Pregnant and moving: understanding residential mobility during pregnancy and in the first year of life using a prospective birth cohort

Neighborhood opportunity and residential instability: associations with mental health in middle childhood

BACKGROUND

Neighborhood quality may contribute to child mental health, but families with young children often move, and residential instability has also been tied to adverse mental health. This study's primary goal was to disentangle the effects of neighborhood quality from those of residential instability on mental health in middle childhood.

METHODS

1,946 children from 1,652 families in the Upstate KIDS cohort from New York state, US, were followed prospectively from birth to age 10. Residential addresses were linked at the census tract level to the Child Opportunity Index 2.0, a multidimensional indicator of neighborhood quality. The number of different addresses reported from birth to age 10 was counted to indicate residential instability, and the change in COI quintile indicated social mobility. Parents completed three assessments of attention-deficit/hyperactivity disorder, problematic behavior, and internalizing psychopathology symptoms at ages 7, 8, and 10. Child and family covariates were selected a priori to adjust sample characteristics, increase estimate precision, and account for potential confounding.

RESULTS

In unadjusted models, higher neighborhood quality at birth was associated with fewer psychopathology symptoms in middle childhood, but associations were largely mediated by residential instability. In adjusted models, residential instability was associated with more psychopathology symptoms, even accounting for social mobility. Neighborhood quality at birth had indirect effects on child mental health symptoms through residential instability.

CONCLUSIONS

Children born into lower-quality neighborhoods moved more, and moving more was associated with higher psychopathology symptoms. Findings were similar across different timings of residential moves, for girls and boys, and for children who did not experience a major life event. Additional research is needed to better understand which aspects of moving are most disruptive to young children.

Association between fine particulate matter (PM2.5) and infant mortality in a North Carolina birth cohort (2003-2015)

Background

While the association between fine particulate matter (PM2.5) and adult mortality is well established, few studies have examined the association between long-term PM2.5 exposure and infant mortality.

Methods

We conducted an unmatched case-control study of 5992 infant mortality cases and 60,000 randomly selected controls from a North Carolina birth cohort (2003-2015). PM2.5 during critical exposure periods (trimesters, pregnancy, first month alive) was estimated using residential address and a national spatiotemporal model at census block centroid. We fit adjusted logistic regression models and calculated odds ratios (ORs) and 95% confidence intervals (CIs). Due to differences in PM2 .5 over time, we stratified analyses into two periods: 2003-2009 (mean = 12.1 µg/m3, interquartile range [IQR]: 10.8-13.5) and 2011-2015 (mean = 8.4 µg/m3, IQR: 7.7-9.0). We assessed effect measure modification by birthing parent race/ethnicity, full-term birth, and PM2.5 concentrations.

Results

For births 2003-2015, the odds of infant mortality increased by 12% (95% CI: 1.06, 1.17) per 4.0 µg/m3 increase in PM2.5 exposure averaged over the pregnancy. After stratifying, we observed an increase of 4% (95% CI: 0.95, 1.14) for births in 2003-2009 and a decrease of 15% (95% CI: 0.72, 1.01) for births in 2011-2015. Among infants with higher PM2.5 exposure (≥12 µg/m3) during pregnancy, the odds of infant mortality increased (OR: 2.69; 95% CI: 2.17, 3.34) whereas the lower exposure (<8 µg/m3) group reported decreased odds (OR: 0.50; 95% CI: 0.28, 0.89).

Conclusions

We observed differing associations of PM2.5 exposure with infant mortality across higher versus lower PM2.5 concentrations. Research findings suggest the importance of accounting for long-term trends of decreasing PM2.5 concentrations in future research.

Long-term ambient sulfur dioxide exposure during gestation and preterm birth in North Carolina, 2003-2015

BACKGROUND

Coal-fired power plants are major contributors of ambient sulfur dioxide (SO2) air pollution. Epidemiological literature suggests an adverse association between SO2 exposure during gestation and preterm birth (PTB; <37 weeks completed gestation). PTB is strongly associated with infant mortality and increased risk for later life morbidities.

OBJECTIVE

We investigated associations between SO2 and PTB in North Carolina and evaluated whether the associations were modified by race/ethnicity.

METHODS

We assembled a retrospective, administrative cohort of singleton births in North Carolina from 2003-2015. We used US EPA EQUATES data to assign long-term SO2 gestational exposures to eligible births for the entire pregnancy and by trimester. We used multivariable generalized linear regression to estimate risk differences (RD (95%CI)) per 1-ppb increase in SO2, adjusted for gestational parent education, Medicaid status, marital status, and season of conception. Multi-pollutant models were additionally adjusted for other criteria air co-pollutants (O3, PM2.5, NO2).

RESULTS

The median SO2 (24-hour average) across exposure windows was ~1.5 (IQR: 1.8) ppb. The overall baseline risk for PTB was 8,756 per 100,000 live births. When stratified by race/ethnicity, the baseline risk for PTB was 12215, 7824, and 7187 per 100,000 live births among non-Hispanic Black, non-Hispanic white, and Hispanic births, respectively. RDs per 1-ppb increase in SO2 averaged across the entire pregnancy were 317.0 (95%CI: 279.4, 354.5) and 568.2 (95%CI: 500.3, 636.1) per 100,000 live births for single- and multi-pollutant models, respectively. For the PTB multi-pollutant models, we observed similar RDs for non-Hispanic Black participants (669.6 [95%CI: 573.9, 765.2]) and non-Hispanic white participants (635.4 [95%CI: 557.2, 713.6]) with smaller RDs for Hispanic participants (336.8 [95%CI: 241.3, 432.2]).

SIGNIFICANCE

The results for our adjusted single- and multi-pollutant models showed adverse associations between SO2 and PTB, with some evidence of effect measure modification by race/ethnicity within subcategories of PTB.

Associations between Individual- and Structural-Level Racism and Gestational Age at Birth in the Nulliparous Pregnancy Outcomes Study: Monitoring Mothers-to-Be

The purpose of this study was to investigate the associations between multilevel racism and gestational age at birth among nulliparous women. We conducted a secondary analysis of data of the nuMoM2b Study (2010-2013) to examine the associations between individual- and structural-level experiences of racism and discrimination and gestational age at birth among nulliparous women (n = 9148) at eight sites across the U.S. Measures included the individual Experiences of Discrimination (EOD) scale and the Index of Concentration at the Extremes (ICE) to measure structural racism. After adjustment, we observed a significant individual and structural racism interaction on gestational length (p = 0.012). In subgroup analyses, we found that among those with high EOD scores, women who were from households concentrated in the more privileged group had significantly longer gestations (β = 1.27, 95% CI: 0.48, 2.06). Women who reported higher EOD scores and more economic privilege had longer gestations, demonstrating the moderating effect of ICE as a measure of structural racism. In conclusion, ICE may represent a modifiable factor in the prevention of adverse birth outcomes in nulliparas.

Residential and healthcare mobility during pregnancy among women living with HIV in the UK, 2009-2019

INTRODUCTION

The extent to which individuals living with HIV experience residential and healthcare mobility during pregnancy in the UK is unknown. We aimed to determine a minimum estimate of residential and healthcare mobility during pregnancy in people living with HIV in the UK in 2009-2019 to explore patterns of and factors associated with mobility and to assess whether mobility was associated with specific HIV outcomes.

METHODS

We analyzed data from the Integrated Screening Outcomes Surveillance Service to assess pregnancies with HIV in the UK and included livebirths and stillbirths with estimated delivery in 2009-2019. Residential mobility was defined as changing residential postcode between notification and delivery, and healthcare mobility was defined as changing NHS Trust or Strategic Health Authority (SHA) in that same timeframe. We used logistic regression to determine factors associated with residential and healthcare mobility and with detectable delivery viral load.

RESULTS

Among 10 305 pregnancies, 19.6% experienced residential mobility, 8.1% changed NHS Trust, and 4.5% changed SHA during pregnancy. Mobility was more likely to be experienced by younger women, migrants, and those with new antenatal diagnosis; residential but not healthcare mobility declined over time. In a fully adjusted model, mobility was not associated with having a detectable viral load at delivery. Higher proportions of infants were lost to follow-up after mobile pregnancies than after non-mobile pregnancies.

CONCLUSIONS

This analysis provides new knowledge on mobility during pregnancy in the context of HIV, but further research is needed to understand its broader impacts and its utility as a marker to help identify families requiring additional follow-up and support.

Risk of Death at 1 Year Following Postpartum Opioid Exposure

OBJECTIVE

Opioids are commonly prescribed to women for acute pain following childbirth. Postpartum prescription opioid exposure is associated with adverse opioid-related morbidities but the association with all-cause mortality is not well studied. This study aimed to examine the association between postpartum opioid prescription fills and the 1-year risk of all-cause mortality among women with live births.

METHODS

In a retrospective cohort study of live births among women enrolled in Tennessee Medicaid (TennCare) between 2007 and 2015, we compared women who filled two or more postpartum outpatient opioid prescriptions (up to 41 days of postdelivery discharge) to women who filled one or fewer opioid prescription. Women were followed from day 42 postdelivery discharge through 365 days of follow-up or date of death. Deaths were identified using linked death certificates (2007-2016). We used Cox's proportional hazard regression and inverse probability of treatment weights to compare time to death between exposure groups while adjusting for relevant confounders. We also examined effect modification by delivery route, race, opioid use disorder, use of benzodiazepines, and mental health condition diagnosis.

RESULTS

Among 264,135 eligible births, 216,762 (82.1%) had one or fewer maternal postpartum opioid fills and 47,373 (17.9%) had two or more fills. There were 182 deaths during follow-up. The mortality rate was higher in women with two or more fills (120.5 per 100,000 person-years) than in those with one or fewer (57.7 per 100,000 person-years). The risk of maternal death remained higher in participants exposed to two or more opioid fills after accounting for relevant covariates using inverse probability of treatment weighting (adjusted hazard ratio: 1.46 [95% confidence interval: 1.01, 2.09]). Findings from stratified analyses were consistent with main findings.

CONCLUSION

Filling two or more opioid prescriptions during the postpartum period was associated with a significant increase in 1-year risk of death among new mothers.

KEY POINTS

· Opioid prescribing in the postpartum period is common.. · Prior studies show that >1 postnatal opioid fill is associated with adverse opioid-related events.. · > 1 opioid fill within 42 days of delivery was associated with an increase in 1-year risk of death..

Associations between individual and structural level racism and gestational age at birth in the Nulliparous Pregnancy Outcomes Study: Monitoring mothers-to-be

The purpose of this study was to investigate the associations between multilevel racism and gestational age at birth among nulliparous non-Hispanic Black, non-Hispanic White and Hispanic women. We conducted a secondary analysis of data of the nuMoM2b Study (2010-2013) to examine the associations between individual and structural-level experiences of racism and discrimination and gestational age at birth among nulliparous women (n=7,732) at eight sites across the U.S. Measures included the individual Experiences of Discrimination (EOD) scale and the Index of Concentration (ICE) at the Extremes to measure structural racism. After adjustment,we observed a significant individual and structural racism interaction on gestational length (p=0.03). In subgroup analyses, we found that among these with high EOD scores, women who were from households concentrated in the more privileged group had significantly longer gestations (β = 1.07, 95% CI: 0.24, 1.90). Women who reported higher EOD scores and more economic privilege had longer gestations, demonstrating the moderating effect of ICE as a measure of structural racism. In conclusion, ICE may represent a modifiable factor in the prevention of adverse birth outcomes in nulliparas.

Sulfur dioxide reduction at coal-fired power plants in North Carolina and associations with preterm birth among surrounding residents

Coal-fired power plants (CFPP) are major contributors of air pollution, including the majority of anthropogenic sulfur dioxide (SO2) emissions, which have been associated with preterm birth (PTB). To address a 2002 North Carolina (NC) policy, 14 of the largest NC CFPPs either installed desulfurization equipment (scrubbers) or retired coal units, resulting in substantial reductions of SO2 air emissions. We investigated whether SO2 air emission reduction strategies at CFPPs in NC were associated with changes in prevalence of PTB in nearby communities.

Methods

We used US EPA Air Markets Program Data to track SO2 emissions and determine the implementation dates of intervention at CFPPs and geocoded 2003-2015 NC singleton live births. We conducted a difference-in-difference analysis to estimate change in PTB associated with change in SO2 reduction strategies for populations living 0-<4 and 4-<10 miles from CFPPs pre- and postintervention, with a comparison of those living 10-<15 miles from CFPPs.

Results

With the spatial-temporal exposure restrictions applied, 42,231 and 41,218 births were within 15 miles of CFPP-scrubbers and CFPP-retired groups, respectively. For residents within 4-<10 miles from a CFPP, we estimated that the absolute prevalence of PTB decreased by -1.5% [95% confidence interval (CI): -2.6, -0.4] associated with scrubber installation and -0.5% (95% CI: -1.6, 0.6) associated with the retirement of coal units at CFPPs. Our findings were imprecise and generally null-to-positive among those living within 0-<4 miles regardless of the intervention type.

Conclusions

Results suggest a reduction of PTB among residents 4-<10 miles of the CFPPs that installed scrubbers.

Characteristics of movers and predictors of residential mobility in the Atherosclerosis Risk in Communities (ARIC) cohort

Current efforts to characterize movers and identify predictors of moving have been limited. We used the ARIC cohort to characterize non-movers, short-distance movers, and long-distance movers, and employed best subset algorithms to identify important predictors of moving, including interactions between characteristics. Short- and long-distance movers were notably different from non-movers, and important predictors of moving differed based on the distance of the residential move. Importantly, systematic inclusion of interaction terms enhanced model fit and was substantively meaningful. This work has important implications for epidemiologic studies of contextual exposures and those treating residential mobility as an exposure.

Does Where You Live Predict What You Say? Associations between Neighborhood Factors, Child Sleep, and Language Development

Language ability is strongly related to important child developmental outcomes. Family-level socioeconomic status influences child language ability; it is unclear if, and through which mechanisms, neighborhood-level factors impact child language. The current study investigated the association between neighborhood factors (deprivation and disorder) assessed before birth and child language outcomes at age 5, with sleep duration as a potential underlying pathway. Secondary analysis was conducted on data collected between 2008 and 2018 on a subsample of 2444 participants from the All Our Families cohort study (Calgary, Canada) for whom neighborhood information from pregnancy could be geocoded. Neighborhood deprivation was determined using the Vancouver Area Neighborhood Deprivation Index (VANDIX), and disorder was assessed using crime reports. Mothers reported on their children’s sleep duration and language ability. Multilevel modeling indicated that greater neighborhood deprivation and disorder during pregnancy were predictive of lower scores on the Child Communication Checklist–2 (CCC–2) at 5 years. Path analyses revealed an indirect effect of neighborhood disorder on language through child sleep duration at 12 months. These results add to growing evidence that child development should be considered within the context of multiple systems. Sleep duration as an underlying link between environmental factors and child language ability warrants further study as a potential target for intervention.

Understanding the Pathways from Prenatal and Post-Birth PM2.5 Exposure to Infant Death: An Observational Analysis Using US Vital Records (2011-2013)

We studied the relationship of prenatal and post-birth exposure to particulate matter < 2.5 μm in diameter (PM_2.5) with infant mortality for all births between 2011 and 2013 in the conterminous United States. Prenatal exposure was defined separately for each trimester, post-birth exposure was defined in the 12 months following the prenatal period, and infant mortality was defined as death in the first year of life. For the analysis, we merged over 10 million cohort-linked live birth-infant death records with daily, county-level PM_2.5 concentration data and then fit a Structural Equation Model controlling for several individual- and county-level confounders. We estimated direct paths from the two exposures to infant death as well as indirect paths from the prenatal exposure to the outcome through preterm birth and low birth weight. Prenatal PM_2.5 exposure was positively associated with infant death across all trimesters, although the relationship was strongest in the third trimester. The direct pathway from the prenatal exposure to the outcome accounted for most of this association. Estimates for the post-birth PM_2.5-infant death relationship were less precise. The results from our study add to a growing literature that provides evidence in favor of the potential harmful effects on human health of low levels of air pollution.

Human-Animal Interaction and Perinatal Mental Health: A Narrative Review of Selected Literature and Call for Research

There is a paucity of research exploring how relationships with household pets may impact maternal mental health. We are unaware of any study to date that has examined associations between individuals' relationships with their pets and psychological adjustment in the perinatal period. Using a biobehavioral lens, this paper provides a narrative overview of the literature on perinatal mental health and human-animal interaction (HAI). We focus on the role of social relationships, stress, and stress reduction in relation to perinatal mental health; the role of HAI in perceptions of social support, stressors, and stress reduction; and gaps in empirical knowledge concerning the role of HAI in perinatal mental health. Finally, we integrate contemporary biobehavioral models of perinatal mental health and HAI (i.e., Comprehensive Model of Mental Health during the Perinatal Period and the HAI-HPA Transactional Model) to propose a new conceptual framework that depicts ways in which HAI during the perinatal period may influence maternal and child health and wellbeing. To our knowledge, this is the first paper to consider the role of HAI in biobehavioral responses and mental health during the perinatal period. We conclude with recommendations for future research and improved perinatal care.

Longitudinal measures of neighborhood poverty and income inequality are associated with adverse birth outcomes in Texas

BACKGROUND

Inequity in adverse birth outcomes between black and white women in the U.S. is persistent, despite decades of research and prevention efforts. Neighborhood environments are plausibly related to pre-pregnancy health and other risk factors for adverse birth outcomes and may help explain black/white inequities. Despite the fact that neighborhoods change over time, most prior work has relied upon cross-sectional measures of neighborhood economic contexts.

METHODS

We used birth certificates for non-Hispanic black and white women in Texas (2009-2011, N = 470,896) to examine whether longitudinal measures of neighborhood economic context (poverty and income inequality, based on census tract data from 1990 to 2010) were associated with preterm birth, low birthweight and small-for-gestational-age (SGA) with hierarchical generalized linear models. We also tested whether (1) the longitudinal measures explained black/white inequities or (2) moderated the effect of race on the birth outcomes. Finally, we compared the models with longitudinal measures to models with cross-sectional measures of neighborhood economic context.

RESULTS

Longitudinal measures of neighborhood economic context were associated with all three birth outcomes, but did not explain racial inequities. Except for income inequality and SGA, there was no evidence of moderation by race. Substituting cross-sectional measures of economic context for longitudinal ones resulted in similar findings.

CONCLUSION

Policies that either address structural neighborhood-level economic disadvantage or mitigate the effects of such disadvantage are warranted to improve the health of mothers and prevent adverse birth outcomes.

Prenatal care among mothers involved with child protection services in Manitoba: a retrospective cohort study

BACKGROUND

Prenatal care is one of the most widely used preventive health services; however, use varies substantially. Our objective was to examine prenatal care among women with a history of having a child placed in out-of-home care, and whether their care differed from care among women who did not.

METHODS

We used linkable administrative data to create a population-based cohort of women whose first 2 children were born in Manitoba, Canada, between Apr. 1, 1998, and Mar. 1, 2015. We measured the level of prenatal care using the Revised Graduated Prenatal Care Utilization Index, which categorizes care into 5 groups: intensive, adequate, intermediate, inadequate and no care. We compared level of prenatal care for women whose first child was placed in care with level of prenatal care for women who had no contact with care services, using 2 multinomial logistic regression models to calculate odds ratios (ORs).

RESULTS

In a cohort of 52 438 mothers, 1284 (2.4%) had their first child placed in out-of-home care before conception of their second child. Mothers whose first child was placed in care had much higher rates of inadequate prenatal care during the pregnancy with their second child than mothers whose first child was not placed in care (33.0% v. 13.4%). The odds of having inadequate rather than adequate prenatal care were more than 4 times higher (OR 4.29, 95% CI 3.68 to 5.01) for women who had their first child placed in care than for women who did not have their first child placed in care.

INTERPRETATION

Mothers with a history of having a child taken into care by the child protection services system are at higher risk of having inadequate or no prenatal care in a subsequent pregnancy compared with mothers with no history of involvement with child protection services.

The Impact of Neighbourhood Deprivation on Embryonic Growth Trajectories: Rotterdam Periconception Cohort

Background: Neighbourhood deprivation is a risk factor for impaired health and adverse pregnancy outcomes. We investigated whether living in a deprived neighbourhood is associated with embryonic growth. Methods: From the Predict cohort, we studied 566 women who underwent repeated first trimester ultrasound examinations. Crown rump length (CRL; n = 1707) and embryonic volume (EV; n = 1462) were measured using three-dimensional techniques. Neighbourhood deprivation was assessed using the neighbourhood status scores (NSS) of the Dutch Social Cultural Planning office. A high NSS represents a non-deprived neighbourhood. Associations between the NSS and embryonic growth were investigated using linear mixed models. Adjustment was performed for individual-level factors: maternal age, geographic origin, educational level, BMI, folic acid supplement use, fruit and vegetable intake, alcohol use and smoking habits. Results: The NSS was negatively associated with embryonic growth: a higher score (a less deprived neighbourhood) was associated with a smaller CRL and EV; adjusted β: −0.025 (95% CI −0.046, −0.003) and adjusted β: −0.015 (95% CI −0.026, −0.003). At 11 weeks of pregnancy, we observed a 0.55 cm³ smaller EV (7.65 cm³ vs. 7.10 cm³) and 1.08 mm smaller CRL (43.14 mm vs. 42.06 mm) in the highest compared to the lowest category. Conclusion: In deprived neighbourhoods, embryos are larger than in non-deprived neighbourhoods.

Air pollution, neighborhood deprivation, and autism spectrum disorder in the Study to Explore Early Development

Background

To examine whether neighborhood deprivation modifies the association between early life air pollution exposure and autism spectrum disorder (ASD), we used resources from a multisite case-control study, the Study to Explore Early Development.

Methods

Cases were 674 children with confirmed ASD born in 2003-2006; controls were 855 randomly sampled children born during the same time period and residents of the same geographic areas as cases. Air pollution was assessed by roadway proximity and particulate matter <2.5 μm (PM_2.5) exposure during pregnancy and first year of life. To characterize neighborhood deprivation, an index was created based on eight census tract-level socioeconomic status-related parameters. The continuous index was categorized into tertiles, representing low, moderate, and high deprivation. Logistic regression was used to estimate odds ratios (ORs) and corresponding 95% confidence intervals (CIs).

Results

Neighborhood deprivation modified (P _{for interaction} = 0.08) the association between PM_2.5 exposure during the first year of life and ASD, with a stronger association for those living in high (OR = 2.42, 95% CI = 1.20, 4.86) rather than moderate (OR=1.21, 95% CI = 0.67, 2.17) or low (OR=1.46, 95% CI = 0.80, 2.65) deprivation neighborhoods. Departure from additivity or multiplicativity was not observed for roadway proximity or exposures during pregnancy.

Conclusion

These results provide suggestive evidence of interaction between neighborhood deprivation and PM_2.5 exposure during the first year of life in association with ASD.

Racial and ethnic disparities in adverse birth outcomes: Differences by racial residential segregation

Racial and ethnic disparities in adverse birth outcomes have persistently been wide and may be explained by individual and area-level factors. Our primary objective was to determine if county-level black-white segregation modified the association between maternal race/ethnicity and adverse birth outcomes using birth records from the National Center for Health Statistics (2012). Based on maternal residence at birth, county-level black-white racial residential segregation was calculated along five dimensions of segregation: evenness, exposure, concentration, centralization, and clustering. We conducted a two-stage analysis: (1) county-specific logistic regression to determine whether maternal race and ethnicity were associated with preterm birth and term low birth weight; and (2) Bayesian meta-analyses to determine if segregation moderated these associations. We found greater black-white and Hispanic-white disparities in preterm birth in racially isolated counties (exposure) relative to non-isolated counties. We found reduced Hispanic-white disparities in term low birth weight in racially concentrated and centralized counties relative to non-segregated counties. Area-level poverty explained most of the moderating effect of segregation on disparities in adverse birth outcomes, suggesting that area-level poverty is a mediator of these associations. Segregation appears to modify racial/ethnic disparities in adverse birth outcomes. Therefore, policy interventions that reduce black-white racial isolation, or buffer the poor social and economic correlates of segregation, may help to reduce disparities in preterm birth and term low birth weight.

Residence change during the first trimester of pregnancy and adverse birth outcomes

BACKGROUND

There are few published studies evaluating the impact of perinatal residence change on infant outcomes and whether these associations differ by socioeconomic status.

METHODS

We conducted a population-based cohort study using Washington State birth certificate data from 2007 to 2014 to assess whether women who moved during the first trimester of pregnancy (n=28 011) had a higher risk of low birth weight, preterm birth and small for gestational age than women who did not move during the first trimester (n=112 367). 'Non-first-trimester movers' were frequency matched 4:1 to movers by year. We used generalised linear models to calculate risk ratios and risk differences adjusted for maternal age, race, marital status, parity, education, smoking, income and insurance payer for the birth. We also stratified analyses by variables related to socioeconomic status to see whether associations differed across socioeconomic strata.

RESULTS

Moving in the first trimester was associated with an increased risk of low birth weight (6.4% vs 4.5%, adjusted risk ratio 1.37 (95% CI 1.29 to 1.45)) and preterm birth (9.1% vs 6.4%, adjusted risk ratio 1.42 (95% CI 1.36 to 1.49)) and a slight increased risk of small for gestational age (9.8% vs 8.7%, adjusted risk ratio 1.09 (95% CI 1.00 to 1.09)). Residence change was associated with low birth weight and preterm birth in all socioeconomic strata.

CONCLUSION

Moving during the first trimester of pregnancy may be a risk factor for adverse birth outcomes in US women. Healthcare providers may want to consider screening for plans to move and offering support.

Predictors of residential mobility and its impact on air pollution exposure among children diagnosed with early childhood leukemia

Epidemiology studies relying on one address to assign exposures over time share common methodological limitations in failing to account for mobility that may introduce potential exposure misclassification. Using Texas birth certificate and cancer registry data, we identified predictors of residential mobility among mothers of children diagnosed with early childhood leukemia in Texas from 1995 to 2011. We used U.S. Environmental Protection Agency (EPA) National Air Toxics Assessment data to estimate residential levels of benzene and 1,3-butadiene based on addresses at birth and diagnosis and applied mixed-effects ordinal logistic regression models to evaluate differences in exposure classification between the two time periods. In total, 55% of children moved from time of birth to diagnosis, although they generally did not move far (median distance moved was 8 km). Predictors of mobility, at delivery, included younger age, being unmarried and living in neighborhoods with high benzene levels, and, at diagnosis, increasing child's age and living in neighborhoods with low poverty rates. We observed that the odds of being assigned to a higher exposure quartile at diagnosis relative to the time of birth decreased by 31% for 1,3-butadiene (OR = 0.69, 95% CI 0.59-0.82) and by 12% for benzene (OR = 0.88, 95% CI 0.75, 1.05).

Using Index of Concentration at the Extremes as Indicators of Structural Racism to Evaluate the Association with Preterm Birth and Infant Mortality-California, 2011-2012

Disparities in adverse birth outcomes for Black women continue. Research suggests that societal factors such as structural racism explain more variation in adverse birth outcomes than individual-level factors and societal poverty alone. The Index of Concentration at the Extremes (ICE) measures spatial social polarization by quantifying extremes of deprived and privileged social groups using a single metric and has been shown to partially explain racial disparities in black carbon exposures, mortality, fatal and non-fatal assaults, and adverse birth outcomes such as preterm birth and infant mortality. The objective of this analysis was to assess if local measures of racial and economic segregation as proxies for structural racism are associated and preterm birth and infant mortality experienced by Black women residing in California. California birth cohort files were merged with the American Community Survey by zip code (2011-2012). The ICE was used to quantify privileged and deprived groups (i.e., Black vs. White; high income vs. low income; Black low income vs. White high income) by zip code. ICE scores range from - 1 (deprived) to 1 (privileged). ICE scores were categorized into five quintiles based on sample distributions of these measures: quintile 1 (least privileged)-quintile 5 (most privileged). Generalized linear mixed models were used to test the likelihood that ICE measures were associated with preterm birth or with infant mortality experienced by Black women residing in California. Black women were most likely to reside in zip codes with greater extreme income concentrations, and moderate extreme race and race + income concentrations. Bivariate analysis revealed that greater extreme income, race, and race + income concentrations increased the odds of preterm birth and infant mortality. For example, women residing in least privileged zip codes (quintile 1) were significantly more likely to experience preterm birth (race + income ICE OR = 1.31, 95% CI = 1.72-1.46) and infant mortality (race + income ICE OR = 1.70, 95% CI = 1.17-2.47) compared to women living in the most privileged zip codes (quintile 5). Adjusting for maternal characteristics, income, race, and race + income concentrations remained negatively associated with preterm birth. However, only race and race + income concentrations remained associated with infant mortality. Findings support that ICE is a promising measure of structural racism that can be used to address racial disparities in preterm birth and infant mortality experienced by Black women in California.

Retention strategies in longitudinal cohort studies: a systematic review and meta-analysis

BACKGROUND

Participant retention strategies that minimise attrition in longitudinal cohort studies have evolved considerably in recent years. This study aimed to assess, via systematic review and meta-analysis, the effectiveness of both traditional strategies and contemporary innovations for retention adopted by longitudinal cohort studies in the past decade.

METHODS

Health research databases were searched for retention strategies used within longitudinal cohort studies published in the 10-years prior, with 143 eligible longitudinal cohort studies identified (141 articles; sample size range: 30 to 61,895). Details on retention strategies and rates, research designs, and participant demographics were extracted. Meta-analyses of retained proportions were performed to examine the association between cohort retention rate and individual and thematically grouped retention strategies.

RESULTS

Results identified 95 retention strategies, broadly classed as either: barrier-reduction, community-building, follow-up/reminder, or tracing strategies. Forty-four of these strategies had not been identified in previous reviews. Meta-regressions indicated that studies using barrier-reduction strategies retained 10% more of their sample (95%CI [0.13 to 1.08]; p = .01); however, studies using follow-up/reminder strategies lost an additional 10% of their sample (95%CI [- 1.19 to - 0.21]; p = .02). The overall number of strategies employed was not associated with retention.

CONCLUSIONS

Employing a larger number of retention strategies may not be associated with improved retention in longitudinal cohort studies, contrary to earlier narrative reviews. Results suggest that strategies that aim to reduce participant burden (e.g., flexibility in data collection methods) might be most effective in maximising cohort retention.

Mobility patterns and associated factors among pregnant internal migrant women in China: a cross-sectional study from a National Monitoring Survey

Background

Residential instability during pregnancy has been linked to poor health outcomes. As a first step toward providing better health care to pregnant migrant women, the size and characteristics of this population and factors associated with mobility during pregnancy should be studied.

Methods

Using the “Monitoring Data of Chinese Migrants” for 2012, from the Chinese National Population and Family Planning Commission, this study explored mobility patterns during pregnancy and associated factors among migrants within China. From a library of 158,556 participants, two subsamples were selected. Percentages, with chi-squared tests, and means and standard deviations, with ANOVAs, were adopted to describe mobility patterns during pregnancy (always staying in sending area, mainly staying in sending area, mainly staying in receiving area, and always staying in receiving area) and delivery location choice. Logistic regression analysis was used to explore the associated factors.

Results

We found that the percentage of migrants always or mainly staying in receiving areas during pregnancy rose from nearly 40% in 1985 to more than 80% in 2012, while the percentage of migrants who were mobile between receiving and sending areas during pregnancy fluctuated between 30 and 40% before 1995, and between 40 and 45% after 1995, decreasing to around 40% after 2008. The percentage of respondents who chose to deliver in receiving areas fluctuated but increased from 10% in 1985 to more than 50% in 2011. Among respondents who had delivered during the last year of the survey period, families with older pregnant women (OR = 1.09, 95% CI 1.05–1.13), their own housing (OR = 5.66, 95% CI 2.45–13.05), longer time in the receiving area (OR = 1.14, 95% CI 1.09–1.20), and strong will to integrate (OR = 1.32, 95% CI 1.15–1.51) always stayed in the receiving area during pregnancy, rather than the sending area, and families with broadly similar characteristics were inclined to choose the receiving area for their delivery.

Conclusions

The mobility patterns of pregnant migrant women in China have been changing in recent years, with the percentage of them staying in receiving areas during pregnancy and delivering there increasing. Individual and family characteristics were also associated with mobility patterns and delivery location choice.

Electronic supplementary material

The online version of this article (10.1186/s12884-018-1813-2) contains supplementary material, which is available to authorized users.

Factors associated with residential mobility during pregnancy

Our objective was to determine the factors associated with residential moving during pregnancy, as it may increase stress during pregnancy and affect birth outcomes. Data were obtained from the Conditions Affecting Neurocognitive Development and Learning in Early Childhood (CANDLE) study. Participants were recruited from December 2006 to June 2011 and included 1,448 pregnant women. The average gestational age at enrollment was 23 weeks. The primary outcome of residential mobility was defined as any change in address during pregnancy. Multivariate regression was used to assess the adjusted associations of factors with residential mobility. Out of 1,448 participants, approximately 9 percent moved between baseline (enrollment) and delivery. After adjusting for covariates, mothers with lower educational attainment [less than high school (adjusted odds ratio [aOR] = 3.74, 95% confidence interval [CI] = 1.78, 7.85) and high school/technical school (aOR = 3.57, 95% CI = 2.01, 6.32) compared to college degree or higher], and shorter length of residence in neighborhood were more likely to have moved compared to other mothers. Length of residence was protective of mobility (aOR = 0.91, 95% CI = 0.86, 0.96 per year). Increased understanding of residential mobility during pregnancy may help improve the health of mothers and their children.

Measurement error in mobile source air pollution exposure estimates due to residential mobility during pregnancy

Prenatal air pollution exposure is frequently estimated using maternal residential location at the time of delivery as a proxy for residence during pregnancy. We describe residential mobility during pregnancy among 19,951 children from the Kaiser Air Pollution and Pediatric Asthma Study, quantify measurement error in spatially resolved estimates of prenatal exposure to mobile source fine particulate matter (PM_2.5) due to ignoring this mobility, and simulate the impact of this error on estimates of epidemiologic associations. Two exposure estimates were compared, one calculated using complete residential histories during pregnancy (weighted average based on time spent at each address) and the second calculated using only residence at birth. Estimates were computed using annual averages of primary PM_2.5 from traffic emissions modeled using a Research LINE-source dispersion model for near-surface releases (RLINE) at 250 m resolution. In this cohort, 18.6% of children were born to mothers who moved at least once during pregnancy. Mobile source PM_2.5 exposure estimates calculated using complete residential histories during pregnancy and only residence at birth were highly correlated (r_S>0.9). Simulations indicated that ignoring residential mobility resulted in modest bias of epidemiologic associations toward the null, but varied by maternal characteristics and prenatal exposure windows of interest (ranging from -2% to -10% bias).

Characterizing Social Determinants of Health for Adolescent Mothers during the Prenatal and Postpartum Periods

PURPOSE

Significant racial disparities and continuing poor birth outcomes make adolescent pregnancy a significant public health concern in the United States despite declining pregnancy rates. Social determinants of health are associated with increased likelihood of pregnancy and poor maternal and child health outcomes. This study aims to characterize specific elements of social determinants of health in a cohort of predominantly Latina adolescent mothers.

METHODS

Between February 2007 and August 2008, 106 pregnant adolescents participated in a study with assessments at 20 to 24 weeks of gestation, and at 3 and 6 months postpartum. Survey questions addressed residential mobility, financial support and childcare, and perceived need for and use of community resources. Comparative analysis assessed differences between adolescents by age (<16 vs. ≥16 years old) and ethnicity (Latina vs. non-Latina).

FINDINGS

Adolescent mothers experienced high rates of residential mobility, with 59.4% moving at least once in the year before their prenatal survey. Participants relied primarily on public aid (94-96%) and their parents (81-85%) for financial support. Latina participants were more likely than non-Latinas to rely on public aid. Although many participants reported needing financial support and housing, few used available services. Younger adolescents relied less often on the father of the baby for support than older adolescents.

CONCLUSIONS

Adolescent mothers' high rates of residential mobility and increasing reliance on public assistance highlight resource gaps that potentially put them and their children at risk for poor outcomes. Targeted efforts to augment systemic support in these domains are a critical component of addressing health disparities for this population.

Family Structure, Residential Mobility, and Environmental Inequality

This study combines micro-level data on families with children from the Panel Study of Income Dynamics with neighborhood-level industrial hazard data from the Environmental Protection Agency and neighborhood-level U.S. census data to examine both the association between family structure and residential proximity to neighborhood pollution and the micro-level, residential mobility processes that contribute to differential pollution proximity across family types. Results indicate the existence of significant family structure differences in household proximity to industrial pollution in U.S. metropolitan areas between 1990 and 1999, with single-mother and single-father families experiencing neighborhood pollution levels that are on average 46% and 26% greater, respectively, than those experienced by two-parent families. Moreover, the pollution gap between single-mother and two-parent families persists with controls for household and neighborhood socioeconomic, sociodemographic, and race/ethnic characteristics. Examination of underlying migration patterns reveals that single-mother, single-father, and two-parent families are equally likely to move in response to pollution. However, mobile single-parent families move into neighborhoods with significantly higher pollution levels than do mobile two-parent families. Thus, family structure differences in pollution proximity are maintained more by these destination neighborhood differences than by family structure variations in the likelihood of moving out of polluted neighborhoods.

Neighborhood racial composition and poverty in association with pre-pregnancy weight and gestational weight gain

BACKGROUND

Studies of neighborhood racial composition or neighborhood poverty in association with pregnancy-related weight are limited. Prior studies of neighborhood racial density and poverty has been in association with adverse birth outcomes and suggest that neighborhoods with high rates of poverty and racial composition of black residents are typically segregated and systematically isolated from opportunities and resources. These neighborhood factors may help explain the racial disparities in pre-pregnancy weight and inadequate weight gain. This study examined whether neighborhood racial composition and neighborhood poverty was associated with weight before pregnancy and weight gain during pregnancy and if this association differed by race.

METHODS

We used vital birth records of singleton births of 73,061 non-Hispanic black and white women in Allegheny County, PA (2003-2010). Maternal race and ethnicity, pre-pregnancy body-mass-index (BMI), gestational weight gain and other individual-level characteristics were derived from vital birth record data, and measures of neighborhood racial composition (percentage of black residents in the neighborhood) and poverty (percentage of households in the neighborhood below the federal poverty) were derived using US Census data. Multilevel log binomial regression models were performed to estimate neighborhood racial composition and poverty in association with pre-pregnancy weight (i.e., overweight/obese) and gestational weight gain (i.e., inadequate and excessive).

RESULTS

Black women as compared to white women were more likely to be overweight/obese before pregnancy and to have inadequate gestational weight gain (53.6% vs. 38.8%; 22.5% vs. 14.75 respectively). Black women living in predominately black neighborhoods were slightly more likely to be obese prior to pregnancy compared to black women living in predominately white neighborhoods (PR 1.10; 95% CI: 1.03, 1.16). Black and white women living in high poverty areas compared with women living in lower poverty areas were more likely to be obese prior to pregnancy; while only white women living in high poverty areas compared to low poverty areas were more likely gain an inadequate amount of weight during pregnancy.

CONCLUSIONS

Neighborhood racial composition and poverty may be important in understanding racial differences in weight among childbearing women.

Post-partum Residential Mobility Among a Statewide Representative Sample of California Women, 2003-2007

OBJECTIVES

Researchers often examine neighborhood socioeconomic environment and health during the perinatal period using geocoded addresses recorded on birth certificates at the time of delivery. Our objective was to assess the potential for post-partum neighborhood misclassification by examining whether women move neighborhoods during the immediate post-partum period, whether they move to neighborhoods of different socioeconomic status (SES), and whether mobility differs by maternal characteristics.

METHODS

We used data from the 2003-2007 California Maternal and Infant Health Assessment (MIHA), an annual, statewide-representative survey of post-partum women, to examine women's neighborhood mobility patterns between giving birth and completing a survey 2-7 months post-partum. We examined whether women changed neighborhoods, whether moves were to neighborhoods of higher, lower, or similar socioeconomic status (SES), and whether these patterns differed by maternal race/ethnicity, maternal SES, or other demographic characteristics.

RESULTS

Overall, 93% of women either did not move neighborhoods or moved to a neighborhood of similar SES post-partum. Only 4% of women moved to a neighborhood of lower SES and 3% to an area of higher SES. Mothers who were non-Hispanic black or US-born Hispanic, young, unmarried, primiparous, or lower SES were slightly more likely to move overall and more likely to move to neighborhoods with different SES, compared to other women.

CONCLUSIONS

These findings suggest that geocoded addresses from birth certificates can be used to estimate women's neighborhood SES during the early post-partum period with little misclassification, an especially relevant finding for researchers using post-partum surveys.

Maternal residential proximity to major roadways, birth weight, and placental DNA methylation

BACKGROUND

Exposure to traffic pollution during fetal development has been associated with reduced fetal growth, and there is evidence to suggest that epigenetic mechanisms in the placenta in the form of variant DNA methylation may be a potential mechanism underlying this effect.

OBJECTIVES

To examine the association between residential proximity to nearest major roadway, as a marker of traffic-related pollution, fetal growth and placental DNA methylation.

METHODS

We obtained residential addresses, placenta samples, and demographic data from 471 women following delivery of term infants. Using generalized linear models we evaluated the association between living close to a major roadway (defined as living ≤150m from a primary highway or primary road or ≤50m from a secondary road) and fetal growth and DNA methylation of repetitive elements (LINE-1 and AluYb8). We evaluated epigenome-wide methylation in a subset of 215 women to further investigate specific variation in DNA methylation associated with proximity to major roadways.

RESULTS

Living close to a major roadway was associated with a 175.9g (95% CI: -319.4, -32.5; p=0.016) lower birth weight, 1.8 (95% CI: 0.9, 3.8; p=0.09) times the odds of being small for gestational age, and 0.82 percentage points (95% CI: -1.57, -0.07; p=0.03) lower mean placental LINE-1 methylation levels in fully adjusted models. In epigenome-wide analyses, 7 CpG sites were significantly associated with residential proximity to major roadways. Additional adjustment for placental methylation did not attenuate the association between roadway proximity and birth weight.

CONCLUSIONS

Living close to major roadways was associated with both lower fetal growth and significant placental epigenetic changes. However, the observed epigenetic changes appear insufficient to explain the observed association between roadway proximity and fetal growth.

Particulate air pollution, fetal growth and gestational length: The influence of residential mobility in pregnancy

BACKGROUND

It remains unclear as to whether neglecting residential mobility during pregnancy introduces bias in studies investigating air pollution and adverse perinatal outcomes, as most studies assess exposure based on residence at birth. The aim of this study was to ascertain whether such bias can be observed in a study on the effects of PM10 on risk of preterm birth and fetal growth restriction.

METHODS

This was a retrospective study using four pregnancy cohorts of women recruited in Connecticut, USA (N=10,025). We ascertained associations with PM10 exposure calculated using first recorded maternal address, last recorded address, and full address histories. We used a discrete time-to-event model for preterm birth, and logistic regression to investigate associations with small for gestational age (SGA) and term low birth weight (LBW).

RESULTS

Pregnant women tended to move to areas with lower levels of PM10. For all outcomes, there was negligible difference between effect sizes corresponding to exposures calculated with first, last and full address histories. For LBW, associations were observed for exposure in second trimester (OR 1.09; 95% CI: 1.04-1.14 per 1μg/m(3) PM10) and whole pregnancy (OR 1.08; 95% CI: 1.02-1.14). For SGA, associations were observed for elevated exposure in second trimester (OR 1.02; 95% CI: 1.00-1.04) and whole pregnancy (OR 1.03; 95% CI: 1.01-1.05). There was insufficient evidence for association with preterm birth.

CONCLUSION

PM10 was associated with both SGA and term LBW. However, there was negligible benefit in accounting for residential mobility in pregnancy in this study.

A population-based case-control study of stillbirth: the relationship of significant life events to the racial disparity for African Americans

Stillbirths (fetal deaths occurring at ≥20 weeks' gestation) are approximately equal in number to infant deaths in the United States and are twice as likely among non-Hispanic black births as among non-Hispanic white births. The causes of racial disparity in stillbirth remain poorly understood. A population-based case-control study conducted by the Stillbirth Collaborative Research Network in 5 US catchment areas from March 2006 to September 2008 identified characteristics associated with racial/ethnic disparity and interpersonal and environmental stressors, including a list of 13 significant life events (SLEs). The adjusted odds ratio for stillbirth among women reporting all 4 SLE factors (financial, emotional, traumatic, and partner-related) was 2.22 (95% confidence interval: 1.43, 3.46). This association was robust after additional control for the correlated variables of family income, marital status, and health insurance type. There was no interaction between race/ethnicity and other variables. Effective ameliorative interventions could have a substantial public health impact, since there is at least a 50% increased risk of stillbirth for the approximately 21% of all women and 32% of non-Hispanic black women who experience 3 or more SLE factors during the year prior to delivery.