigated associations between paternal firefighting and birth defect groups using logistic regression to estimate odds ratios (ORs) and 95% confidence intervals (CIs). Referent groups included families reporting fathers working non-firefighting and police officer jobs. RESULTS: Occupational groups included 227 firefighters, 36,285 non-firefighters, and 433 police officers. Twenty-nine birth defects were analyzed. In adjusted analyses, fathers of children with total anomalous pulmonary venous return (TAPVR; OR = 3.1; 95% CI = 1.1-8.7), cleft palate (OR = 1.8; 95% CI = 1.0-3.3), cleft lip (OR = 2.2; 95% CI = 1.2-4.2), and transverse limb deficiency (OR = 2.2; 95% CI = 1.1-4.7) were more likely than fathers of controls to be firefighters, versus non-firefighters. In police-referent analyses, fathers of children with cleft palate were 2.4 times more likely to be firefighters than fathers of controls (95% CI = 1.1-5.4). CONCLUSIONS: Paternal firefighting may be associated with an elevated risk of birth defects in offspring. Additional studies are warranted to replicate these findings. Further research may contribute to a greater understanding of the reproductive health of firefighters and their families for guiding workplace practices.

Occurrences of Workplace Violence Related to the COVID-19 Pandemic, United States, March 2020 to August 2021.

As businesses dealt with an increasingly anxious public during the COVID-19 pandemic and were frequently tasked with enforcing various COVID-19 prevention policies such as mask mandates, workplace violence and harassment (WPV) emerged as an increasing important issue affecting worker safety and health. Publicly available media reports were searched for WPV events related to the COVID-19 pandemic that occurred during 1 March 2020, and 31 August 2021, using Google News aggregator services scans with data abstraction and verification. The search found 408 unique WPV events related to COVID-19. Almost two-thirds involved mask disputes. Over half (57%) of the 408 events occurred in retail (38%) and food service (19%). We also conducted a comparison of events identified in this search to a similar study of media reports between March 2020 to October 2020 that used multiple search engines to identify WPV events. Despite similar conclusions, a one-to-one comparison of relevant data from these studies found only modest overlap in the incidents identified, suggesting the need to make improvements to future efforts to extract data from media reports. Prevention resources such as training and education for workers may help industries de-escalate or prevent similar WPV events in the future.

COVID-19 Vaccine Uptake and Factors Affecting Hesitancy Among US Nurses, March-June 2021.

Objectives. To characterize COVID-19 vaccine uptake and hesitancy among US nurses. Methods. We surveyed nurses in 3 national cohorts during spring 2021. Participants who indicated that they did not plan to receive or were unsure whether they planned to receive the vaccine were considered vaccine hesitant. Results. Among 32 426 female current and former nurses, 93% had been or planned to be vaccinated. After adjustment for age, race/ethnicity, and occupational variables, vaccine hesitancy was associated with lower education, living in the South, and working in a group care or home health setting. Those who experienced COVID-19 deaths and those reporting personal or household vulnerability to COVID-19 were less likely to be hesitant. Having contracted COVID-19 doubled the risk of vaccine hesitancy (95% confidence interval [CI] = 1.85, 2.53). Reasons for hesitancy that were common among nurses who did not plan to receive the vaccine were religion/ethics, belief that the vaccine was ineffective, and lack of concern about COVID-19; those who were unsure often cited concerns regarding side effects or medical reasons or reported that they had had COVID-19. Conclusions. Vaccine hesitancy was unusual and stemmed from specific concerns. Public Health Implications. Targeted messaging and outreach might reduce vaccine hesitancy. (Am J Public Health. 2022;112(11):1620-1629. https://doi.org/10.2105/AJPH.2022.307050).

Maternal occupation as a nail technician or hairdresser during pregnancy and birth defects, National Birth Defects Prevention Study, 1997-2011.

OBJECTIVE: Nail technicians and hairdressers may be exposed to chemicals with potential reproductive effects. While studies have examined birth defects in children of hairdressers, those in children of nail technicians have not been evaluated. We investigated associations between selected birth defects and maternal occupation as a nail technician or hairdresser versus a non-cosmetology occupation during pregnancy. METHODS: We analysed population-based case-control data from the multisite National Birth Defects Prevention Study, 1997-2011. Cases were fetuses or infants with major structural birth defects; controls were live-born infants without major birth defects. Expert raters classified self-reported maternal jobs as nail technician, combination nail technician-hairdresser, hairdresser, other cosmetology work or non-cosmetology work. We used logistic regression to calculate adjusted ORs and 95% CIs for associations between occupation during pregnancy and birth defects, controlling for age, smoking, education and race/ethnicity. RESULTS: Sixty-one mothers worked as nail technicians, 196 as hairdressers, 39 as combination nail technician-hairdressers and 42 810 as non-cosmetologists. The strongest associations among nail technicians included seven congenital heart defect (CHD) groups (ORs ranging from 2.7 to 3.5) and neural tube defects (OR=2.6, CI=0.8 to 8.4). Birth defects most strongly associated with hairdressing included anotia/microtia (OR=2.1, CI=0.6 to 6.9) and cleft lip with cleft palate (OR=2.0, CI=1.1 to 3.7). All oral cleft groups were associated with combination nail technician-hairdresser work (ORs ranging from 4.2 to 5.3). CONCLUSIONS: Small samples resulted in wide CIs. Still, results suggest associations between maternal nail technician work during pregnancy and CHDs and between hairdressing work and oral clefts.

Characteristics of Women with Urinary Tract Infection in Pregnancy.

Background: Urinary tract infection (UTI) is the most common bacterial infection in pregnancy. Known risk factors for UTI in pregnancy include diabetes and certain urologic conditions. Other maternal characteristics might also be associated with risk and could provide clues to the etiology of UTI in pregnancy. Our objective was to identify maternal characteristics associated with UTI in pregnancy. Materials and Methods: We used data from pregnant women participating in the National Birth Defects Prevention Study, a population-based study of risk factors for major structural birth defects in 10 U.S. sites, from 1997 to 2011. In cross-sectional analyses, we used multivariable log-binomial regression to estimate prevalence ratios (PRs) and 95% confidence intervals (CIs) for associations between self-reported maternal characteristics and UTI in pregnancy. Results: In our sample of 41,869 women, the overall prevalence of reported UTI in pregnancy was 18%, but ranged from 11% to 26% between study sites. In adjusted models, diabetes was moderately associated with higher UTI prevalence (PR 1.39, 95% CI: 1.24-1.57). Higher UTI prevalence was associated even more strongly with low educational attainment (PR 2.06, 95% CI: 1.77-2.40 for some high school vs. graduate school), low household income (PR 1.64, 95% CI: 1.46-1.84 for <$10,000 vs. ≥$50,000), and race/ethnicity (PR 1.45, 95% CI: 1.13-1.80 for American Indian or Alaska Native vs. White women). Conclusions: About one in six women reported UTI in pregnancy but the prevalence varied markedly by geography and maternal characteristics. This variability could provide clues to the causes of UTI in pregnancy.

American Frontline Healthcare Personnel's Access to and Use of Personal Protective Equipment Early in the COVID-19 Pandemic.

OBJECTIVES: To quantify adequacy of personal protective equipment (PPE) for U.S. healthcare personnel (HCP) at the outset of the COVID-19 pandemic and its association with infection risk. METHODS: March-May 2020 survey of the national Nurses' Health Studies and the Growing Up Today study regarding self-reported PPE access, use, and reuse. COVID-19 endpoints included SARS-CoV-2 tests and COVID-19 status predicted from symptoms. RESULTS: Nearly 22% of 22,232 frontline HCP interacting with COVID-19 patients reported sometimes or always lacking PPE. Fifty percent of HCP reported not needing respirators, including 13% of those working in COVID-19 units. Lack of PPE was cross-sectionally associated with two-fold or greater odds of COVID-19 among those who interacted with infected patients. CONCLUSION: These data show the need to improve the U.S. infection prevention culture of safety when confronting a novel pathogen.

Testing and Validating Semi-automated Approaches to the Occupational Exposure Assessment of Polycyclic Aromatic Hydrocarbons.

INTRODUCTION: When it is not possible to capture direct measures of occupational exposure or conduct biomonitoring, retrospective exposure assessment methods are often used. Among the common retrospective assessment methods, assigning exposure estimates by multiple expert rater review of detailed job descriptions is typically the most valid, but also the most time-consuming and expensive. Development of screening protocols to prioritize a subset of jobs for expert rater review can reduce the exposure assessment cost and time requirement, but there is often little data with which to evaluate different screening approaches. We used existing job-by-job exposure assessment data (assigned by consensus between multiple expert raters) from a large, population-based study of women to create and test screening algorithms for polycyclic aromatic hydrocarbons (PAHs) that would be suitable for use in other population-based studies. METHODS: We evaluated three approaches to creating a screening algorithm: a machine-learning algorithm, a set of a priori decision rules created by experts based on features (such as keywords) found in the job description, and a hybrid algorithm incorporating both sets of criteria. All coded jobs held by mothers of infants participating in National Birth Defects Prevention Study (NBDPS) (n = 35,424) were used in developing or testing the screening algorithms. The job narrative fields considered for all approaches included job title, type of product made by the company, main activities or duties, and chemicals or substances handled. Each screening approach was evaluated against the consensus rating of two or more expert raters. RESULTS: The machine-learning algorithm considered over 30,000 keywords and industry/occupation codes (separate and in combination). Overall, the hybrid method had a similar sensitivity (87.1%) as the expert decision rules (85.5%) but was higher than the machine-learning algorithm (67.7%). Specificity was best in the machine-learning algorithm (98.1%), compared to the expert decision rules (89.2%) and hybrid approach (89.1%). Using different probability cutoffs in the hybrid approach resulted in improvements in sensitivity (24-30%), without the loss of much specificity (7-18%). CONCLUSION: Both expert decision rules and the machine-learning algorithm performed reasonably well in identifying the majority of jobs with potential exposure to PAHs. The hybrid screening approach demonstrated that by reviewing approximately 20% of the total jobs, it could identify 87% of all jobs exposed to PAHs; sensitivity could be further increased, albeit with a decrease in specificity, by adjusting the algorithm. The resulting screening algorithm could be applied to other population-based studies of women. The process of developing the algorithm also provides a useful illustration of the strengths and potential pitfalls of these approaches to developing exposure assessment algorithms.

Prepregnancy handling of antineoplastic drugs and risk of miscarriage in female nurses.

PURPOSE: To examine the association betweenantineoplastic drug (AD) handling and risk of miscarriage. METHODS: Nurses' Health Study-3 participants self-reported AD administration and engineering controls (ECs) and personal protective equipment (PPE) use at baseline. We estimated the hazard ratio (HR) of miscarriage in relation to baseline AD handling using multivariable Cox proportional regression. RESULTS: Overall, 2440 nurses reported 3327 pregnancies, with 550 (17%) ended in miscarriages. Twelve percent of nurses self-reported currently handling AD and 28% previously handling AD. Compared with nurses who never handled AD, nurses who handled AD at baseline had an adjusted HR of miscarriage of 1.26 (95% confidence interval [CI], 0.97-1.64). This association was stronger after 12-weeks gestation (HR=2.39 [95% CI, 1.13-5.07]). Nurses who did not always use gloves had HR of 1.51 (95% CI, 0.91-2.51) compared with 1.19 (95% CI, 0.89-1.60) for those always using gloves; nurses who did not always use gowns had HR of 1.32 (95% CI, 0.95-1.83) compared with 1.19 (95% CI, 0.81-1.75) for nurses always using gowns. CONCLUSIONS: We observed a suggestive association between AD handling and miscarriage, particularly among nurses who did not consistently use PPE and EC with stronger associations for second trimester losses.

Maternal occupational exposure to polycyclic aromatic hydrocarbons and the risk of isolated congenital heart defects among offspring.

BACKGROUND: Although there is evidence in experimental model systems that exposure to polycyclic aromatic hydrocarbons (PAHs) is linked with congenital heart defects (CHDs), few studies have examined the association in humans. We conducted a case-control study to examine the association between maternal exposure to PAHs and CHDs in offspring using data from the National Birth Defects Prevention Study (NBDPS) (1997-2011). METHODS: We obtained detailed information on maternal occupation during the month before to three months after conception. Expert raters, masked to case-control status, assessed job descriptions to assign categorical levels of exposure. Categories were quantitatively mapped to estimate cumulative exposure to PAHs, incorporating exposure intensity, frequency, work duration, and work hours. Quartiles were generated for cumulative maternal exposure to PAHs. Crude and adjusted odds ratios (ORs) with 95% confidence intervals (CIs) were estimated using unconditional logistic regression for quartiles of PAH exposure and six CHD groupings (e.g. conotruncal) and specific subtypes (e.g. tetralogy of Fallot [ToF]). Final models were adjusted for maternal age, race/ethnicity, education, smoking, anticonvulsant use, folic acid supplementation, and study center. RESULTS: There were 4,775 case and 7,734 control infants eligible for the study. The prevalence of occupational exposure to PAHs was 10.2% among both case and control mothers. In adjusted analysis, compared to mothers with no occupational PAH exposure, those in the highest quartile of exposure were more likely to have offspring in the conotruncal heart defects group (OR 1.41; 95% CI 1.00-2.00), and with ToF (OR 1.83; 95% CI 1.21-2.78). CONCLUSIONS: Women in the highest quartile of estimated cumulative occupational PAH exposure during early pregnancy were more likely to have offspring with conotruncal heart defects, specifically ToF, compared to women with no occupational PAH exposure. Other comparisons between PAHs and other CHDs subgroups did not show any statistically precise associations.

Association between maternal occupational exposure to polycyclic aromatic hydrocarbons and rare birth defects of the face and central nervous system.

BACKGROUND: Previous studies suggested associations between maternal smoking, a source of exposure to polycyclic aromatic hydrocarbons (PAHs) and other chemicals, and central nervous system and face birth defects; however, no previous studies have evaluated maternal occupational PAH exposure itself. METHODS: Jobs held in the periconceptional period were retrospectively assigned for occupational PAH exposures. Associations between maternal occupational PAH exposure and selected rare defects of the face (cataracts, microphthalmia, glaucoma, microtia, and choanal atresia) and central nervous system (holoprosencephaly, hydrocephaly, cerebellar hypoplasia, and Dandy-Walker malformation) were evaluated using data from the National Birth Defects Prevention Study, a population-based case-control study in the United States. Crude and adjusted odds ratios (ORs) with 95% confidence intervals were calculated to estimate associations between each evaluated defect and PAH exposure using multivariable logistic regression. RESULTS: Food and beverage serving, as well as cooks and food preparation occupations, were among the most frequent jobs held by exposed mothers. Cataracts, microtia, microphthalmia, and holoprosencephaly were significantly associated with PAH exposure with evidence of dose-response (P-values for trend ≤.05). Hydrocephaly was associated with any PAH exposure, but not significant for trend. Sensitivity analyses that reduced possible sources of exposure misclassification tended to strengthen associations. CONCLUSIONS: This is the first population-based case-control study to evaluate associations between maternal occupational PAH exposures and these rare birth defects of the central nervous system and face.

Maternal Occupational Oil Mist Exposure and Birth Defects, National Birth Defects Prevention Study, 1997⁻2011.

Workers in various industries can be exposed to oil mists when oil-based fluids are aerosolized during work processes. Oil mists can be inhaled or deposited on the skin. Little research exists on the reproductive effects of oil mist exposure in pregnant workers. We aimed to investigate associations between occupational oil mist exposure in early pregnancy and a spectrum of birth defects using data from 22,011 case mothers and 8140 control mothers in the National Birth Defects Prevention Study. In total, 150 mothers were rated as exposed. Manufacturing jobs, particularly apparel manufacturing, comprised the largest groups of exposed mothers. Mothers of infants with septal heart defects (odds ratio (OR): 1.8, 95% confidence interval (CI): 1.0-3.3), and especially perimembranous ventricular septal defects (OR: 2.5, CI: 1.2-5.2), were more likely to be occupationally exposed to oil mists in early pregnancy than control mothers; and their rater-estimated cumulative exposure was more likely to be higher. This was the first U.S. study evaluating associations between oil mist exposure and a broad spectrum of birth defects. Our results are consistent with previous European studies, supporting a potential association between oil-based exposures and congenital heart defects. Further research is needed to evaluate the reproductive effects of occupational oil mist exposure.

CE: Original Research: Antineoplastic Drug Administration by Pregnant and Nonpregnant Nurses: An Exploration of the Use of Protective Gloves and Gowns.

: Background: Many antineoplastic (chemotherapeutic) drugs are known or probable human carcinogens, and many have been shown to be reproductive toxicants in cancer patients. Evidence from occupational exposure studies suggests that health care workers who have long-term, low-level occupational exposure to antineoplastic drugs have an increased risk of adverse reproductive outcomes. It's recommended that, at minimum, nurses who handle or administer such drugs should wear double gloves and a nonabsorbent gown to protect themselves. But it's unclear to what extent nurses do. PURPOSE: This study assessed glove and gown use by female pregnant and nonpregnant nurses who administer antineoplastic drugs in the United States and Canada. METHODS: We used data collected from more than 40,000 nurses participating in the Nurses' Health Study 3. The use of gloves and gowns and administration of antineoplastic drugs within the past month (among nonpregnant nurses) or within the first 20 weeks of pregnancy (among pregnant nurses) were self-reported via questionnaire. RESULTS: Administration of antineoplastic drugs at any time during their career was reported by 36% of nonpregnant nurses, including 27% who reported administering these drugs within the past month. Seven percent of pregnant nurses reported administering antineoplastic drugs during the first 20 weeks of pregnancy. Twelve percent of nonpregnant nurses and 9% of pregnant nurses indicated that they never wore gloves when administering antineoplastic drugs, and 42% of nonpregnant nurses and 38% of pregnant nurses reported never using a gown. The percentage of nonpregnant nurses who reported not wearing gloves varied by type of administration: 32% of those who administered antineoplastic drugs only as crushed pills never wore gloves, compared with 5% of those who administered such drugs only via infusion. CONCLUSION: Despite longstanding recommendations for the safe handling of antineoplastic and other hazardous drugs, many nurses-including those who are pregnant-reported not wearing protective gloves and gowns, which are considered the minimum protective equipment when administering such drugs. These findings underscore the need for further education and training to ensure that both employers and nurses understand the risks involved and know which precautionary measures will minimize such exposures.

Structure and Control of Healthy Worker Effects in Studies of Pregnancy Outcomes.

Much of the literature on the healthy worker effect focuses on studies of chronic disease and mortality; however, when studying pregnancy outcomes, these effects might differ because of the short, defined risk periods of most pregnancy outcomes. Three pregnancy-specific healthy worker effects have also been described, but the structure of these effects has not yet been investigated when occupational exposure, and not employment status, is the exposure of interest. We used directed acyclic graphs to examine healthy worker effects in studies of occupational exposures and pregnancy outcomes: the healthy hire effect, the healthy worker survivor effect, the desperation/privilege effect (differential workforce reentry after pregnancy), the reproductively unhealthy worker effect (women with live births leave the workforce, while women with nonlive births do not), and the insecure pregnancy effect (women with adverse pregnancy outcomes reduce their exposures in subsequent pregnancies). Given our assumptions, we conclude that the healthy hire effect, the desperation/privilege effect, the reproductively unhealthy worker effect, and the insecure pregnancy effect result from confounding that can be addressed if data on measured confounders, such as employment status, are available. The presence of the healthy worker survivor effect, however, varies by study design. Different types of healthy worker effects can be present in studies of occupational exposure and pregnancy outcomes, and many of them are easily addressed analytically.

Maternal occupational cadmium exposure and nonsyndromic orofacial clefts.

BACKGROUND: Cigarette smoking is a well-studied risk factor for orofacial clefts (OFCs). Little is known about which constituents in cigarette smoke contribute to this teratogenicity in humans. One constituent, cadmium, has been associated with OFCs in animal studies; in humans, the role of maternal cadmium exposure on OFCs, independent of cigarette smoke, is unclear. In particular, the relation between maternal occupational cadmium exposure and OFCs is largely unexplored. METHODS: Using data from a large, population-based case-control study, we compared expert rater assessed maternal occupational cadmium exposure from self-reported occupational histories during the period 1 month before through 3 months after conception between OFC cases (n = 1,185) and unaffected controls (n = 2,832). Multivariable logistic regression analyses were used to estimate adjusted odds ratios (aORs) and 95% confidence intervals for any (yes/no) and cumulative (no, low, high exposure) occupational cadmium exposures and all OFCs, cleft lip ± cleft palate (CL/P) and cleft palate (CP). RESULTS: Overall, 45 mothers (cases = 13, controls = 32) were rated as having occupational cadmium exposure. Comparing all OFCs to controls, we observed inverse, nonsignificant aORs for any or low exposure, and positive, nonsignificant aORs for high exposure. Where data were available, aORs for CL/P and CP tended to parallel those for all OFCs. CONCLUSION: To our knowledge, this is the first study to specifically examine maternal occupational cadmium exposure and OFCs, using expert rater exposure assessment. The small numbers of exposed mothers observed, however, led to imprecise estimates. Continued research using more detailed occupational exposure assessment and increased sample sizes is recommended.

Factors affecting workforce participation and healthy worker biases in U.S. women and men.

PURPOSE: To investigate potential attenuation of healthy worker biases in populations in which healthy women of reproductive age opt out of the workforce to provide childcare. METHODS: We used 2013-2015 data from 120,928 U.S. women and men aged 22-44 years participating in the Gallup-Healthways Well-Being Index. We used logistic regression to estimate adjusted prevalence odds ratios (PORs) and 95% confidence intervals (CIs) for associations between health and workforce nonparticipation. RESULTS: Women and men reporting poor health were more likely to be out of the workforce than individuals reporting excellent health (POR: 3.7, 95% CI: 3.2-4.2; POR: 6.7, 95% CI: 5.7-7.8, respectively), suggesting potential for healthy worker bias. For women (P < .001) but not men (P = .30), the strength of this association was modified by number of children in the home: POR: 7.3 (95% CI: 5.8-9.1) for women with no children, decreasing to POR: 0.9 (95% CI: 0.6-1.5) for women with four or more children. CONCLUSIONS: These results are consistent with attenuation of healthy worker biases when healthy women opt out of the workforce to provide childcare. Accordingly, we might expect the magnitude of these biases to vary with the proportion of women with differing numbers of children in the population.

Agreement between two methods for retrospective assessment of occupational exposure intensity to six chlorinated solvents: Data from The National Birth Defects Prevention Study.

The wide variety of jobs encountered in population-based studies makes retrospective exposure assessment challenging in occupational epidemiology. In this analysis, two methods for estimating exposure intensity to chlorinated solvents are compared: rated (assigned by an expert rater) and modeled (assigned using statistical models). Estimates of rated and modeled intensities were compared for jobs held by mothers participating in the National Birth Defects Prevention Study with possible exposure to six chlorinated solvents: carbon tetrachloride, chloroform, methylene chloride, perchloroethylene, 1,1,1-trichloroethane, and trichloroethylene. For each possibly exposed job, an industrial hygienist assigned (1) an exposure intensity (rated intensity) and (2) determinants of exposure to be used in a statistical model of exposure intensity (modeled intensity). Of 12,326 reported jobs, between 31 (0.3%) and 746 (6%) jobs were rated as possibly exposed to each of the six solvents. Agreement between rated and modeled intensities was low overall (Spearman correlation coefficient range: -0.09 to 0.28; kappa range: -0.23 to 0.43). Although no air measurements were available to determine if rated or modeled estimates were more accurate, review of participants' job titles showed that modeled estimates were often unexpectedly high given the low-exposure tasks found in these jobs. Differences between the high-exposure jobs used to create the statistical models (obtained from air measurements in the published literature) and the low-exposure jobs in the actual study population is a potential explanation for the disagreement between the two methods. Investigators should be aware that statistical models estimating exposure intensity using existing data from one type of worker population might not be generalizable to all populations of workers.

Factors associated with employment status before and during pregnancy: Implications for studies of pregnancy outcomes.

BACKGROUND: Potential confounding or effect modification by employment status is frequently overlooked in pregnancy outcome studies. METHODS: To characterize how employed and non-employed women differ, we compared demographics, behaviors, and reproductive histories by maternal employment status for 8,343 mothers of control (non-malformed) infants in the National Birth Defects Prevention Study (1997-2007) and developed a multivariable model for employment status anytime during pregnancy and the 3 months before conception. RESULTS: Sixteen factors were independently associated with employment before or during pregnancy, including: maternal age, pre-pregnancy body mass index, pregnancy intention, periconceptional/first trimester smoking and alcohol consumption, and household income. CONCLUSIONS: Employment status was significantly associated with many common risk factors for adverse pregnancy outcomes. Pregnancy outcome studies should consider adjustment or stratification by employment status. In studies of occupational exposures, these differences may cause uncontrollable confounding if non-employed women are treated as unexposed instead of excluded from analysis. Am. J. Ind. Med. 60:329-341, 2017. © 2017 Wiley Periodicals, Inc.