Joint effects of ethnic enclave residence and ambient volatile organic compounds exposure on risk of gestational diabetes mellitus among Asian/Pacific Islander women in the United States.

BACKGROUND: Asian/Pacific Islander (API) communities in the United States often reside in metropolitan areas with distinct social and environmental attributes. Residence in an ethnic enclave, a socially distinct area, is associated with lower gestational diabetes mellitus (GDM) risk, yet exposure to high levels of air pollution, including volatile organic compounds (VOCS), is associated with increased GDM risk. We examined the joint effects of ethnic enclaves and VOCs to better understand GDM risk among API women, the group with the highest prevalence of GDM. METHODS: We examined 9069 API births in the Consortium on Safe Labor (19 hospitals, 2002-2008). API ethnic enclaves were defined as areas ≥66th percentile for percent API residents, dissimilarity (geographic dispersal of API and White residents), and isolation (degree that API individuals interact with another API individual). High levels of 14 volatile organic compounds (VOC) were defined as ≥75th percentile. Four joint categories were created for each VOC: Low VOC/Enclave (reference group), Low VOC/No Enclave, High VOC/Enclave, High VOC/No Enclave. GDM was reported in medical records. Hierarchical logistic regression estimated odds ratios (OR) and 95% confidence intervals (95%CI) between joint exposures and GDM, adjusted for maternal factors and area-level poverty. Risk was estimated for 3-months preconception and first trimester exposures. RESULTS: Enclave residence was associated with lower GDM risk regardless of VOC exposure. Preconception benzene exposure was associated with increased risk when women resided outside enclaves [High VOC/No Enclave (OR:3.45, 95%CI:1.77,6.72)], and the effect was somewhat mitigated within enclaves, [High VOC/Enclave (OR:2.07, 95%:1.09,3.94)]. Risks were similar for 12 of 14 VOCs during preconception and 10 of 14 during the first trimester. CONCLUSIONS: API residence in non-enclave areas is associated with higher GDM risk, regardless of VOC level. Ethnic enclave residence may mitigate effects of VOC exposure, perhaps due to lower stress levels. The potential benefit of ethnic enclaves warrants further study.

A nationwide investigation of the impact of the tipped worker subminimum wage on infant size for gestational age.

Tipped workers, primarily women of reproductive-age, can be paid a "subminimum wage" 71% lower than the federal minimum wage. We estimated the effects of increasing the state-level tipped worker subminimum wage (federally, $2.13 per hour) on infant size for gestational age in the US as infants born small or large are at risk for poor health across the lifecourse. Utilizing unconditional quantile regression and difference-in-differences analysis of data from 2004 to 2016 Vital Statistics Natality Files (N = 41,219,953 mother-infant dyads), linked to state-level wage laws, census, and antipoverty policy data, we estimated the effect of increasing the subminimum wage on birthweight standardized for gestational age (BWz). Smallest and largest infants are defined as those in the 5th and 95th BWz percentiles, respectively. Increases in the subminimum wage affected the BWz distribution. When compared to a static wage of $2.13 for the duration of the study period, wage set to 100% of the federal minimum ($5.15-$7.25) was associated with an increase in BWz of 0.024 (95% CI: 0.004, 0.045) for the smallest infants and a decrease by 0.041 (95% CI: -0.054, -0.029) for the largest infants. Increasing the subminimum wage may be one strategy to promote healthier birthweight in infants.

Self-reported depression and social support are associated with egocentric network characteristics of HIV-infected women of color.

BACKGROUND: We explore the social network characteristics associated with depressive symptoms and social support among HIV-infected women of color (WOC). METHODS: Network data were collected from 87 HIV-infected WOC at an academic Infectious Disease clinic in the United States (US) south. With validated instruments, interviewers also asked about depressive symptoms, social support, and treatment-specific social support. Linear regression models resulted in beta coefficients and 95% confidence intervals for the relationships among network characteristics, depression, and support provision. RESULTS: Financial support provision was associated with lower reported depressive symptoms while emotional support provision was associated with increased reported social support. Talking less than daily to the first person named in her network, the primary alter, was associated with a nearly 3-point decrease in reported social support for respondents. Having people in their social network who knew their HIV status was also important. CONCLUSIONS: We found that both functional and structural social network characteristics contributed to perceptions of support by HIV-infected WOC.

Associations of Tipped and Untipped Service Work With Poor Mental Health in a Nationally Representative Cohort of Adolescents Followed Into Adulthood.

Precarious work is concentrated in the service industry in the United States and is a risk factor for poor mental health. Service occupations in which workers receive tips are potentially more precarious due to unstable schedule and income, and lack of benefits. We tested hypotheses that individuals working in tipped service occupations have greater odds of experiencing poor mental health (as indicated by self-reported depression, sleep problems, and/or greater perceived stress) relative to individuals in untipped service and nonservice occupations, using cross-sectional data from wave IV of the National Longitudinal Study of Adolescent to Adult Health data set (2007-2008; age range, 24-33 years). To improve comparability of occupation types, propensity scores were computed as a function of childhood factors, then used to construct a sample of 2,815 women and 2,586 men. In gender-stratified multivariable regression, women in tipped service had greater odds of reporting a depression diagnosis or symptoms relative to women in nonservice work (odds ratio = 1.61; 95% confidence interval: 1.11, 2.34). Associations of similar magnitude for sleep problems and perceived stress were observed among women but were not statistically significant; all associations were close to the null among men. Additional research is necessary to understand the factors that underlie differences in poor mental health in tipped and untipped service versus nonservice workers.

High birth weight modifies association between adolescent physical activity and cardiometabolic health in women and not men.

Recent evidence suggests that adverse prenatal development alters physiological response to physical activity, but longitudinal epidemiologic evidence is scant. This study tested the hypothesis that lower physical activity during adolescence and young adulthood is more strongly associated with later cardiovascular disease (CVD) risk and diabetes or prediabetes (DM/PDM) in women and men who were born with high or low birth weight (HBW, LBW), compared to normal birth weight (NBW). We analyzed data from the National Longitudinal Study of Adolescent to Adult Health, a cohort study of US adolescents followed into adulthood (1994-2009). Using sex-stratified multivariable regression, 30-year CVD risk score (calculated using objective measures; n=12,775) and prevalent DM/PDM (n=15,138) at 24-32years of age were each modeled as a function of birth weight category, self-reported moderate-to-vigorous physical activity frequency in adolescence (MVPA1) and young adulthood (MVPA3), and MVPA-birth weight interactions. Greater MVPA1 was associated with lower 30-year CVD risk score and DM/PDM risk in HBW women but not NBW or LBW women. Associations between MVPA1 and 30-year CVD risk or DM/PDM were not modified by HBW in men; or by LBW in women or men. Additionally, birth weight did not modify estimated effects of MVPA3. Findings suggest that frequent MVPA in adolescence may be a particularly important cardiometabolic risk reduction strategy in girls born HBW; however, we found no evidence that birth weight and MVPA interact in cardiometabolic disease risk in men, for MVPA in adulthood, or for LBW.

Reliability and One-Year Stability of the PIN3 Neighborhood Environmental Audit in Urban and Rural Neighborhoods.

Reliable and stable environmental audit instruments are needed to successfully identify the physical and social attributes that may influence physical activity. This study described the reliability and stability of the PIN3 environmental audit instrument in both urban and rural neighborhoods. Four randomly sampled road segments in and around a one-quarter mile buffer of participants' residences from the Pregnancy, Infection, and Nutrition (PIN3) study were rated twice, approximately 2 weeks apart. One year later, 253 of the year 1 sampled roads were re-audited. The instrument included 43 measures that resulted in 73 item scores for calculation of percent overall agreement, kappa statistics, and log-linear models. For same-day reliability, 81% of items had moderate to outstanding kappa statistics (kappas ≥ 0.4). Two-week reliability was slightly lower, with 77% of items having moderate to outstanding agreement using kappa statistics. One-year stability had 68% of items showing moderate to outstanding agreement using kappa statistics. The reliability of the audit measures was largely consistent when comparing urban to rural locations, with only 8% of items exhibiting significant differences (α < 0.05) by urbanicity. The PIN3 instrument is a reliable and stable audit tool for studies assessing neighborhood attributes in urban and rural environments.

Associations between environmental quality and adult asthma prevalence in medical claims data.

As of 2014, approximately 7.4% of U.S. adults had current asthma. The etiology of asthma is complex, involving genetics, behavior, and environmental factors. To explore the association between cumulative environmental quality and asthma prevalence in U.S. adults, we linked the U.S. Environmental Protection Agency's Environmental Quality Index (EQI) to the MarketScan® Commercial Claims and Encounters Database. The EQI is a summary measure of five environmental domains (air, water, land, built, sociodemographic). We defined asthma as having at least 2 claims during the study period, 2003-2013. We used a Bayesian approach with non-informative priors, implementing mixed-effects regression modeling with a Poisson link function. Fixed effects variables were EQI, sex, race, and age. Random effects were counties. We modeled quintiles of the EQI comparing higher quintiles (worse quality) to lowest quintile (best quality) to estimate prevalence ratios (PR) and credible intervals (CIs). We estimated associations using the cumulative EQI and domain-specific EQIs; we assessed U.S. overall (non-stratified) as well as stratified by rural-urban continuum codes (RUCC) to assess rural/urban heterogeneity. Among the 71,577,118 U.S. adults with medical claims who could be geocoded to county of residence, 1,147,564 (1.6%) met the asthma definition. Worse environmental quality was associated with increased asthma prevalence using the non-RUCC-stratified cumulative EQI, comparing the worst to best EQI quintile (PR:1.27; 95% CI: 1.21, 1.34). Patterns varied among different EQI domains, as well as by rural/urban status. Poor environmental quality may increase asthma prevalence, but domain-specific drivers may operate differently depending on rural/urban status.

County-level cumulative environmental quality associated with cancer incidence.

BACKGROUND: Individual environmental exposures are associated with cancer development; however, environmental exposures occur simultaneously. The Environmental Quality Index (EQI) is a county-level measure of cumulative environmental exposures that occur in 5 domains. METHODS: The EQI was linked to county-level annual age-adjusted cancer incidence rates from the Surveillance, Epidemiology, and End Results (SEER) Program state cancer profiles. All-site cancer and the top 3 site-specific cancers for male and female subjects were considered. Incident rate differences (IRDs; annual rate difference per 100,000 persons) and 95% confidence intervals (CIs) were estimated using fixed-slope, random intercept multilevel linear regression models. Associations were assessed with domain-specific indices and analyses were stratified by rural/urban status. RESULTS: Comparing the highest quintile/poorest environmental quality with the lowest quintile/best environmental quality for overall EQI, all-site county-level cancer incidence rate was positively associated with poor environmental quality overall (IRD, 38.55; 95% CI, 29.57-47.53) and for male (IRD, 32.60; 95% CI, 16.28-48.91) and female (IRD, 30.34; 95% CI, 20.47-40.21) subjects, indicating a potential increase in cancer incidence with decreasing environmental quality. Rural/urban stratified models demonstrated positive associations comparing the highest with the lowest quintiles for all strata, except the thinly populated/rural stratum and in the metropolitan/urbanized stratum. Prostate and breast cancer demonstrated the strongest positive associations with poor environmental quality. CONCLUSION: We observed strong positive associations between the EQI and all-site cancer incidence rates, and associations differed by rural/urban status and environmental domain. Research focusing on single environmental exposures in cancer development may not address the broader environmental context in which cancers develop, and future research should address cumulative environmental exposures. Cancer 2017;123:2901-8. © 2017 American Cancer Society.

Comparison of gestational dating methods and implications for exposure-outcome associations: an example with PM2.5 and preterm birth.

OBJECTIVES: Estimating gestational age is usually based on date of last menstrual period (LMP) or clinical estimation (CE); both approaches introduce potential bias. Differences in methods of estimation may lead to misclassification and inconsistencies in risk estimates, particularly if exposure assignment is also gestation-dependent. This paper examines a 'what-if' scenario in which alternative methods are used and attempts to elucidate how method choice affects observed results. METHODS: We constructed two 20-week gestational age cohorts of pregnancies between 2000 and 2005 (New Jersey, Pennsylvania, Ohio, USA) using live birth certificates: one defined preterm birth (PTB) status using CE and one using LMP. Within these, we estimated risk for 4 categories of preterm birth (PTBs per 106 pregnancies) and risk differences (RD (95% CIs)) associated with exposure to particulate matter (PM2.5). RESULTS: More births were classified preterm using LMP (16%) compared with CE (8%). RD divergences increased between cohorts as exposure period approached delivery. Among births between 28 and 31 weeks, week 7 PM2.5 exposure conveyed RDs of 44 (21 to 67) for CE and 50 (18 to 82) for LMP populations, while week 24 exposure conveyed RDs of 33 (11 to 56) and -20 (-50 to 10), respectively. CONCLUSIONS: Different results from analyses restricted to births with both CE and LMP are most likely due to differences in dating methods rather than selection issues. Results are sensitive to choice of gestational age estimation, though degree of sensitivity can vary by exposure timing. When both outcome and exposure depend on estimate of gestational age, awareness of nuances in the method used for estimation is critical.

Serum Antioxidants Are Associated with Serum Reproductive Hormones and Ovulation among Healthy Women.

BACKGROUND: Evidence is growing that the equilibrium between reactive oxygen species and antioxidants plays a vital role in women's reproductive health. OBJECTIVE: The objective of this study was to evaluate variations in serum antioxidant concentrations across the menstrual cycle and associations between antioxidants and reproductive hormones and anovulation among healthy women. METHODS: The BioCycle Study, a prospective cohort, followed 259 women aged 18-44 y for up to 2 menstrual cycles. Serum fat-soluble vitamin and micronutrient (α-tocopherol, γ-tocopherol, retinol, lutein, lycopene, and ß-carotene), ascorbic acid, and reproductive hormone concentrations were measured 5-8 times/cycle. We used weighted linear mixed models to assess associations between antioxidants and hormone concentrations, after adjustment for age, race, body mass index, parity, sleep, pain medication use, total energy intake, concurrent hormones, serum cholesterol, F2-isoprostanes, and other antioxidants. Generalized linear models were used to identify associations with anovulation. RESULTS: Serum antioxidant concentrations varied across the menstrual cycle. Retinol and α-tocopherol were associated with higher estradiol [RR: 1.00 pg/mL (95% CI: 0.67, 1.34 pg/mL); RR: 0.02 pg/mL (95% CI: 0.003, 0.03 pg/mL), respectively] and testosterone [RR: 0.61 ng/dL (95% CI: 0.44, 0.78 ng/dL); RR: 0.01 ng/dL (95% CI: 0.001, 0.01 ng/dL), respectively]. Ascorbic acid was associated with higher progesterone (RR: 0.15 ng/mL; 95% CI: 0.05, 0.25 ng/mL) and with lower follicle-stimulating hormone (RR: -0.06 mIU/mL; 95% CI: -0.09, -0.03 mIU/mL). The ratio of α- to γ-tocopherol was associated with an increased risk of anovulation (RR: 1.03; 95% CI: 1.01, 1.06). CONCLUSIONS: These findings shed new light on the intricate associations between serum antioxidants and endogenous hormones in healthy premenopausal women and support the hypothesis that concentrations of serum vitamins affect steroidogenesis even after adjustment for oxidative stress.

Potentially traumatic experiences and sexual health among orphaned and separated adolescents in five low- and middle-income countries.

Orphans and separated children (OSC) are a vulnerable population whose numbers are increasing, particularly in sub-Saharan Africa and Asia. Over 153 million children worldwide have lost one or both parents, including 17 million orphaned by AIDS, and millions more have been separated from their parents. As younger orphans enter adolescence, their sexual health and HIV-related risk behaviors become key considerations for their overall health. Importantly, their high prevalence of exposure to potentially traumatic events (PTEs) may put OSC at additional risk for adverse sexual health outcomes. The Positive Outcomes for Orphans study followed OSC randomly sampled from institution-based care and from family-based care, as well as a convenience sample of non-OSC, at six sites in five low-and middle-income countries. This analysis focused on the 90-month follow-up, during which adolescents 16 and older were assessed for sexual health, including age at sexual debut, past-year sex, past-year condom use, and perceptions of condom use. We specifically examined the relationship between PTEs and sexual health outcomes. Of the 1258 OSC and 138 non-OSC assessed, 11% reported ever having sex. Approximately 6% of participants reported recent sex and 5% reported having recent unprotected sex. However, 70% of those who had recent sex reported that they did not use a condom every time, and perceptions of condom use tended to be unfavorable for protection against sexual risk behavior. Nearly all (90%) of participants reported experiencing at least one lifetime PTE. For those who experienced "any" PTE, we found increased prevalence of recent sex (PR = 1.39 [0.47, 4.07]) and of recent unprotected sex (PR = 3.47 [0.60, 19.91]). This study highlights the need for caregivers, program managers, and policymakers to promote condom use for sexually active OSC and identify interventions for trauma support services. Orphans living in family-based care may also be particularly vulnerable to early sexual debut and unprotected sexual activity.

Civic engagement among orphans and non-orphans in five low- and middle-income countries.

BACKGROUND: Communities and nations seeking to foster social responsibility in their youth are interested in understanding factors that predict and promote youth involvement in public activities. Orphans and separated children (OSC) are a vulnerable population whose numbers are increasing, particularly in resource-poor settings. Understanding whether and how OSC are engaged in civic activities is important for community and world leaders who need to provide care for OSC and ensure their involvement in sustainable development. METHODS: The Positive Outcomes for Orphans study (POFO) is a multi-country, longitudinal cohort study of OSC randomly sampled from institution-based care and from family-based care, and of non-OSC sampled from the same study regions. Participants represent six sites in five low-and middle-income countries. We examined civic engagement activities and government trust among subjects > =16 years old at 90-month follow-up (approximately 7.5 years after baseline). We calculated prevalences and estimated the association between key demographic variables and prevalence of regular volunteer work using multivariable Poisson regression, with sampling weights to accounting for the complex sampling design. RESULTS: Among the 1,281 POFO participants > =16 who were assessed at 90-month follow-up, 45 % participated in regular community service or volunteer work; two-thirds of those volunteers did so on a strictly voluntary basis. While government trust was fairly high, at approximately 70 % for each level of government, participation in voting was only 15 % among those who were > =18 years old. We did not observe significant associations between demographic characteristics and regular volunteer work, with the exception of large variation by study site. CONCLUSION: As the world's leaders grapple with the many competing demands of global health, economic security, and governmental stability, the participation of today's youth in community and governance is essential for sustainability. This study provides a first step in understanding the degree to which OSC from different care settings across multiple low- and middle-income countries are engaged in their communities.

From fatalism to mitigation: A conceptual framework for mitigating fetal programming of chronic disease by maternal obesity.

Prenatal development is recognized as a critical period in the etiology of obesity and cardiometabolic disease. Potential strategies to reduce maternal obesity-induced risk later in life have been largely overlooked. In this paper, we first propose a conceptual framework for the role of public health and preventive medicine in mitigating the effects of fetal programming. Second, we review a small but growing body of research (through August 2015) that examines interactive effects of maternal obesity and two public health foci - diet and physical activity - in the offspring. Results of the review support the hypothesis that diet and physical activity after early life can attenuate disease susceptibility induced by maternal obesity, but human evidence is scant. Based on the review, we identify major gaps relevant for prevention research, such as characterizing the type and dose response of dietary and physical activity exposures that modify the adverse effects of maternal obesity in the offspring. Third, we discuss potential implications of interactions between maternal obesity and postnatal dietary and physical activity exposures for interventions to mitigate maternal obesity-induced risk among children. Our conceptual framework, evidence review, and future research directions offer a platform to develop, test, and implement fetal programming mitigation strategies for the current and future generations of children.

The associations between environmental quality and preterm birth in the United States, 2000-2005: a cross-sectional analysis.

BACKGROUND: Many environmental factors have been independently associated with preterm birth (PTB). However, exposure is not isolated to a single environmental factor, but rather to many positive and negative factors that co-occur. The environmental quality index (EQI), a measure of cumulative environmental exposure across all US counties from 2000-2005, was used to investigate associations between ambient environment and PTB. METHODS: With 2000-2005 birth data from the National Center for Health Statistics for the United States (n = 24,483,348), we estimated the association between increasing quintiles of the EQI and county-level and individual-level PTB; we also considered environmental domain-specific (air, water, land, sociodemographic and built environment) and urban-rural stratifications. RESULTS: Effect estimates for the relationship between environmental quality and PTB varied by domain and by urban-rural strata but were consistent across county- and individual-level analyses. The county-level prevalence difference (PD (95% confidence interval) for the non-stratified EQI comparing the highest quintile (poorest environmental quality) to the lowest quintile (best environmental quality) was -0.0166 (-0.0198, -0.0134). The air and sociodemographic domains had the strongest associations with PTB; PDs were 0.0196 (0.0162, 0.0229) and -0.0262 (-0.0300, -0.0224) for the air and sociodemographic domain indices, respectively. Within the most urban strata, the PD for the sociodemographic domain index was 0.0256 (0.0205, 0.0307). Odds ratios (OR) for the individual-level analysis were congruent with PDs. CONCLUSION: We observed both strong positive and negative associations between measures of broad environmental quality and preterm birth. Associations differed by rural-urban stratum and by the five environmental domains. Our study demonstrates the use of a large scale composite environment exposure metric with preterm birth, an important indicator of population health and shows potential for future research.

Racial residential segregation and preterm birth: built environment as a mediator.

BACKGROUND: Racial residential segregation has been associated with preterm birth. Few studies have examined mediating pathways, in part because, with binary outcomes, indirect effects estimated from multiplicative models generally lack causal interpretation. We develop a method to estimate additive-scale natural direct and indirect effects from logistic regression. We then evaluate whether segregation operates through poor-quality built environment to affect preterm birth. METHODS: To estimate natural direct and indirect effects, we derive risk differences from logistic regression coefficients. Birth records (2000-2008) for Durham, North Carolina, were linked to neighborhood-level measures of racial isolation and a composite construct of poor-quality built environment. We decomposed the total effect of racial isolation on preterm birth into direct and indirect effects. RESULTS: The adjusted total effect of an interquartile increase in racial isolation on preterm birth was an extra 27 preterm events per 1000 births (risk difference = 0.027 [95% confidence interval = 0.007 to 0.047]). With poor-quality built environment held at the level it would take under isolation at the 25th percentile, the direct effect of an interquartile increase in isolation was 0.022 (-0.001 to 0.042). Poor-quality built environment accounted for 35% (11% to 65%) of the total effect. CONCLUSION: Our methodology facilitates the estimation of additive-scale natural effects with binary outcomes. In this study, the total effect of racial segregation on preterm birth was partially mediated by poor-quality built environment.

Impact of a routine, opt-out HIV testing program on HIV testing and case detection in North Carolina sexually transmitted disease clinics.

BACKGROUND: The impact of routine, opt-out HIV testing programs in clinical settings is inconclusive. The objective of this study was to estimate the impact of an expanded, routine HIV testing program in North Carolina sexually transmitted disease (STD) clinics on HIV testing and case detection. METHODS: Adults aged 18 to 64 years who received an HIV test in a North Carolina STD clinic from July 1, 2005, through June 30, 2011, were included in this analysis, dichotomized at the date of implementation on November 1, 2007. HIV testing and case detection counts and rates were analyzed using interrupted time series analysis and Poisson and multilevel logistic regression. RESULTS: Preintervention, 426 new HIV-infected cases were identified from 128,029 tests (0.33%), whereas 816 new HIV-infected cases were found from 274,745 tests postintervention (0.30%). Preintervention, HIV testing increased by 55 tests per month (95% confidence interval [CI], 41-72), but only 34 tests per month (95% CI, 26-42) postintervention. Increases in HIV testing rates were most pronounced in women and non-Hispanic whites. A slight preintervention decline in case detection was mitigated by the intervention (mean difference, 0.01; 95% CI, -0.02 to 0.05). Increases in case detection rates were observed among women and non-Hispanic blacks. CONCLUSIONS: The impact of a routine HIV screening in North Carolina STD clinics was marginal, with the greatest benefit among persons not traditionally targeted for HIV testing. The use of a preintervention comparison period identified important temporal trends that otherwise would have been ignored.

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.

Construction of an environmental quality index for public health research.

BACKGROUND: A more comprehensive estimate of environmental quality would improve our understanding of the relationship between environmental conditions and human health. An environmental quality index (EQI) for all counties in the U.S. was developed. METHODS: The EQI was developed in four parts: domain identification; data source acquisition; variable construction; and data reduction. Five environmental domains (air, water, land, built and sociodemographic) were recognized. Within each domain, data sources were identified; each was temporally (years 2000-2005) and geographically (county) restricted. Variables were constructed for each domain and assessed for missingness, collinearity, and normality. Domain-specific data reduction was accomplished using principal components analysis (PCA), resulting in domain-specific indices. Domain-specific indices were then combined into an overall EQI using PCA. In each PCA procedure, the first principal component was retained. Both domain-specific indices and overall EQI were stratified by four rural-urban continuum codes (RUCC). Higher values for each index were set to correspond to areas with poorer environmental quality. RESULTS: Concentrations of included variables differed across rural-urban strata, as did within-domain variable loadings, and domain index loadings for the EQI. In general, higher values of the air and sociodemographic indices were found in the more metropolitan areas and the most thinly populated areas have the lowest values of each of the domain indices. The less-urbanized counties (RUCC 3) demonstrated the greatest heterogeneity and range of EQI scores (-4.76, 3.57) while the thinly populated strata (RUCC 4) contained counties with the most positive scores (EQI score ranges from -5.86, 2.52). CONCLUSION: The EQI holds promise for improving our characterization of the overall environment for public health. The EQI describes the non-residential ambient county-level conditions to which residents are exposed and domain-specific EQI loadings indicate which of the environmental domains account for the largest portion of the variability in the EQI environment. The EQI was constructed for all counties in the United States, incorporating a variety of data to provide a broad picture of environmental conditions. We undertook a reproducible approach that primarily utilized publically-available data sources.

Examining modification of the associations between air pollution and birth outcomes by neighborhood deprivation in a North Carolina birth cohort, 2011-2015.

Background: Evidence from studies of air pollutants and birth outcomes suggests an association, but uncertainties around geographical variability and modifying factors still remain. As neighborhood-level social characteristics are associated with birth outcomes, we assess whether neighborhood deprivation level is an effect measure modifier on the association between air pollution and birth outcomes in a North Carolina birth cohort. Methods: Using birth certificate data, all North Carolina residential singleton live births from 1 January 2011 to 31 December 2015 with gestational ages of 20-44 weeks (n = 566,799) were examined for birth defect diagnoses and preterm birth. Exposures were daily average fine particulate matter (PM2.5), daily 8-h maximum nitrogen dioxide (NO2), and daily 8-h maximum ozone (O3) modeled concentrations, and the modifier of interest was the neighborhood deprivation index (NDI). Linear binomial models were used to estimate the prevalence differences and 95% confidence intervals (CI) for the association between ambient air pollution and birth defect diagnoses. Modified Poisson regression models were used to estimate risk differences (RDs) and 95% CIs for air pollution and preterm birth. Models were stratified by the neighborhood deprivation index group (low, medium, or high) to assess potential modification by NDI. Results: Approximately 3.1% of the study population had at least one birth defect and 8.18% were born preterm. For preterm birth, associations with PM2.5 and O3 did not follow a conclusive pattern and there was no evidence of modification by NDI. The associations between NO2 and preterm birth were generally negative across exposure windows except for a positive association with NO2 and preterm birth for high NDI [RD: 34.70 (95% CI 4.84-64.56)] for entire pregnancy exposure. There was no evidence of associations between pollutants examined and birth defects. Conclusions: There may be differences in the association between NO2 exposure and preterm birth by NDI but we did not observe any evidence of associations for birth defects. Our results support the public health protection afforded by reductions in air pollution, even in areas of neighborhood deprivation, but future research conducted in areas with higher levels of air pollution and evaluating the potential for modification by neighborhood deprivation level would be informative.