Lisa Vinikoor-Imler

Neighborhood Conditions are Associated with Maternal Health Behaviors and Pregnancy Outcomes

Women residing in neighborhoods of low socioeconomic status are more likely to experience adverse reproductive outcomes; however, few studies explore which specific neighborhood features are associated with poor maternal health behaviors and pregnancy outcomes. Based upon our conceptual model, directly observed street-level data from four North Carolina US counties were used to create five neighborhood indices: physical incivilities (neighborhood degradation), social spaces (public space for socializing), walkability (walkable neighborhoods), borders (property boundaries), and arterial features (traffic safety). Singleton birth records (2001-2005) were obtained from the North Carolina State Center for Vital Statistics and maternal health behavior information (smoking, inadequate or excessive weight gain) and pregnancy outcomes (pregnancy-induced hypertension/pre-eclampsia, low birthweight, preterm birth) were abstracted. Race-stratified random effect models were used to estimate associations between neighborhood indices and womens reproductive behaviors and outcomes. In adjusted models, higher amounts of physical incivilities were positively associated with maternal smoking and inadequate weight gain, while walkability was associated with lower odds of these maternal health behaviors. Social spaces were also associated with inadequate weight gain during pregnancy. Among pregnancy outcomes, high levels of physical incivilities were consistently associated with all adverse pregnancy outcomes, and high levels of walkability were inversely associated with pregnancy-induced hypertension and preterm birth for Non-Hispanic white women only. None of the indices were associated with adverse birth outcomes for Non-Hispanic black women. In conclusion, certain neighborhood conditions were associated with maternal health behaviors and pregnancy outcomes.

The effects of exposure to particulate matter and neighbourhood deprivation on gestational hypertension

Gestational hypertension, pre-eclampsia and eclampsia are conditions that affect the health of both mothers and infants during and after pregnancy. Recent research indicates the importance of considering environmental, social and individual contributors to poor pregnancy outcomes. Our research examined particulate matter (PM) concentrations as one measure of environmental exposure and neighbourhood quality as one measure of the social environment. We used these measures, as well as maternal characteristics, to predict the risk of gestational hypertension (including pre-eclampsia and eclampsia). North Carolina Detailed Birth Record data for 2000-2003 were obtained and geocoded for all singleton births. Levels of PM(10) and PM(2.5) were determined using air quality data from the US Environmental Protection Agency. Information on a womans residential neighbourhood was determined from 2000 Census data. Modified Poisson regression models clustered by tract were used to examine the associations between PM levels, neighbourhood deprivation and maternal characteristics with gestational hypertension. Analysis was restricted to women residing within 20 km of a PM monitor. Both PM(10) and PM(2.5) were associated with gestational hypertension; the risk ratios for an interquartile range (IQR) increase in exposure were 1.07 [95% confidence interval (CI) 1.04, 1.11] for PM(10) (IQR: 3.92 µg/m(3)) and 1.11 [95% CI 1.08, 1.15] for PM(2.5) (IQR: 2.24 µg/m(3)). Living in a neighbourhood with increased levels of deprivation was also associated with gestational hypertension. Any smoking during pregnancy, younger age and higher level of education were inversely associated with risk of gestational hypertension. Compared with non-Hispanic White women, non-Hispanic Black women were at higher risk of gestational hypertension, whereas Hispanic women were at lower risk. Increased levels of PM and neighbourhood deprivation, as well as certain individual characteristics, were associated with higher risk of gestational hypertension.

Associations Between Prenatal Exposure to Air Pollution, Small for Gestational Age, and Term Low Birthweight in a State-Wide Birth Cohort

A range of health effects, including adverse pregnancy outcomes, have been associated with exposure to ambient concentrations of particulate matter (PM) and ozone (O3). The objective of this study was to determine whether maternal exposure to fine particulate matter (PM2.5) and O3 during pregnancy is associated with the risk of term low birthweight and small for gestational age infants in both single and co-pollutant models. Term low birthweight and small for gestational age were determined using all birth certificates from North Carolina from 2003 to 2005. Ambient air concentrations of PM2.5 and O3 were predicted using a hierarchical Bayesian model of air pollution that combined modeled air pollution estimates from the EPA׳s Community Multi-Scale Air Quality (CMAQ) model with air monitor data measured by the EPA׳s Air Quality System. Binomial regression, adjusted for multiple potential confounders, was performed. In adjusted single-pollutant models for the third trimester, O3 concentration was positively associated with small for gestational age and term low birthweight births [risk ratios for an interquartile range increase in O3: 1.16 (95% CI 1.11, 1.22) for small for gestational age and 2.03 (95% CI 1.80, 2.30) for term low birthweight]; however, inverse or null associations were observed for PM2.5 [risk ratios for an interquartile range increase in PM2.5: 0.97 (95% CI 0.95, 0.99) for small for gestational age and 1.01 (95% CI 0.97, 1.06) for term low birthweight]. Findings were similar in co-pollutant models and linear models of birthweight. These results suggest that O3 concentrations in both urban and rural areas may be associated with an increased risk of term low birthweight and small for gestational age births.

Early prenatal exposure to air pollution and its associations with birth defects in a state-wide birth cohort from North Carolina

BACKGROUND Few studies have examined the potential relationship between air pollution and birth defects. The objective of this study was to investigate whether maternal exposure to particulate matter (PM2.5 ) and ozone (O3 ) during pregnancy is associated with birth defects among women living throughout North Carolina. METHODS Information on maternal and infant characteristics was obtained from North Carolina birth certificates and health service data (2003-2005) and linked with information on birth defects from the North Carolina Birth Defects Monitoring Program. The 24-hr PM2.5 and O3 concentrations were estimated using a hierarchical Bayesian model of air pollution generated by combining modeled air pollution predictions from the U.S. Environmental Protection Agencys Community Multi-Scale Air Quality model with air monitor data from the Environmental Protection Agencys Air Quality System. Maternal residence was geocoded and assigned pollutant concentrations averaged over weeks 3 to 8 of gestation. Binomial regression was performed and adjusted for potential confounders. RESULTS No association was observed between either PM2.5 or O3 concentrations and most birth defects. Positive effect estimates were observed between air pollution and microtia/anotia and lower limb deficiency defects, but the 95% confidence intervals were wide and included the null. CONCLUSION Overall, this study suggested a possible relationship between air pollution concentration during early pregnancy and certain birth defects (e.g., microtia/anotia, lower limb deficiency defects), although this study did not have the power to detect such an association. The risk for most birth defects does not appear to be affected by ambient air pollution.

Conceptualizing Neighborhood Space: Consistency and Variation of Associations for Neighborhood Factors and Pregnancy Health Across Multiple Neighborhood Units

The purpose of this research was to assess the consistency of associations between neighborhood characteristics and pregnancy-related behaviors and outcomes across four nested neighborhood boundaries using race-stratified fixed-slope random-intercept multilevel logistic models. High incivilities was associated with increased smoking, inadequate weight gain and pregnancy-induced hypertension (PIH), while walkability was associated with decreased smoking and PIH for white women across all neighborhood definitions. For African American women, high incivilities was associated with increased smoking and inadequate gestational weight gain, while more walkable neighborhoods appeared protective against smoking and inadequate weight gain in all but the smallest neighborhoods. Associations with neighborhood attributes were similar in effect size across geographies, but less precise as neighborhoods became smaller.

An Ecologic Analysis of County-Level PM2.5 Concentrations and Lung Cancer Incidence and Mortality

Few studies have explored the relationship between PM2.5 and lung cancer incidence. Although results are mixed, some studies have demonstrated a positive relationship between PM2.5 and lung cancer mortality. Using an ecologic study design, we examined the county-level associations between PM2.5 concentrations (2002–2005) and lung cancer incidence and mortality in North Carolina (2002–2006). Positive trends were observed between PM2.5 concentrations and lung cancer incidence and mortality; however, the R2 for both were <0.10. The slopes for the relationship between PM2.5 and lung cancer incidence and mortality were 1.26 (95% CI 0.31, 2.21, p-value 0.01) and 0.73 (95% CI 0.09, 1.36, p-value 0.03) per 1 μg/m3 PM2.5, respectively. These associations were slightly strengthened with the inclusion of variables representing socioeconomic status and smoking. Although variability is high, thus reflecting the importance of tobacco smoking and other etiologic agents that influence lung cancer incidence and mortality besides PM2.5, a positive trend is observed between PM2.5 and lung cancer incidence and mortality. This suggests the possibility of an association between PM2.5 concentrations and lung cancer incidence and mortality.

Food insecurity during pregnancy leads to stress, disordered eating, and greater postpartum weight among overweight women.

To investigate the influence of food insecurity on womens stress, disordered eating, dietary fat intake, and weight during the postpartum period.

Evaluating Potential Response-Modifying Factors for Associations between Ozone and Health Outcomes: A Weight-of-Evidence Approach

Background: Epidemiologic and experimental studies have reported a variety of health effects in response to ozone (O3) exposure, and some have indicated that certain populations may be at increased or decreased risk of O3-related health effects. Objectives: We sought to identify potential response-modifying factors to determine whether specific groups of the population or life stages are at increased or decreased risk of O3-related health effects using a weight-of-evidence approach. Methods: Epidemiologic, experimental, and exposure science studies of potential factors that may modify the relationship between O3 and health effects were identified in U.S. Environmental Protection Agency’s 2013 Integrated Science Assessment for Ozone and Related Photochemical Oxidants. Scientific evidence from studies that examined factors that may influence risk were integrated across disciplines to evaluate consistency, coherence, and biological plausibility of effects. The factors identified were then classified using a weight-of-evidence approach to conclude whether a specific factor modified the response of a population or life stage, resulting in an increased or decreased risk of O3-related health effects. Discussion: We found “adequate” evidence that populations with certain genotypes, preexisting asthma, or reduced intake of certain nutrients, as well as different life stages or outdoor workers, are at increased risk of O3-related health effects. In addition, we identified other factors (i.e., sex, socioeconomic status, and obesity) for which there was “suggestive” evidence that they may increase the risk of O3-related health effects. Conclusions: Using a weight-of-evidence approach, we identified a diverse group of factors that should be considered when characterizing the overall risk of health effects associated with exposures to ambient O3. Citation: Vinikoor-Imler LC, Owens EO, Nichols JL, Ross M, Brown JS, Sacks JD. 2014. Evaluating potential response-modifying factors for associations between ozone and health outcomes: a weight-of-evidence approach. Environ Health Perspect 122:1166–1176; http://dx.doi.org/10.1289/ehp.1307541

The Influence of Declining Air Lead Levels on Blood Lead–Air Lead Slope Factors in Children

Background: It is difficult to discern the proportion of blood lead (PbB) attributable to ambient air lead (PbA), given the multitude of lead (Pb) sources and pathways of exposure. The PbB–PbA relationship has previously been evaluated across populations. This relationship was a central consideration in the 2008 review of the Pb national ambient air quality standards. Objectives: The objectives of this study were to evaluate the relationship between PbB and PbA concentrations among children nationwide for recent years and to compare the relationship with those obtained from other studies in the literature. Methods: We merged participant-level data for PbB from the National Health and Nutrition Examination Survey (NHANES) III (1988–1994) and NHANES 9908 (1999–2008) with PbA data from the U.S. Environmental Protection Agency. We applied mixed-effects models, and we computed slope factor, d[PbB]/d[PbA] or the change in PbB per unit change in PbA, from the model results to assess the relationship between PbB and PbA. Results: Comparing the NHANES regression results with those from the literature shows that slope factor increased with decreasing PbA among children 0–11 years of age. Conclusion: These findings suggest that a larger relative public health benefit may be derived among children from decreases in PbA at low PbA exposures. Simultaneous declines in Pb from other sources, changes in PbA sampling uncertainties over time largely related to changes in the size distribution of Pb-bearing particulate matter, and limitations regarding sampling size and exposure error may contribute to the variability in slope factor observed across peer-reviewed studies. Citation: Richmond-Bryant J, Meng Q, Davis A, Cohen J, Lu SE, Svendsgaard D, Brown JS, Tuttle L, Hubbard H, Rice J, Kirrane E, Vinikoor-Imler LC, Kotchmar D, Hines EP, Ross M. 2014. The Influence of declining air lead levels on blood lead–air lead slope factors in children. Environ Health Perspect 122:754–760; http://dx.doi.org/10.1289/ehp.1307072

A multi-level model of blood lead as a function of air lead

National and local declines in lead (Pb) in blood (PbB) over the past several years coincide with the decline in ambient air Pb (PbA) concentrations. The objective of this work is to evaluate how the relationship between PbB levels and PbA levels has changed following the phase out of leaded gasoline and tightened controls on industrial Pb emissions over the past 30 years among a national population sample. Participant-level data from the National Health and Nutrition Examination Survey (NHANES) were employed for two time periods (1988-1994 and 1999-2008), and the model was corrected for housing, demographic, socioeconomic, and other covariates present in NHANES. NHANES data for PbB and covariates were merged with PbA data from the U.S. Environmental Protection Agency. Linear mixed effects models (LMEs) were run to assess the relationship of PbB with PbA; sample weights were omitted, given biases encountered with the use of sample weights in LMEs. The 1988-1994 age-stratified results found that ln(PbB) was statistically significantly associated with ln(PbA) for all age groups. The consistent influence of PbA on PbB across age groups for the years 1988-1994 suggests a ubiquitous exposure unrelated to age of the sample population. The comparison of effect estimates for ln(PbA) shows a statistically significant effect estimate and ANOVA results for ln(PbB) for the 6- to 11-year and 12- to 19-year age groups during 1999-2008. The more recent finding suggests that PbA has less consistent influence on PbB compared with other factors.